Closed cell is much higher in R-value but it's 2-3x the cost. I highly recommend it if you need it for additional structural properties (Hurricane resistance for example) but I use it mainly for below grade applications. No doubt it's the top-of-the-line foam, but it's hard to budget for frankly. Thanks for being a faithful subscriber! Best, Matt
Richard is spot on here. You need to read the ICCES report from the manufacturer of the foam you spray to determine what/if you need an ignition barrier. A few foams meet the spec without adding an ignition barrier, so require it. An easy ignition barrier is an intumescent paint. That's my typical final step in attics when necessary. Matt
Joe, They trim the foam flush to the studs. This is open cell foam so it's pretty soft/easy to trim. It's hard to say on cost for a 2000sf house but it's likely $5-8k with the specs you are seeing in this video. Costs vary widely depending on the region and availability of subs who are foaming daily. The busier the foam crew the better the installed costs I've found. Best, Matt
Yes I've seen that happen. It seems to occur most when the foam can't stick on three sides of a stud bay. For instance, if you were spraying against a cardboard or plastic vent inside a rafter bay where it only adheres to the 2x rafter on two sides but not on the back of the OSB/Plywood. It can also happen if conditions aren't right (mix, temp, etc). With a trained crew this is less a concern. Best, Matt
Conditioned attic space...outside temp 100, 74 in room and 76 in attic?!!!! I'm drooling at the thought. Damn it Matt, your vids always make me want to have a new house built!
Gary, It's hard to estimate payback but it could be very likely that it's a 10+ year payback. Retrofits are tough and expensive. The payback is much sooner if you are looking at new construction. Your money might be better spent on an Energy Audit by a BPI certified rater. Hire an independent auditor that doesn't work for an insulation company. They can identify "low hanging fruit" to upgrade. It may be better in terms of payback to upgrade your HVAC, tighten your leaky ducts, or...
Spray foam is definitely more expensive than traditional insulation but it's well worth the cost upgrade. With the air sealing benefits, the increased effective R-value, and the ability to insulate areas that can't be insulated effectively with fiberglass I think foam is tough to beat. Costs have come down in Austin because it's being used a lot so subs are busy. The materials are expensive, the machinery needed to spray is expensive, and the upkeep on the machines is expensive. Best, MR
Good luck in your searches! Matt is always so helpful, keep up the Great work with the videos about Building Science!!! Yes I LOVE the term Building Science, because that's what it is. Have a Great Weekend!
Great video blog. And even better job completed by the spray foam contractor. The SPF contractor did what I would consider to be a top level job. And I should know. I have been in the spray foam business starting on 9 years. The quality of the spray foam contractor is very important. Too many people want to get into the spray foam business and think it only takes a used rig from Ebay and "training" from a few TH-cam videos. I suggest only hiring contractors who have completed SPFA training.
Or add a radiant barrier. Maybe you hold on the conditioned attic till you are already doing a large remodel in the future to bring down the overall costs. Best, Matt
that's awesome that there is only a few degree difference between the room and the attic. I live in the Florida panhandle, and good luck going in the attic if you live in an older house in the summer.
Johnintoit - thx! Yes, the 30% tax credit weighed in as crucial on our decision. However we have run into a snag with drilling! Ugh. The geothermal unit is in attic and venting is done, but a/c peeps having a hard time scheduling a driller who has a buggy rig small enough to fit in backyard area where loops will go. I am not sure we will EVER have a/c. Unit has been installed over a month now with no ground loops in sight! Tip for you... Do loops before slab is poured so you won't have my problem! Let's both hope the geothermal is a most excellent choice! :) good luck with yours and thanks for reply!
Yes there is a concern about leaving foam unprotected in the attic. There is a second spray component that should be added over the foam. Or recently you can order a foam rated for uncovered attic installation without the extra protection, but you are not allowed to store anything in the attic. Demilec APX is one such "safe" foam. I took a piece of it and tried to ignite it with a propane torch. It just charred. Out-gassing after install and during a fire situation is also considered.
Daniel, In the hot/humid Southern US you generally want to use Open Cell above grade. Closed cell is the "Lexus" product but isn't necessary and could be harmful if not detailed correctly. Does this help? Matt
When you insulate the roof deck you then have to include the attic volume and surface area in the Heat Load Analysis. This will add somewhat to the required HVAC equipment.
