Hilarious. I thought id get some good ideas on how to fix some problems and finish projects my dad started but never got to finish himself and eight minutes in im thinking well damn, guess i will have to start at the ground and just replace all the entire foundation....and redo the walls and siding....and...hmmm maybe just move away
This video should be required reading/viewing for anyone buying a home with a basement or building a new home with a basement. The very best in depth analysis I have seen.
@@CMCraftsman Just finished watching this video and wonder if it was still relevant anymore. Where are you getting the latest and greatest information?
This certainly is one of the better YT videos I watched and learned so much information about proper foundation/slab assembly and "why" one should construct this way. Also having a real-life mock-up with labels, pointing and demonstrating helps a ton!! Very well done sir!
Excellent information! I am just beginning to plan my future home build here in Ohio and after reading 100s of articles and watching 100s of videos on building science strategies, I've learned that the most important thing to get right, by far, are the 4 envelope control layers (water, vapor, air, thermal). If you spend an appropriate amount of the budget on getting the envelope right, you will absolutely prevent problems down the road AND get a more comfortable house, overall. I've decided to go all out with my envelope and try to save some money on aesthetics, which can always be upgraded later. It's the structural details that should never be overlooked during initial construction because they're not easy to fix later.
Wow Pat, this is the best video explanation I've found, and I'm 65, so I've seen many. Thank you Sir for sharing this knowledge of yours so simply & understanding to us. The enigma is over... Cheers :)
This is the most thorough-going, understandable presentation on foundation moisture management that I've ever seen. The information here could save you tens of thousands of dollars.
I'm owner-building my first home in Anchorage, Alaska. This is by far the most helpful video I've found on how to build an effective cold-climate foundation. Thanks a ton for the work in putting this together.
Hi Paxson! How did the build go and did you insulate from the outside!?? I'm wanting to build in northern Ontario and looking to build foundation and walls of bungalow with block. No lumber but the floor and roof Your feedback and experience would be a huge plus. Thanks! Mike
@@mattmag3089 the project was disastrous, unfortunately. The GC I hired to frame the house did such a bad job we ended up having to tear the house down. The project is in limbo and I'm renting now.
I learned a lot from this expert. I have been a Framer in Calgary Canada for over 10 years. I am going to take a 3 year course next Fall called Energy Systems Engineering Technologies. Thank you Mr. Expert, Great video.
@@ryanshannon6963 TV Ontario did a whole series called "R-2000 The Better Built House". If you can find it its well worth watching. This series covered the proper installation of air and vapour barriers that hardly any builders or renovators follow or understand.
What I found was that builders would take the course and then get R-2000 certified on one house, and then go back to their old practices claiming their houses were R-2000 compliant. I was trimming one of these houses and the air was blowing right in under the bottom plate of the wall assembly proving they had not sealed the envelope of the house properly.
Very informative and you saved me a pile of money, I was thinking of finishing the basement but after seeing how it's nearly impossible to do without problems I said forget it.
This is one of the best videos for the fundamentals of understanding what the heck is going on with insulation in a building I’ve seen. Solid recommend, 10/10 almost certainly will watch this again. Thank you for making this content available!
One thing to keep in mind is that if you insulate a concrete basement or even slab on grade from the outside. You are giving the house a huge thermal mass. An other way say thermal mass is a thermal reservoir because it is a mass that stores hot or cold. This thermal reservoir will make a huge difference in emergence situation where the house looses heating. The warm "indoor" concrete in the basement will keep the home warm probably for several days if not a week even with extreme conditions outside if the house is properly insulated.
I agree... did project where the engineer had no insulation under the basement floor slab (just a really good moisture barrier) he claimed that the earth under the slab becomes part of that thermal mass as you explained...
Great video to educate people in the construction business as well as homeowners. It's often hard to sell clients on proper building methods to prevent potential issues like mold to develop in sealed tight homes. ICF seems to be a good alternative method to constructing a basement.
Ive watched tons of videos on insulating and framing basement walls. This is the first that makes it truly understandable and its a very in depth video. Thanks!
This is a fantastic video. As a first time home buyer trying to understand the fundamentals of building science so I can better choose a home, this is invaluable. Thank you for taking the time to put this together!
Great video, thank you for the education. I have learned so much more here in 30 minutes than all my discussions with contractors and building suppliers! Best regards.
Sir. I can't thank you enough. Just perfect you and your colleagues well done! Answers to questions I didn't quite have yet. Everyone needs to see this first!
Thank you for this video. My house was built about 17 years ago; I have owned it just 2 years. I was going to finish the basement but ran out of money since I totally renovated the upper floors. Instead I applied DryLok Extreme - 2 coats covered by SW reflective white paint. The walls were reinforced poured concrete with a brick pattern on both sides. If anybody is thinking of this - use Thro Seal and save your shoulder. Both are "pulled into the concrete" and virtually impossible to roll due to the brick pattern. The floors were painted with two coats of SW concrete paint. NO dampness, not cold? I dug around the foundation and found the builder had tarred the foundation, covered it with a mesh, a second coat of tar and then applied 4" of rigid foam insulation. A Swiffer is all you need to maintain the basement. After this video I understand why the contractor put that insulation on the OUTSIDE. I don't have to think twice about off-gassing.
I intuitively knew that placing the insulation outside was a much better option but when my parents had their house built they did what the builder recommended and placed it on the inside house. And I inherited the house. This video post just reminded about the costly mistakes made building it, As side note I would use Aerated Concrete (it just has so many advantages and only a few disadvantages) and use a robust vapor/moisture barrier system if I would ever have a house built at this point, But since megatition is the only option for this house. My choice will probably be the less costly and less effective interior megatition option since digging around the whole house seem like it will be to costly for moderate moisture issue that I have experienced. Good luck finishing ur project too. So it goes to prove the old expression is correct "an ounce of prevention is worth a pound of cure"
Wish I would have found this 3 years ago BEFORE I built a new cabin in Northern Wisconsin. This video is at least 10 years old, why isn't this more common info by now and hasn't been adopted / required by the building practices. I insulated inside with 1" foil faced placed tight to the foundation wall, foil side facing in. Taped all seams. Then built my 2x4 framed wall and added 2" foam sheets to the wall cavity. Hindsight, I would have placed both 1" and 2" behind the wall framing to make running electric easier. I would have only lost a total of 4" in overall length and width of the basement, been able to attach full sheets of insulation. Great information... maybe next build... if I ever do.
This is the best information on moisture and insulation in a basement I have ever seen! He address the complicated relationship between moisture movement and heat movement. Thank you, thank you, thank you
Fantastic, well thought out video. Thank you. Q: We've just poured our basement walls. Footer rests on natural undisturbed ground (mostly though there are slight gaps here n there under the footer form, they were filled with concrete that spread out a bit. Footer was a very tight, stony mix) The walls were a looser mix and our contractor has never used a capillary barrier and even after asking for it, it was "forgotten" and so the walls are up and in forms over the long weekend. Our footer drain is in its own ditch alongside the footer and about 1/2 of it's diameter below the footer bottom and out from the footer about 4", completely filled with clean stone to the top of the footer. The plan is for 2" xps and a dimple board outside of that with native fill against that. A plastic barrier up the wall a foot above the footer, behind foam board, down and across the top of footer and onto the clean stone above the drain. There will be a ditch drain at the surface with clean stone and a 4" perf pipe, tied by vertical "downspouts" into the footer drain. Because of siding overhang issues with builder we've agreed to not take the insulation up over the rim joist. Rather, the foam and dimple board will end at top of fndn wall and we will spray-foam that rim-joist void from the inside. My understanding is the spray foam will not allow for vapor trapping and so will not be a major source of heat or vapor transfer. And, no mold. So the only place we're not good here (I think) is that vapor up through the footer. Since this is how homes have been built for so long, my questions are (science aside, I'm sold that it should have been done) just how big of an issue could this be? What can be done now to mitigate it and, would it be cost effective?