That's hilarious! Yes indeed I'd like to build one myself! I find it crazy that we are still building houses in Texas the same as we were in the 50's,60's,70's with duct work in a Super Hot attic and traditional insulation laid over the drywall. Texas attics are disgusting and terribly in-efficient. Appreciate you commenting. Best, Matt
Pricing if they are not in your area, I know that Matt is going to tell you to look in your area between all the different Spray Foam Insulation Companies to find what you like best, and also for the best price. I would think that pricing is pretty stable, seeing as Spray Foam is not new, been around in the US since the 90's, I remember the first time it was used on This Old House, it was the Poly Urethane Spray Insulation. Like I said call around or look online at your local companies.
I can help with a couple of your questions @ricksite and @JoeLarge. Yes they do trim the insulation after it is sprayed, also as he mentioned in the video open cell was used. Open cell is the cheaper than closed cell spray insulation. I would go online and look for local companies in your area and see the best price you can get. Also many different types of spray foam insulation, so cost will vary between the different choices. I know this from general research, no one can give you the exact
Hey Matt, there is a lot of info on spray foam all over the internet . But I would like to hear your thoughts on spraying from the outside in. I have T-111 on my place as the sheathing / siding. I want to pull it remove the old fiberglass and spray the cavity (2x4) with closed cell, reinstall the t-111, followed by tyvek drain wrap, 1 inch rigid foam then new (concrete or vinyl) siding. Thanks for all the advice you give in your series of videos. The only negative is that I now see all the problems with my house! Good stuff.
Couple questions here. First, what climate zone are you in? You need to be careful with closed cell foam then other layers outside of that because the closed cell is a total vapor and water barrier. If you have an air or water leak you can have rot/mold issues if there is anything in the assembly that's not perfect. I would consult the "Builders Guide" book by Dr Joe Lstiburek for advice. He's published one for each of the climate zones in the US and strategies differ depending on your location. You can buy it on their website building science dot com Best, Matt
I've seen Cement Foam used--seems like terrific stuff--It's bug, critter, mold, and fire-proof, as well as very non-toxic---we NEED all those qualities! Is it an open-cell or closed cell? We're in the Pacific NW...Where can one get it, or, who installs it? Can it easily be retro-fitted in older homes? How does it's insulative quality stack-up to other insulation foams? Thank you for your good work getting information shared!
Remodeling brick faced house with 2 x 4 wall in northeast Connecticut. A little cunfused on open or closed in wall and attic, could you explain pros and cons and you mentioned if the wall gets wet the closed will not let it dry but the open will.
When the foam guy came to my house to use closed cell foam, he said they do not insert below or above or next to any door and window! Yet in this video, I see that in fact it is done! Should I call them back? It cost me $5500 for a little over 1000 sq ft.
Concerning budget, you have to consider that your heat and ac bills will go down by 25-50% so it has a payback in a few years. Often the HVAC units are downsized by an equal amount, saving a little. Plus excellent conventional insulation costs money to install properly, low bidders just don't do a good job. The spray foam materials are the largest wholesale cost component.
Matt, would you cover the main reasons why these spray foams may fail or become dangerous if certain procedures are not followed during install. I would like to kind of know what to look out for. Thank you in advance for your help.
I have a friend who is having a house built. I told her to ask about spray foam insulation. It didn't fit into the budget. Do you think the price will ever come down (similar to other insulation methods)? Does the high cost come from the materials, labor or both?
Matt, I just received a proposal to retrofit/convert my attic to unvented. At a minimum, the work involved applying the foam to the underside of the roof and removal of my old blown-in insulation. Their price was about what I can buy a complete new HVAC system for. If it saves me 25% of my heating/cooling costs, the payback would be about 45 years!! I can hardly imagine how even a super-competitive bid can make sense economically. I think payback MUST be no more than 10 years. Your thoughts?
Sometimes you suggest closed cell foam, other times it is open cell foam. I know the difference between closed and open cells but not when to use. I thought closed cell was always superior. Please explain.
worlds best pretty much. Make sure you are done in the walls before you retrofoam. I'm sure you can do what you want after it's been done but it's gonna be annoying for sure
hey matt im building a house in houston. what about fresh air supply into the house, will foam create moisture due to the ac? would i just need a damper and problem fixed?
Matt - what's your thoughts on cellulose vs spray foam. I leave south of Houston, Tx (zone 2) and more then Austin usually, it's very humid along the coast. Thanks!
how would this compare as far as fire safety compared to using something like a mineral wool insulation? I'm concerned about fires like what happened in London with foam insulation fires.
all spray foam has a degree of fire retardant but if its a major concern you can have the fire proof foam sprayed in ... its a red/ orange color.. bit more expensive tho.
I really like your videos because they are informative and concise. Is there any concern about leaving the foam unprotected in the attic, i.e., in the event of a fire?
Did you also put exterior foam on this house? I'm curious if you use radiant barrier on your houses with conditioned attics or is it not worth the additional benefit?
Dax, This house did not get exterior rigid foam. We used Advanced Framing on 24" centers and insulated headers to minimize the thermal bridges. Rigid foam would have been better but we couldn't work it in this house's budget. In order for a radiant barrier to work it must have an air gap in front of it, so with the foamed attic we didn't use radiant barrier decking. Instead we are using a Galvalume (silver) metal roof that will provide a radiant benefit. Best, Matt
I would be careful about saying that it is more efficient to move the insulation from the attic floor to the roof. You will have less heat transfer from the ducting to the surrounding air. However, if you don't have insulation separating your attic space and your living space then you will be increasing the volume of air that your HVAC system has to condition (living space + attic). That will increase energy costs. It would probably depend on how large your attic space is to determine if it is worth adding the attic to the conditioned space. Though adding insulation directly to the ducts is probably your most efficient solution. Better to apply insulation directly to the problem area than to insulate its surroundings.
I thought about this issue also. I thought maybe the idea was to not cool or heat the attic so the attic space doesn't use energy for heating or cooling. but it is highly insulated so the temperature is much closer to in door temperatures than out door temperatures. Of course, just based on the geometry you need a lot more insulation to cover the underside of the roof than you do to cover the floor of the attic. Air exchanges on a tight house might be another issue..
Hi Matt, thanks so much for sharing wonderful video. We have recently purchased 85 years old home in Philadelphia area. Your video helped us a lot doing lots of home improvement projects so far inculding replacing windows and installing new central A/C. Now it is time to consider insulating the house. Before installing AHU and ductwork in attic, we completly removed old insulation and cleaned out the attic which looked horrible before. Q1) Here in eastcoast, cooling season is short, only a few months are hot. In this case, should I consider foam insulation under the roof line? or would loose fill fiberglass on the floor be enough? FYI, our attic is not ventilated any more since hvac contractor deactivated whole house attic fan and there is no soffit. We also have ventilated crawl space with dirt floor under the kitchen and dining room. There is no water or mold issue (according to home inspection report) there but i experienced musty odor smearing through the floor in summer time(decomposting smell-like, I am the only person who smells this and my husband does not) only and very cold floor in my kitchen and dining room in winter. There is very old Batt insuation under the floor. Q2) I am planning to remove old batt insulation under floor --> apply anti-microbial spray --> add new insulation --> install vapor barrier onto the floor. Does this make sense to you, ecomonically speaking? Q3) Should I close the vent or leave the vent open? Q4) Where should I insulate if I want to choose between wall and under floor? since closed cell foam is expensive, I may have to choose one area. Thanks so much in advance!!
Wow, lots of good questions here. First, I want to point out that my videos are from the perspective of a hot/humid climate. Your house is in a VERY different climate zone. I would recommend buying "The Builders Guide to Cold Climates" by Dr Joe Lstiburek available on buildingscience dot com's website. Encapsulating your crawlspace with Cleanspace or another vapor barrier product should eliminate that smell and you could close your vents at the same time. Lastly, if you have to choose I'd insulate your floor/crawlspace correctly to make that a conditioned crawl space then spend the money on walls. I'll bet your floor is VERY cold in the winter time. Best, Matt
can you use fiberglass batts in your raffters to get a conditioned attic aswell? i know it wont be as great as foam but if it will still work to help my AC run better im all for it.
You can, but you must seal your venting (eaves, and ridge depending on style) and Batts are ok, but look into BIBS especially since it is where the greatest mount of heat is transferred.
What is the latest about toxic fumes from these foams. I'm thinking of a sill plate use in basement where it would be exposed to occasional visits to basement.
The only concern is fire where the foam is uncovered. Code calls for a covering of several options to ensure that burning foam won't smoke the house before you have time to escape. Other than that exposed foam is harmless. Matt
Forgot they just cut the Insulation after it has expanded, flush with the wall so you can hang your dry wall, cement board,etc. Just type in cutting spray foam on here, you will see a lot of videos showing how it is done.
very interesting discussions folks, their really is not a better insulation then foam ... Open or closed cell, However! the application of the product is the key to insure the fire package works and the 1:1 chemistry is applied by professionals ONLY. The industry (and more importantly their customers) suffer the consequences of carless uncertified contractors using Undersize or defective equipment.