This could be a very BIG issue depending on you ground/soil conditions. If you have issues or are concerned that you may have issues with water/vapor up through the floor/footer I would recommend a second drain tile on the interior side of the footing draining to a sump pump.
The overall point is to make sure your basement wall and floor have been properly waterproofed/damp proofed from the outside. After this is done insulate from inside, especially top portion of concrete wall where it is exposed to cold air. (North climate). A dehumidifier is a good to have too.
Pat Huelman : very informative to the non skilled builders out there. An additional approach based on that you don't build where a natural swimming hole exists is if possible build higher out of the ground and back slope to move water away naturally from the foundation while still implimenting all the details that you have shown. In addition if the backslope is not too extreme a piece of poly plastic can be placed 4 to 6 inches under the soil slope to move surface water dramatically away from the building and possibly the outer edge of the plastic drainage slope intersecting a french drain there by keeping a large dry mass of soil surrounding the building.
Basements are fantastic though - for all kinds of reasons including a nuclear bunker! lol! I want a basement but man its stupid expensive to build properly and for the long haul.
I get it but the thing is if you need frost protection a basement is ideal and the cheapest way to expand livable building space. I’ve had a few houses with basements and they’ve done well.
Am glad to see someone finally talking so much about Moisture. I basically deal with retrofit so there is usually no water proofing in the homes I come across. The only solution I could add for folks is to spray on Penetrating Concrete Sealer onto inside concrete block foundation walls and cement slabs. This doesn't quite get the footing sealed, spraying from the inside so I often dig up outside perimeter and spray the footing then exterior foam. Just wanted to offer penetrating sealer option
The external insulation combined with the making it look pretty on the outside, is making a perfect channel for termites to get into your house without you ever knowing it.
Wow! Mr. Huelman, what a wonderful presentation on the nuances of foundation design and management. It was very informative. Thank you for your knowledge and clarity.
This feels like the presentation for ICF foundation systems. Checking most if not all of the boxes when paired with a perc outer wall treatment & slab assembly.
Excellent! Just wish you showed exterior insulation using other products like mineral wool, or graphite polystyrene. Keep in mind that foam products make great nesting material for insects, even below grade. I've seen insects in foam in northern Michigan, it is not just a hot/warm climate issue. Thanks for the excellent videos on the subject of below-grade insulation.
Great video. Pat touched on so many issues but was superficial on some critical parts of the waterproofing system. From over 20 years of experience I can add that the most important part of the waterproofing system is the exterior drain tile. 99% of all drain tile installation on new construction are done pretty quickly with almost no effort to paying attention to making sure the tile is completely clean of any foreign matter. You can waterproof using the Ferrari of systems but if you have a clogged or obstructed tile system water can and will go through; it's not a boat. Also I think the worst method of waterproofing a basement from the interior is to use spray foam (closed or open cell). The reason for that is that moisture is standing on the outer side of the foam waiting to infiltrate and has no way of trickling in any direction because it's essentially glued to the concrete. Concrete can and will crack in turn cracking the insulation with it since it's glued to it. Now you have a huge problem because you have a channel of water infiltrating all the water from all sides. I've seen it it's not theory it's experience. NEVER use foam. Basically the best system is the driest system. Follow gravity and concentrate on the bottom part. Drain tile, sump system, a good pump kit will give you a comfortable basement even with minimal bells and whistles. Again it's a great video thank you for posting it.
your thinking is compartmentalized...your experience simply sheds light on improper installation and techniques from construction jokers...no disrespect
mark drysdale I'm sure you'd be the historical reference on the marvels of Aristotele, Leonardo da Vinci, Michelangelo and the likes. We're eternally grateful for your precious thinking and input.
There is some good "stuff" which looks like a dimpled fabric that is put over the tarred foundation and goes down to the drain tile. The drain tile is covered with a silt cloth and in my prior house has a clean-out at ground level so I can get a hose in there to wash out the silt - which I never had to do. My downspouts all fed into a 6" schedule 40 rigid pipe that ran to light about 40" from the house. This house has some of the same features but the external drain runs to the storm sewer. I also have 3 sump pumps: 1) a grinder pump so I can add a toilet down there if I want; 2) a regular sump pump and 3) a water powered back-up sump pump. I sealed all the sump pumps because there is radon in the soil around here and while I don't have a problem I just wanted the protection. If you have enough space, burying the "horizontal" pipe that collects the gutter water is the best solution. My basement is not damp, cold or musty.
I have a 100 year old house with quadruple wythe brick walls in the former coal cellar Basement but a poured foundation and no drain tiles. I couldn't get to the exterior wall without digging up my neighbors entire yard. I parged the imside walls of the one leaky side (wasnt that leaky) of the Basement, glued up foil faced polyiso on all 4 walls from floor to rim joist using like 50 tubes of PL Foam adhesive, which has no initial grab, but is great after a week (literally a week). Then furred that out with PT 1×4 16"OC vertical, then Horizontal. Drywalled with greenboard and tiled the floor. I'm slow as molasses and had a kid in the middle. Took me 2 years to finish (did a bunch of electrical and plumbing upgrades in middle plus jackhammered floor and poured piers with which I jacked up kitchen on lally columns), ANYWAY 5 years afterward - Amazingly - no water. No moisture problems. Split it into two rooms: office and laundry room. Polished a HUGE TURD and has worked out well for us. People thought I was crazy.
When one thinks about it, when you're in the frozen North, you don't eat your winter parka. The parka works best on the OUTSIDE. And I think I read where Mt Everest climbers learned to put vapor barriers on the INSIDE of their sleeping bags to prevent their moisture from freezing halfway out. Always place the vapor barrier on the side with the greatest vapor pressure. This video is great at explaining the best way to insulate a home in the Northern states. Best done on new construction though...
Hello Pat and thank you for one of the most informative videos on this subject. Question: Though I have no water issues in my below-grade block walls, I still applied UGL's Drylock Waterproofer to the walls as an added measure. Next, I built a stud wall, keeping the studs about 1/2" from the block wall, and insulated with unfaced fiberglass insulation. Then I applied Certainteed's "Membrain" to the inside of the stud wall. The Membrain repels vapor from the inside of the basement (keeping vapor from getting into the insulation) and allows vapor in the insulation (if any) to permeate inward to the inside of the basement. 1/2" Water/Mold Resistant drywall was used as the inside finished wall. Aside from your concerns about a water event that could soak the drywall or fiberglass insulation (though possible, is not likely in my case as I have pretty good drainage in the basement), do you feel that what I've done is adequate? I should also add the I have added two intake vents to the basement that draw air to the heating and cooling system. There were no intake vents there before and the basement only had a very small area of mold growth behind a large cabinet placed next to the wall. Thanks, Steve
I have lived in a all brick 1908 home for 38 years. After spending a lot of studying this issue and radon gas. I chose to let it brick breathe some air leaks up a wall into the attic. The benefit for me is a much lower radon gas, dehumidifier and a higher heating and cooling cost. But I know the home is much better air quality.
This master professor is my hero and ofcourse the video creator. I wish I can find other masters with relative ease in other not so related industries and learn scientific theories, evidence and so forth. Thank you to both of you for putting out this article.
Yes a house completely foam board insulated and made air and water tight everywhere on the outside is the ideal home. All new construction should use this technique.
This is probably the most important videos on this topic Everyone should have to watch this first before watching all those crazy ideas out there. The one slip I heard was when he used the word Polyiso,(26:32) which I would not recommend on a wall as it can become a vapor trap for moisture.
2 years of listening to so many video's without answering the problem i am experiencing. At 6 minutes, approx 20 seconds, you are the 1st to give me the answer. Plus, at 28:24. Right now the corner of my house has been dug by tractor shovel to the drain. I removed the 1 inch fiber insulation that was soak & wet, why do they use this stuff? Gets wet and freezes. We get minus 45 Celsius/Fahrenheit temps. That made the inside wall sweat so much behind the pink insulation, that i had a ice buildup of up to 1/2 inch inside. Though i had water coming in from roof... thank you for this amazing video. I will share it at large. Cheers. PS: any other suggestions, feel free to let me know please. Going in to do the work in couple/few days after rain stops. The water table is very high here.
Great video. I'd like to suggest that a basement wall with insulating batts should employ rock wool instead of fiberglass. Rock wool is hydrophobic. It will not absorb or hold water even if exposed to liquid water. So, in the event of a flood or plumbing disaster, it would not have to be dried out. Perhaps the wood wall construction would need a little drying. Your drywall will be cashed and need to be removed anyway. Rock wool will also inhibit mold growth due to its inability to hold water. What opinions do you have about products that supposedly "seal" concrete such as RadonSeal?
Not just watch it, Pay attention. Who knows how they finished up the job, late Friday afternoon, just wanting to get to the bar! No one knows whats behind that dirt once backfilled.
Thank you for that video. I'm assuming that on existing homes where the outside has not been insulated, that you are left with no other choice than to insulate, and vapor barrier the inside foundation wall ? ...or would you still leave it alone and take the heat loss in exchange for risk aversion to moisture buildup ?
One of the best explanations on foundation insulation and moisture mitigation I have seen. I now better understand how and why my 32 year old concrete block foundation does what it does. I have efflorescence on the walls, mostly at the bottom course and the top few, exposed to outside air. The foundation was waterproofed with a product called Theroseal. It adhered and held up quite well on the outside foundation walls but unfortunately does not have good waterproofing properties. It probably would have been better to just use an asphalt coating. If I were to build a home today I would certainly use the techniques described in this video. Now if I could just find a way to stop the efflorescence on the inside walls. The last product I tried on some of the virgin walls was a product called Hydro-seal 75, an epoxy paint product. Now after about a year the efflorescence is pushing the paint off the walls. It works great on the areas where there was no efflorescence.
Great video, thanks for sharing:) I'm curious as to what you would recommend as the best insulation and install if you had no choice but to insulate a basement from the inside?
Our house was moved to it's present location in 1955, the house itself was built in 1892. So we have an old house on top of a modern foundation which is a 4 foot high wall made of poured concrete and a 3-1/2 foot cinderblock wall on top of that
I'm currently in the process of applying an interior insulation strategy in my basement (located in the Northeast). Applying the insulation to the exterior would have been too costly, so I'm going with the next best thing. The strategy I've taken so far is to use Rigid XPS on the interior foundation block walls (taped at all seams) and have applied spray foam insulation to the rim joist cavities. The basement also has an interior drain system, with a gap between the foundation wall and slab to allow any moisture to drop down into the drain and ultimately get pumped out. After watching your video, I have a few questions that I hope you can help me out with: 1) The interior drain has a plastic, ribbed sheet that comes about 3" up out of the gap between the slab and foundation wall. I've been tucking the rigid board into this sheet and gluing the boards with vertical strips of adhesive so that any water potentially making its way between the foundation wall and XPS can drip downward into the drain, and ultimately get pumped out. However, I have not been sealing the bottom of the rigid board where it gets tucked into this plastic sheet. Should I put a bead of spray foam along this joint to air seal that area? and; 2) I have not yet applied any insulation to the top of the foundation wall - the XPS ends at the height of the wall and the spray foam was applied at about 2" thick to the rim joist cavity. So, there is exposed concrete block still at the top of the foundation, and part of the mudsill is also exposed. As you mentioned in your video, spray foamers usually seal that area up too making a continuous seal all the way down the wall, but based upon your video I'm starting to think it might be better to leave that area exposed and uncovered. Wouldn't that better allow any moisture moving upward through the wall to escape and dry to the inside, thus reducing the chance of moisture buildup in the rim joist assembly -- most notably moisture that could otherwise accumulate between the mudsill and foundation with nowhere to dry? There is no capillary break between the mudsill and the foundation wall, and adding one is cost prohibitive. On the flip side, leaving that area uncovered might also promote moisture in the warm interior air to condense on that exposed, cold surface thus creating a moisture issue and potential rot on the sill. This is one question that I've been particularly struggling with as I'm near to closing up the framing down there and want ot make sure I take the proper approach. What do you think -- leave the foundation top open or close it up with some more spray foam or XPS? Thanks in advance, and thank again for the great video.
Also note that the interior drainage system has holes drilled thru the foundation wall just below the top-slab level, which sit behind that ribbed plastic sheet. I assume these help any water in the wall to escape down into the drain and get pumped out, rather than accumulating in the wall. Given the drainage system in place, I am also assuming that the foundation wall should be fairly dry and thus would allow me to insulate the interior walls safely.
Jeff LeSauvage I'm curious about this -- is it common practice to have holes drilled into the foundation wall blocks to drain any accumulating water down to a interior perimeter drain tile system? It seems like a good idea, and I wonder if that would allow you to increase the insulation on the interior of the space because water that would form there would condense and fall to the system maybe?
The real moral of the story here is that you basically cannot safely insulate a basement from the inside in any manner using any materials if your sill plate is not separated from your foundation by a capillary break. All methods(fiberglass + plastic, XPS taped and caulked, or a full spray foam job), WILL drive the moisture into your sill and rim joist because they prevent inward drying. Either you seal off that sill from your concrete foundation or it is no deal of any kind.
I would measure moisture content in the concrete and act accordingly. If moisture content is low and there is plenty of opportunity to dry to the outside I would go ahead with interior insulation. If moisture content is high and little opportunity to dry to the outside then any interior wall system would have to be well ventilated to allow drying to the interior.
rain we get 100" rain and 30" fog with high humidity. Must drain water from house . French drain inside and outside. Moisture mat on outside wall to drain to daylight . In South must have bug inspection prior to sale or recommended to homeowner. Critter prevention moisture removal inside and out. What do you think of foam block inside and out ?
This is great information for New Construction. It doesn't offer a solution for homes when getting to the exterior is not possible. I guess I too have no choice but to bulldoze my home and start over.
I have efflorescense on my basement floor. It has a thin concrete slab with an air gap underneath, where the soil has settled. We put a roll-on moisture barrier and vinyl tiles. Almost immediately the problem became obvious, as it looks like ant hills under the tiles. Its a house in Toronto, On. built in 1928. One room has a ceramic tile floor and has no issues.
Well done! Being a perfect constructruction is near impossible. A better strategy is to use materials that are more perfect. The insulated concrete form and insulated slab on grade combine to give a simpler way to achieve perfection.
Amazing presentation. I'm still just a somewhat beginner to moderate DIYer and so I was hoping someone may still be monitoring this video's comments. I was hoping you might be able to give me the big picture view of what can we do to be the safest in an existing building that is an old house? For sure probably not a dry foundation although no evidence of leaks through the block foundation wall in the basement. I'd really like to do what I can. I obviously can't dig outside of the foundation to add anything exteriorly and don't want something ugly on the exterior. It sounds like maybe my best bet is rigid board insulation on the block walls and a small amount of spray foam in the rim joists?
For interior insulation you might use following strategy, it looks like it reconciles with physics described in this video: put dimpled membrane on the floor, plywood or OSB on top and screw it to concrete floor. This will take care of moisture coming from below. put 6 mil poly or better still dimpled membrane too on the wall all the way down to basement floor, and seal it to dimpled membrane on the floor: this will take care of incident water and water vapour through the wall. Because it is dimpled membrane, the air underneath it gets to Rh 100% and equalizes vapour pressure. Put regular frame on top with fibreglass insulation, but instead of using poly as vapour barrier on the inside, use variable permeability membrane like Certainteed MemBrain. It changes it’s permeability with change in RH: once RH goes above 60% it opens up, let’s water vapour through. So if you get some condensation inside the wall, variable permeability membrane will let it dry to the inside.
Good video, I have a daylight basement with no vapor barrier in the floor. The walls in main room are covered with 3/4 tongue and groove attached horizontally directly attached to foundation wall (3 foot hip wall) on top, 2x6 wall framing bat insulation r19, plastic barrier. cover T 1-ll. The wood stove takes care of all moisture. In another room foundation has a thin layer of joint compound and paint. No molding unless something blocks air to it. This room I have two layers of pile carpet, the ground is very cold. Your presentation is Correct. However the other room has thin industrial carpet and is very warm to my feet. I am going to do an addition, brainstorming the best design. I really like to go geothermal with Rocket stove. Search and brainstorm until the light goes on and you got it. Thanks
amazing video ...looks like you could just add or hang a common open weave fabric wall drape to decorate cellar with no problems as long as air gets thru. didnt do quite enough explaining on the drainage issue under the foam though if air gets in drainage channels will be wetting surface no ?
Interesting. I wonder if having vertical aggregate along side the outside basement wall might help keep moisture away from the wall, along with the exterior water sealing and insulation of course. It all looks like something we are still trying to figure out. Most of it though seems to say we need to seal and insulate the outside. There seems to need to be an escape route for moisture at the top of the cement wall so it does not get into the base of the framing. Probably best to use treated lumber at the base, if not plastic lumber. I will have to watch this again and take notes.
David Parker we did that in retrofit exterior drain tile jobs in new York, along with waterproof membrane and exterior insulation. expensive job, but dried the basement effectively every time.
EdwardSnowdon the black plastic dimple barrier would eliminate the need for you washed rock drainage idea Matt Risinger uses it with liquid applied blue 60 mil sealer on outside concrete wall of basement
Excellent tutorial and model! I have 3.5 questions for the speaker. First, What product or type of insulator is best suited for the exterior of the foundation wall below grade? Also, is a secondary protective layer recommended to the outboard side of that insulation layer? Secondly, in regard to the V-groove style footing shown- is the rebar grid within the foundation wall to be isolated from the footing (due to the waterproofing applied to the top of the footing)? Third, If ICF systems are being utilized below-grade, what precautions might the builder use to prevent the exterior polystyrene layer from being compromised from a puncture/moisture infiltration perspective? Thanks again!
Hi! Here is what University of Minnesota Extension specialist Pat Huelman had to say about your questions "I am generally most comfortable with XPS (extruded polystyrene), but semi-rigid fiberglass boards can work, too. If there is true waterproofing behind the insulation and good vertical drainage in front, a secondary layer shouldn't be necessary. It is OK to use rebar to pin the foundation to the footing (rather than a keyway) just work the liquid applied capillary break around the pin. If an ICF is used, it still requires an exterior water control layer (generally a foam compatible waterproofing membrane). This can provide some protection from physical damage, too. Hope this helps"
Great video even if I intuitively assumed most of what u said was the case. It's good to have confirmation my assumptions were correct. And the importance of a vapor barrier between foundation or basement wall and the rim joist was not even a consideration, So that was very enlightening. But I hope u have or will have videos on Aircrete or ACC (Autoclaved Aerated Concrete) or any related building material since it seems to have so many advantages vs its disadvantages. For a building material developed in the 1920s its a shame its taking so long to be used on wide scale. And the fact its still not used that widely used in the US is real shame
Nice video, so what is someone with an older home to do? Is exterior insulation and waterproofing the only and best answer? It seems like and expensive proposition. Are there other alternatives that are effective?
Interior spray foam works. Some caveats: most need to be covered for fire protection. In a very cold climate, the foundations will freeze and if full of moisture, can heave and crack.
This is an interesting video that made me believe the "main culprit" in managing the issues of water, vapor, air, and heat is the use of concrete! With all the "space age technologies" available, what would be a better solution for foundations as opposed to using 100+ year-old technology of concrete blocks and mortar? (cost aside)
Great presentation, learn a lot ! ...quite depressing thou if trying to make a dry, moisture free, thus mold free basement walls :) ...also, sounds like you can not have anything on the basement floor :)
If you already have a damp basement and only want to dry it out first clean up the basement (IE no stuff leaning against the walls) and run an osculating fan 24/7. If you want to dry it out and put up drywall then you need to address water infiltration first.
Well ! Thank you sir for this very clear and scientific explanation of insulation performance, including thermal and moisture control in a building envelope. I see this on this day March 25/2020, eight years after the production of this information and this is still new information it seems to me as I have been for many months inquiring of "professionals" how to properly insulate my older (1948) home. Those I have queried have not understood what you have so clearly, eloquently and correctly described and explained. The explanations i had been offered left me thinking something was not quite right. I now know how to correctly proceed. See Lok Tom's comment from 2 months prior. Kidding. Great information and thank you Mr. Huelman.
After watching this well presented video, I have to bulldozer my old house.
lmao
Ohh not a good news 🤣
I was thinking of burning mine but apparently I have too much water vapor for it to catch fire.
Indoor pool might be an option..
Hilarious. I thought id get some good ideas on how to fix some problems and finish projects my dad started but never got to finish himself and eight minutes in im thinking well damn, guess i will have to start at the ground and just replace all the entire foundation....and redo the walls and siding....and...hmmm maybe just move away
this is one of the best explanations of the mechanics and difficulties involved with insulating below grade walls in northern climates. well done.
This video should be required reading/viewing for anyone buying a home with a basement or building a new home with a basement. The very best in depth analysis I have seen.
It’s actually not relevant anymore
@@CMCraftsman Just finished watching this video and wonder if it was still relevant anymore. Where are you getting the latest and greatest information?
This certainly is one of the better YT videos I watched and learned so much information about proper foundation/slab assembly and "why" one should construct this way. Also having a real-life mock-up with labels, pointing and demonstrating helps a ton!! Very well done sir!
Excellent information! I am just beginning to plan my future home build here in Ohio and after reading 100s of articles and watching 100s of videos on building science strategies, I've learned that the most important thing to get right, by far, are the 4 envelope control layers (water, vapor, air, thermal). If you spend an appropriate amount of the budget on getting the envelope right, you will absolutely prevent problems down the road AND get a more comfortable house, overall. I've decided to go all out with my envelope and try to save some money on aesthetics, which can always be upgraded later. It's the structural details that should never be overlooked during initial construction because they're not easy to fix later.
Wow Pat, this is the best video explanation I've found, and I'm 65, so I've seen many. Thank you Sir for sharing this knowledge of yours so simply & understanding to us. The enigma is over... Cheers :)
This is the most thorough-going, understandable presentation on foundation moisture management that I've ever seen. The information here could save you tens of thousands of dollars.
More likely save the next owner tens of thousands of dollars.
PROFESSOR, THANK YOU FOR GIVING US THE GIFT OF YOUR KNOWLEDGE AND TIME!
Thanks so much, i need to show this to the builder doing my addition w/ crawlspace.
I'm owner-building my first home in Anchorage, Alaska. This is by far the most helpful video I've found on how to build an effective cold-climate foundation. Thanks a ton for the work in putting this together.
Hi Paxson! How did the build go and did you insulate from the outside!??
I'm wanting to build in northern Ontario and looking to build foundation and walls of bungalow with block. No lumber but the floor and roof
Your feedback and experience would be a huge plus.
Thanks!
Mike
5 inches of XPS on the exterior, over a layer of Ames Bluemax. I’m sure it will work nicely if I ever finish the house…
@@PaxsonWoelber Thanks for the insight. Not familiar with the layer of Ames but I'll look into it. Thanks again!!
@@PaxsonWoelber how's the house? I'm a carpenter building my own finally here in Michigan
@@mattmag3089 the project was disastrous, unfortunately. The GC I hired to frame the house did such a bad job we ended up having to tear the house down. The project is in limbo and I'm renting now.
I learned a lot from this expert. I have been a Framer in Calgary Canada for over 10 years. I am going to take a 3 year course next Fall called Energy Systems Engineering Technologies. Thank you Mr. Expert, Great video.
Did you take that course? How did it work out?
@@ryanshannon6963 TV Ontario did a whole series called "R-2000 The Better Built House". If you can find it its well worth watching. This series covered the proper installation of air and vapour barriers that hardly any builders or renovators follow or understand.
What I found was that builders would take the course and then get R-2000 certified on one house, and then go back to their old practices claiming their houses were R-2000 compliant. I was trimming one of these houses and the air was blowing right in under the bottom plate of the wall assembly proving they had not sealed the envelope of the house properly.
Very informative and you saved me a pile of money, I was thinking of finishing the basement but after seeing how it's nearly impossible to do without problems I said forget it.
Absolutely enlightening explanation. Many thanks to Pat Huelman and the rest of the folks involved in the production of this valuable content.
This is one of the best videos for the fundamentals of understanding what the heck is going on with insulation in a building I’ve seen. Solid recommend, 10/10 almost certainly will watch this again. Thank you for making this content available!
One thing to keep in mind is that if you insulate a concrete basement or even slab on grade from the outside. You are giving the house a huge thermal mass. An other way say thermal mass is a thermal reservoir because it is a mass that stores hot or cold. This thermal reservoir will make a huge difference in emergence situation where the house looses heating. The warm "indoor" concrete in the basement will keep the home warm probably for several days if not a week even with extreme conditions outside if the house is properly insulated.
I agree... did project where the engineer had no insulation under the basement floor slab (just a really good moisture barrier) he claimed that the earth under the slab becomes part of that thermal mass as you explained...
The best explanation of insulation issues I've ever seen. Thank you.
That’s fine for a new build but what about a remodeling of your basement
Great video to educate people in the construction business as well as homeowners. It's often hard to sell clients on proper building methods to prevent potential issues like mold to develop in sealed tight homes. ICF seems to be a good alternative method to constructing a basement.
Outstanding video! I've now decided to build my house on stilts.
Ive watched tons of videos on insulating and framing basement walls. This is the first that makes it truly understandable and its a very in depth video. Thanks!
For the exterior looks, there is rigid foam with a stone veneer that can be used where it may be exposed.
This is a fantastic video. As a first time home buyer trying to understand the fundamentals of building science so I can better choose a home, this is invaluable. Thank you for taking the time to put this together!
Great video, thank you for the education. I have learned so much more here in 30 minutes than all my discussions with contractors and building suppliers! Best regards.
Sir. I can't thank you enough. Just perfect you and your colleagues well done! Answers to questions I didn't quite have yet. Everyone needs to see this first!
Most informative insulating video I've had the pleasure of finding yet!
Thank you for this video. My house was built about 17 years ago; I have owned it just 2 years. I was going to finish the basement but ran out of money since I totally renovated the upper floors. Instead I applied DryLok Extreme - 2 coats covered by SW reflective white paint. The walls were reinforced poured concrete with a brick pattern on both sides. If anybody is thinking of this - use Thro Seal and save your shoulder. Both are "pulled into the concrete" and virtually impossible to roll due to the brick pattern. The floors were painted with two coats of SW concrete paint. NO dampness, not cold? I dug around the foundation and found the builder had tarred the foundation, covered it with a mesh, a second coat of tar and then applied 4" of rigid foam insulation. A Swiffer is all you need to maintain the basement. After this video I understand why the contractor put that insulation on the OUTSIDE. I don't have to think twice about off-gassing.
I intuitively knew that placing the insulation outside was a much better option but when my parents had their house built they did what the builder recommended and placed it on the inside house. And I inherited the house. This video post just reminded about the costly mistakes made building it,
As side note I would use Aerated Concrete (it just has so many advantages and only a few disadvantages) and use a robust vapor/moisture barrier system if I would ever have a house built at this point,
But since megatition is the only option for this house. My choice will probably be the less costly and less effective interior megatition option since digging around the whole house seem like it will be to costly for moderate moisture issue that I have experienced. Good luck finishing ur project too.
So it goes to prove the old expression is correct "an ounce of prevention is worth a pound of cure"
Wish I would have found this 3 years ago BEFORE I built a new cabin in Northern Wisconsin. This video is at least 10 years old, why isn't this more common info by now and hasn't been adopted / required by the building practices. I insulated inside with 1" foil faced placed tight to the foundation wall, foil side facing in. Taped all seams. Then built my 2x4 framed wall and added 2" foam sheets to the wall cavity. Hindsight, I would have placed both 1" and 2" behind the wall framing to make running electric easier. I would have only lost a total of 4" in overall length and width of the basement, been able to attach full sheets of insulation. Great information... maybe next build... if I ever do.
This is the best information on moisture and insulation in a basement I have ever seen! He address the complicated relationship between moisture movement and heat movement. Thank you, thank you, thank you
Fantastic, well thought out video. Thank you. Q: We've just poured our basement walls. Footer rests on natural undisturbed ground (mostly though there are slight gaps here n there under the footer form, they were filled with concrete that spread out a bit. Footer was a very tight, stony mix) The walls were a looser mix and our contractor has never used a capillary barrier and even after asking for it, it was "forgotten" and so the walls are up and in forms over the long weekend. Our footer drain is in its own ditch alongside the footer and about 1/2 of it's diameter below the footer bottom and out from the footer about 4", completely filled with clean stone to the top of the footer. The plan is for 2" xps and a dimple board outside of that with native fill against that. A plastic barrier up the wall a foot above the footer, behind foam board, down and across the top of footer and onto the clean stone above the drain. There will be a ditch drain at the surface with clean stone and a 4" perf pipe, tied by vertical "downspouts" into the footer drain. Because of siding overhang issues with builder we've agreed to not take the insulation up over the rim joist. Rather, the foam and dimple board will end at top of fndn wall and we will spray-foam that rim-joist void from the inside. My understanding is the spray foam will not allow for vapor trapping and so will not be a major source of heat or vapor transfer. And, no mold. So the only place we're not good here (I think) is that vapor up through the footer. Since this is how homes have been built for so long, my questions are (science aside, I'm sold that it should have been done) just how big of an issue could this be? What can be done now to mitigate it and, would it be cost effective?
I'm in your same position (though you have a better plan at this point). Can you share what you did?
This could be a very BIG issue depending on you ground/soil conditions. If you have issues or are concerned that you may have issues with water/vapor up through the floor/footer I would recommend a second drain tile on the interior side of the footing draining to a sump pump.
The overall point is to make sure your basement wall and floor have been properly waterproofed/damp proofed from the outside. After this is done insulate from inside, especially top portion of concrete wall where it is exposed to cold air. (North climate).
A dehumidifier is a good to have too.
Umm no , he makes it. Rey clear you insulate from the OUTSIDE!!!
Excellent video. The building science approach will always trump the "in my experience" approach.
Pat Huelman : very informative to the non skilled builders out there. An additional approach based on that you don't build where a natural swimming hole exists is if possible build higher out of the ground and back slope to move water away naturally from the foundation while still implimenting all the details that you have shown. In addition if the backslope is not too extreme a piece of poly plastic can be placed 4 to 6 inches under the soil slope to move surface water dramatically away from the building and possibly the outer edge of the plastic drainage slope intersecting a french drain there by keeping a large dry mass of soil surrounding the building.
This is a great video. Admittedly, the more I learn about basements, the more I lean towards: "I think when I build, that I don't want a basement."
Basements are fantastic though - for all kinds of reasons including a nuclear bunker! lol! I want a basement but man its stupid expensive to build properly and for the long haul.
I get it but the thing is if you need frost protection a basement is ideal and the cheapest way to expand livable building space. I’ve had a few houses with basements and they’ve done well.
@@patty109109 I happen to live in an area where flooding is an issue even for above ground dwellings. And also it freezes. Maybe I need to move lol.
Am glad to see someone finally talking so much about Moisture. I basically deal with retrofit so there is usually no water proofing in the homes I come across. The only solution I could add for folks is to spray on Penetrating Concrete Sealer onto inside concrete block foundation walls and cement slabs. This doesn't quite get the footing sealed, spraying from the inside so I often dig up outside perimeter and spray the footing then exterior foam.
Just wanted to offer penetrating sealer option
Excellent! Real explanations. No sales pitch. Let it breath!
The external insulation combined with the making it look pretty on the outside, is making a perfect channel for termites to get into your house without you ever knowing it.
Wow! Mr. Huelman, what a wonderful presentation on the nuances of foundation design and management. It was very informative. Thank you for your knowledge and clarity.
This feels like the presentation for ICF foundation systems. Checking most if not all of the boxes when paired with a perc outer wall treatment & slab assembly.
icf ftw
Excellent! Just wish you showed exterior insulation using other products like mineral wool, or graphite polystyrene. Keep in mind that foam products make great nesting material for insects, even below grade. I've seen insects in foam in northern Michigan, it is not just a hot/warm climate issue. Thanks for the excellent videos on the subject of below-grade insulation.
Yes my foam has holes in it and the parging fell off
Great video. Pat touched on so many issues but was superficial on some critical parts of the waterproofing system.
From over 20 years of experience I can add that the most important part of the waterproofing system is the exterior drain tile. 99% of all drain tile installation on new construction are done pretty quickly with almost no effort to paying attention to making sure the tile is completely clean of any foreign matter. You can waterproof using the Ferrari of systems but if you have a clogged or obstructed tile system water can and will go through; it's not a boat. Also I think the worst method of waterproofing a basement from the interior is to use spray foam (closed or open cell). The reason for that is that moisture is standing on the outer side of the foam waiting to infiltrate and has no way of trickling in any direction because it's essentially glued to the concrete. Concrete can and will crack in turn cracking the insulation with it since it's glued to it. Now you have a huge problem because you have a channel of water infiltrating all the water from all sides. I've seen it it's not theory it's experience. NEVER use foam. Basically the best system is the driest system. Follow gravity and concentrate on the bottom part. Drain tile, sump system, a good pump kit will give you a comfortable basement even with minimal bells and whistles. Again it's a great video thank you for posting it.
your thinking is compartmentalized...your experience simply sheds light on improper installation and techniques from construction jokers...no disrespect
mark drysdale I'm sure you'd be the historical reference on the marvels of Aristotele, Leonardo da Vinci, Michelangelo and the likes. We're eternally grateful for your precious thinking and input.
There is some good "stuff" which looks like a dimpled fabric that is put over the tarred foundation and goes down to the drain tile. The drain tile is covered with a silt cloth and in my prior house has a clean-out at ground level so I can get a hose in there to wash out the silt - which I never had to do. My downspouts all fed into a 6" schedule 40 rigid pipe that ran to light about 40" from the house. This house has some of the same features but the external drain runs to the storm sewer. I also have 3 sump pumps: 1) a grinder pump so I can add a toilet down there if I want; 2) a regular sump pump and 3) a water powered back-up sump pump. I sealed all the sump pumps because there is radon in the soil around here and while I don't have a problem I just wanted the protection. If you have enough space, burying the "horizontal" pipe that collects the gutter water is the best solution. My basement is not damp, cold or musty.
I have a 100 year old house with quadruple wythe brick walls in the former coal cellar Basement but a poured foundation and no drain tiles. I couldn't get to the exterior wall without digging up my neighbors entire yard. I parged the imside walls of the one leaky side (wasnt that leaky) of the Basement, glued up foil faced polyiso on all 4 walls from floor to rim joist using like 50 tubes of PL Foam adhesive, which has no initial grab, but is great after a week (literally a week). Then furred that out with PT 1×4 16"OC vertical, then Horizontal. Drywalled with greenboard and tiled the floor. I'm slow as molasses and had a kid in the middle. Took me 2 years to finish (did a bunch of electrical and plumbing upgrades in middle plus jackhammered floor and poured piers with which I jacked up kitchen on lally columns), ANYWAY 5 years afterward - Amazingly - no water. No moisture problems. Split it into two rooms: office and laundry room. Polished a HUGE TURD and has worked out well for us. People thought I was crazy.
When one thinks about it, when you're in the frozen North, you don't eat your winter parka. The parka works best on the OUTSIDE.
And I think I read where Mt Everest climbers learned to put vapor barriers on the INSIDE of their sleeping bags to prevent their moisture from freezing halfway out. Always place the vapor barrier on the side with the greatest vapor pressure.
This video is great at explaining the best way to insulate a home in the Northern states. Best done on new construction though...
Super appreciated the explanation. Definitely just saved me a lot of time and money before I started my project.
Hello Pat and thank you for one of the most informative videos on this subject.
Question: Though I have no water issues in my below-grade block walls, I still applied UGL's Drylock Waterproofer to the walls as an added measure. Next, I built a stud wall, keeping the studs about 1/2" from the block wall, and insulated with unfaced fiberglass insulation. Then I applied Certainteed's "Membrain" to the inside of the stud wall. The Membrain repels vapor from the inside of the basement (keeping vapor from getting into the insulation) and allows vapor in the insulation (if any) to permeate inward to the inside of the basement. 1/2" Water/Mold Resistant drywall was used as the inside finished wall. Aside from your concerns about a water event that could soak the drywall or fiberglass insulation (though possible, is not likely in my case as I have pretty good drainage in the basement), do you feel that what I've done is adequate? I should also add the I have added two intake vents to the basement that draw air to the heating and cooling system. There were no intake vents there before and the basement only had a very small area of mold growth behind a large cabinet placed next to the wall.
Thanks, Steve
I thought this was really well done and super informative. Thank you very much for the education.
I have lived in a all brick 1908 home for 38 years. After spending a lot of studying this issue and radon gas. I chose to let it brick breathe some air leaks up a wall into the attic. The benefit for me is a much lower radon gas, dehumidifier and a higher heating and cooling cost. But I know the home is much better air quality.
This master professor is my hero and ofcourse the video creator.
I wish I can find other masters with relative ease in other not so related industries and learn scientific theories, evidence and so forth.
Thank you to both of you for putting out this article.
Yes a house completely foam board insulated and made air and water tight everywhere on the outside is the ideal home. All new construction should use this technique.
This was a really in depth explanation. Thank you so much, I will watch again during construction. Thanks
Praise Jah
Imagine if we had this good a teacher and this good a video on every topic
This is probably the most important videos on this topic Everyone should have to watch this first before watching all those crazy ideas out there. The one slip I heard was when he used the word Polyiso,(26:32) which I would not recommend on a wall as it can become a vapor trap for moisture.
1942 cape in hamden, ct. Just doing closed cell between crawlspace cedarblock and floor joists, then spray foam around corners.
2 years of listening to so many video's without answering the problem i am experiencing. At 6 minutes, approx 20 seconds, you are the 1st to give me the answer. Plus, at 28:24. Right now the corner of my house has been dug by tractor shovel to the drain. I removed the 1 inch fiber insulation that was soak & wet, why do they use this stuff? Gets wet and freezes. We get minus 45 Celsius/Fahrenheit temps. That made the inside wall sweat so much behind the pink insulation, that i had a ice buildup of up to 1/2 inch inside. Though i had water coming in from roof... thank you for this amazing video. I will share it at large. Cheers. PS: any other suggestions, feel free to let me know please. Going in to do the work in couple/few days after rain stops. The water table is very high here.
Very informative and extremely well done. Thank you.
Great video. I'd like to suggest that a basement wall with insulating batts should employ rock wool instead of fiberglass. Rock wool is hydrophobic. It will not absorb or hold water even if exposed to liquid water. So, in the event of a flood or plumbing disaster, it would not have to be dried out. Perhaps the wood wall construction would need a little drying. Your drywall will be cashed and need to be removed anyway.
Rock wool will also inhibit mold growth due to its inability to hold water.
What opinions do you have about products that supposedly "seal" concrete such as RadonSeal?
Rock absorbs water like a sponge. Once wet has no insulation factor.
Blue or pink board is the best bet or a closed cell spray foam.
Rock wool
I demo imsulation alot and get several questions about basements. I'll send the people to this video it should help them out alot.
This video should be watched by every builder and remodeler.
Not just watch it, Pay attention. Who knows how they finished up the job, late Friday afternoon, just wanting to get to the bar! No one knows whats behind that dirt once backfilled.
Amazing how much has changed in 12 years.
Like what?
Finally a great video on basement insulation! thank you for sharing this, very informative!
Very well explained, I now know better on what to do with my foundation. Cheers.
After a few weeks of youtubing and gooogling this topic this is the best presentation of information I've seen. Thank you.
Thank you for that video. I'm assuming that on existing homes where the outside has not been insulated, that you are left with no other choice than to insulate, and vapor barrier the inside foundation wall ? ...or would you still leave it alone and take the heat loss in exchange for risk aversion to moisture buildup ?
I just got crash-coursed on foundation insulation.
And I guess I now know how to tackle my mold problem.
Thanks guys
One of the best explanations on foundation insulation and moisture mitigation I have seen. I now better understand how and why my 32 year old concrete block foundation does what it does. I have efflorescence on the walls, mostly at the bottom course and the top few, exposed to outside air. The foundation was waterproofed with a product called Theroseal. It adhered and held up quite well on the outside foundation walls but unfortunately does not have good waterproofing properties. It probably would have been better to just use an asphalt coating. If I were to build a home today I would certainly use the techniques described in this video.
Now if I could just find a way to stop the efflorescence on the inside walls. The last product I tried on some of the virgin walls was a product called Hydro-seal 75, an epoxy paint product. Now after about a year the efflorescence is pushing the paint off the walls. It works great on the areas where there was no efflorescence.
Outstanding video that offers exceptionally useful information and advice. Thank you!
Great video, thanks for sharing:)
I'm curious as to what you would recommend as the best insulation and install if you had no choice but to insulate a basement from the inside?
Sounds like you shouldn't use insulation on the interior. It's below grade anyway so it already is insulated to a certain degree.
Have a contractor dig down to the footings on the outside and water proof and insulate. Expensive? Yup, but it's the best way.
Our house was moved to it's present location in 1955, the house itself was built in 1892. So we have an old house on top of a modern foundation which is a 4 foot high wall made of poured concrete and a 3-1/2 foot cinderblock wall on top of that
I'm currently in the process of applying an interior insulation strategy in my basement (located in the Northeast). Applying the insulation to the exterior would have been too costly, so I'm going with the next best thing. The strategy I've taken so far is to use Rigid XPS on the interior foundation block walls (taped at all seams) and have applied spray foam insulation to the rim joist cavities. The basement also has an interior drain system, with a gap between the foundation wall and slab to allow any moisture to drop down into the drain and ultimately get pumped out. After watching your video, I have a few questions that I hope you can help me out with:
1) The interior drain has a plastic, ribbed sheet that comes about 3" up out of the gap between the slab and foundation wall. I've been tucking the rigid board into this sheet and gluing the boards with vertical strips of adhesive so that any water potentially making its way between the foundation wall and XPS can drip downward into the drain, and ultimately get pumped out. However, I have not been sealing the bottom of the rigid board where it gets tucked into this plastic sheet. Should I put a bead of spray foam along this joint to air seal that area? and;
2) I have not yet applied any insulation to the top of the foundation wall - the XPS ends at the height of the wall and the spray foam was applied at about 2" thick to the rim joist cavity. So, there is exposed concrete block still at the top of the foundation, and part of the mudsill is also exposed. As you mentioned in your video, spray foamers usually seal that area up too making a continuous seal all the way down the wall, but based upon your video I'm starting to think it might be better to leave that area exposed and uncovered. Wouldn't that better allow any moisture moving upward through the wall to escape and dry to the inside, thus reducing the chance of moisture buildup in the rim joist assembly -- most notably moisture that could otherwise accumulate between the mudsill and foundation with nowhere to dry? There is no capillary break between the mudsill and the foundation wall, and adding one is cost prohibitive. On the flip side, leaving that area uncovered might also promote moisture in the warm interior air to condense on that exposed, cold surface thus creating a moisture issue and potential rot on the sill. This is one question that I've been particularly struggling with as I'm near to closing up the framing down there and want ot make sure I take the proper approach. What do you think -- leave the foundation top open or close it up with some more spray foam or XPS?
Thanks in advance, and thank again for the great video.
Also note that the interior drainage system has holes drilled thru the foundation wall just below the top-slab level, which sit behind that ribbed plastic sheet. I assume these help any water in the wall to escape down into the drain and get pumped out, rather than accumulating in the wall. Given the drainage system in place, I am also assuming that the foundation wall should be fairly dry and thus would allow me to insulate the interior walls safely.
Jeff LeSauvage I'm curious about this -- is it common practice to have holes drilled into the foundation wall blocks to drain any accumulating water down to a interior perimeter drain tile system? It seems like a good idea, and I wonder if that would allow you to increase the insulation on the interior of the space because water that would form there would condense and fall to the system maybe?
@@uncertainscientistmy last house the very bottom course had some mortar missing between the CMUs to support this kind of water movement.
This is by far the best video I have seen on this topic.
A great solution to most of not all of those problems, closed cell spray polyurethane foam. Below slab, exterior basement walls, rim joist, etc.
Form-a-drain footing and ICF with membrane barrier.
Thanks for sharing this. I'll have to view several times to absorb it all.
Pun intended?
I've been looking for this video and this information for some time. Thank you👍
This video was just what I needed to watch. Thanks a lot for all the info.
Unbelievably helpful. Thank you so much for this.
The real moral of the story here is that you basically cannot safely insulate a basement from the inside in any manner using any materials if your sill plate is not separated from your foundation by a capillary break. All methods(fiberglass + plastic, XPS taped and caulked, or a full spray foam job), WILL drive the moisture into your sill and rim joist because they prevent inward drying. Either you seal off that sill from your concrete foundation or it is no deal of any kind.
Aezelll I was thinking that, then saw your comment. idk what to do about it now.
I would measure moisture content in the concrete and act accordingly. If moisture content is low and there is plenty of opportunity to dry to the outside I would go ahead with interior insulation. If moisture content is high and little opportunity to dry to the outside then any interior wall system would have to be well ventilated to allow drying to the interior.
rain we get 100" rain and 30" fog with high humidity.
Must drain water from house . French drain inside and outside. Moisture mat on outside wall to drain to daylight .
In South must have bug inspection prior to sale or recommended to homeowner. Critter prevention moisture removal inside and out. What do you think of foam block inside and out ?
This is great information for New Construction. It doesn't offer a solution for homes when getting to the exterior is not possible. I guess I too have no choice but to bulldoze my home and start over.
I learned from my mistake and this video confirmed it. Thank you for a great explanation!
I have efflorescense on my basement floor. It has a thin concrete slab with an air gap underneath, where the soil has settled. We put a roll-on moisture barrier and vinyl tiles. Almost immediately the problem became obvious, as it looks like ant hills under the tiles. Its a house in Toronto, On. built in 1928. One room has a ceramic tile floor and has no issues.
Well done! Being a perfect constructruction is near impossible. A better strategy is to use materials that are more perfect. The insulated concrete form and insulated slab on grade combine to give a simpler way to achieve perfection.
Excellent! I appreciate your time and effort and for your sharing of such valuable knowledge.
Amazing presentation. I'm still just a somewhat beginner to moderate DIYer and so I was hoping someone may still be monitoring this video's comments. I was hoping you might be able to give me the big picture view of what can we do to be the safest in an existing building that is an old house? For sure probably not a dry foundation although no evidence of leaks through the block foundation wall in the basement. I'd really like to do what I can. I obviously can't dig outside of the foundation to add anything exteriorly and don't want something ugly on the exterior. It sounds like maybe my best bet is rigid board insulation on the block walls and a small amount of spray foam in the rim joists?
Thanks for an incredible presentation !
Fantastic job by this dude. Cheers...
For interior insulation you might use following strategy, it looks like it reconciles with physics described in this video:
put dimpled membrane on the floor, plywood or OSB on top and screw it to concrete floor. This will take care of moisture coming from below.
put 6 mil poly or better still dimpled membrane too on the wall all the way down to basement floor, and seal it to dimpled membrane on the floor: this will take care of incident water and water vapour through the wall. Because it is dimpled membrane, the air underneath it gets to Rh 100% and equalizes vapour pressure.
Put regular frame on top with fibreglass insulation, but instead of using poly as vapour barrier on the inside, use variable permeability membrane like Certainteed MemBrain. It changes it’s permeability with change in RH: once RH goes above 60% it opens up, let’s water vapour through. So if you get some condensation inside the wall, variable permeability membrane will let it dry to the inside.
15 mil poly is what I've seen elsewhere.
Good video, I have a daylight basement with no vapor barrier in the floor. The walls in main room are covered with 3/4 tongue and groove attached horizontally directly attached to foundation wall (3 foot hip wall) on top, 2x6 wall framing bat insulation r19, plastic barrier. cover T 1-ll. The wood stove takes care of all moisture. In another room foundation has a thin layer of joint compound and paint. No molding unless something blocks air to it. This room I have two layers of pile carpet, the ground is very cold. Your presentation is Correct. However the other room has thin industrial carpet and is very warm to my feet. I am going to do an addition, brainstorming the best design. I really like to go geothermal with Rocket stove. Search and brainstorm until the light goes on and you got it. Thanks
amazing video ...looks like you could just add or hang a common open weave fabric wall drape to decorate cellar with no problems as long as air gets thru. didnt do quite enough explaining on the drainage issue under the foam though if air gets in drainage channels will be wetting surface no ?
Interesting. I wonder if having vertical aggregate along side the outside basement wall might help keep moisture away from the wall, along with the exterior water sealing and insulation of course.
It all looks like something we are still trying to figure out. Most of it though seems to say we need to seal and insulate the outside. There seems to need to be an escape route for moisture at the top of the cement wall so it does not get into the base of the framing. Probably best to use treated lumber at the base, if not plastic lumber.
I will have to watch this again and take notes.
David Parker we did that in retrofit exterior drain tile jobs in new York, along with waterproof membrane and exterior insulation. expensive job, but dried the basement effectively every time.
EdwardSnowdon
the black plastic dimple barrier would eliminate the need for you washed rock drainage idea
Matt Risinger uses it with liquid applied blue 60 mil sealer on outside concrete wall of basement
When I was in the Seabees a structural engineer explained a proper foundation or basement wall as, "an inside out swimming pool"...
What about termite inspection in those areas that have insect issues? Great video.
I've heard that Termites and Carpenter Ants like foam insulation.
Excellent tutorial and model! I have 3.5 questions for the speaker. First, What product or type of insulator is best suited for the exterior of the foundation wall below grade? Also, is a secondary protective layer recommended to the outboard side of that insulation layer? Secondly, in regard to the V-groove style footing shown- is the rebar grid within the foundation wall to be isolated from the footing (due to the waterproofing applied to the top of the footing)? Third, If ICF systems are being utilized below-grade, what precautions might the builder use to prevent the exterior polystyrene layer from being compromised from a puncture/moisture infiltration perspective? Thanks again!
Hi! Here is what University of Minnesota Extension specialist Pat Huelman had to say about your questions
"I am generally most comfortable with XPS (extruded polystyrene), but semi-rigid fiberglass boards can work, too. If there is true waterproofing behind the insulation and good vertical drainage in front, a secondary layer shouldn't be necessary. It is OK to use rebar to pin the foundation to the footing (rather than a keyway) just work the liquid applied capillary break around the pin. If an ICF is used, it still requires an exterior water control layer (generally a foam compatible waterproofing membrane). This can provide some protection from physical damage, too.
Hope this helps"
Great video even if I intuitively assumed most of what u said was the case. It's good to have confirmation my assumptions were correct. And the importance of a vapor barrier between foundation or basement wall and the rim joist was not even a consideration, So that was very enlightening.
But I hope u have or will have videos on Aircrete or ACC (Autoclaved Aerated Concrete) or any related building material since it seems to have so many advantages vs its disadvantages. For a building material developed in the 1920s its a shame its taking so long to be used on wide scale. And the fact its still not used that widely used in the US is real shame
Excellent video. I would like more information about systems to protect exterior foam board insulation above grade please
Thanks! Very clear and concise information-based video.
Nice video, so what is someone with an older home to do? Is exterior insulation and waterproofing the only and best answer? It seems like and expensive proposition. Are there other alternatives that are effective?
Interior spray foam works. Some caveats: most need to be covered for fire protection. In a very cold climate, the foundations will freeze and if full of moisture, can heave and crack.
Just outstanding! Thank you for the informative video.
This is an interesting video that made me believe the "main culprit" in managing the issues of water, vapor, air, and heat is the use of concrete! With all the "space age technologies" available, what would be a better solution for foundations as opposed to using 100+ year-old technology of concrete blocks and mortar? (cost aside)
Thank you for this, you probably saved me tens of thousands in mistakes waiting to happen.
My house was designed with interior insulation.
Need to send my architect this video.
Yes, Great presentation! Let this be the bible of the northern mixed climates!
Great presentation, learn a lot ! ...quite depressing thou if trying to make a dry, moisture free, thus mold free basement walls :) ...also, sounds like you can not have anything on the basement floor :)
If you already have a damp basement and only want to dry it out first clean up the basement (IE no stuff leaning against the walls) and run an osculating fan 24/7. If you want to dry it out and put up drywall then you need to address water infiltration first.
Well ! Thank you sir for this very clear and scientific explanation of insulation performance, including thermal and moisture control in a building envelope. I see this on this day March 25/2020, eight years after the production of this information and this is still new information it seems to me as I have been for many months inquiring of "professionals" how to properly insulate my older (1948) home. Those I have queried have not understood what you have so clearly, eloquently and correctly described and explained. The explanations i had been offered left me thinking something was not quite right. I now know how to correctly proceed. See Lok Tom's comment from 2 months prior. Kidding. Great information and thank you Mr. Huelman.