Matt, I have learned a lot watching your vids. I'm currently working on building a new home myself and wanted to ask you about spray foam. I want to use closed cell in roof and walls but was told by my spray foam contractor that using closed cell won’t work for my walls. His reason was that when we spray foam the inside of the interior walls. And then use a house wrap on the outside it will trap moisture between the house wrap and closed cell foam and cause the OSB board to rot. Your thoughts?
Closed Cell will work great in your climate. I would recommend a low perm Housewrap like DuPont Commercial Tyvek or even Carlisle CCW 705. Keep in mind that closed cell foam is pricey, and Open cell will do many (not all) of the benefits at less than 1/2 the cost. Best, Matt
I was taught to use closed cell foam because it will not absorb and hold water as well as being impermeable. Yet, you specify open cell foam. What gives?
John, There is a lot to talk about on this topic. Yes Rigid Foam doesn't absorb water, is vapor impermeable, and adds structural rigidity to the assembly. However, it's a lot more expensive and you need to be certain that your wood framing won't get wet as it'll never dry through the closed cell foam. In general I use open cell foam here in the hot/humid south because it's a lot less expensive, it provides a good air block (if it's 3.5" thick) and it's vapor open so your assembly can dry to the interior. Matt
Matt Risinger Hey Matt, I was curious, whenever you discover a new method that supersedes one of your old methods, do you still support the old method? For example, a few years ago one of your videos talks about using closed cell foam with a cellulose chaser. Is closed cell not recommended anymore here in the humid south? Also I like the 500 year "perfect wall" system, I wonder how long it will take for more builders to embrace that concept.
+Vince Stagbaugh I will take on that one, just passing by, Vince. (I am an HVAC engineer.) Even if the room/space where the ducts are located is "conditioned", the humidity may still be above the dew point temperature of the duct work. This effect is amplified after, say, a weekend away in the cooling season. Turn on the AC and it will take a few hours to recover space conditions. In the meantime though, the AC process will cool the air below the space dew point and cause condensation. Even without an unoccupied period and recovery, AC systems tend to run colder than space dew point, especially when in dehumidification mode. Hope this helps.
Matt - do you have a preference on spray foam brand? We are building a new home. I have been researching demilec apx and icynene and have no clear winner. I am installing a geothermal system and it was costly. I need to get the biggest bang for my buck on spray foam. Both tout their products as "best". There is about a $1500 cost difference between the two. Your advice is much appreciated!
Kim, Glad to hear you are doing a high performance build! I'm not brand specific on SPF. I would choose the best contractor who will do a good job and if you can save $1500 I would do it. Watch my video on how to "pre-foam" for some tips on what you can do before they arrive. th-cam.com/video/QRzu3cg-9eE/w-d-xo.html Best, Matt
First off great videos Mat, keep them coming, Kim I too am building a new home (next year) and I'm also going geothermal, I live in Ohio and we have a 30% tax break for labor/material up until the end of 2016 and that's a huge break, not sure if your aware of that or not so I thought I would point it out, good luck.
They spray work looks ok at best. What do you spray expert level sprayers/ crew lead? or a Production manager I may be looking for work in that area. Let me know Thanks
Matt just watched your video I am looking for ideas on insulating metal buildings....I am in process of selling out to move to montana. I am looking at purchasing a 24X36 metal garage to turn into a house... any suggestions on the best way to insulate for the cold northwestern montana winters?
+john nelson John, it cannot be done, metal buildings converted into homes is a no-go-area. By metal garage I take it to mean metal sheet steel walls, roof, floor, steel beam/s supports and framework. Steel is an always open door- for heat to escape, it would be like living inside a river, under a waterfall, like always having the kettle on and boiling heat away. think again.
SuttonWoods no only a metal exterior....wood floor, with wood walls,most likely dry wall ceilings. The only metal would be outdoor walls and the roof....still a no go?....it would have wood framed walls as well....none of the support s would be metal...basically a pole barn converted into a house.
+john nelson John, think condensation and and cold spots. I could get around this but there would be no advantage whatsoever in steel cladding, and health wise I'm saying keep well away. Think big, dream a little, and do something you and you're family can be proud off, Houses and people need to breathe, bones and human skeletons have to be kept healthy, I'm saying think asthma, think bad winters, Montana is an iceberg in winter, best regards.
+john nelson / All ideas are good even bad ones, bad ideas prove or disprove the benefits and disadvantages off more credible ideas. So lets stick with you're idea and you start a business called METALLICA INC, and you start selling corrugate steel sheets to farmers for reroofing barns, steel posts and livestock pens,, corrugated roofing tiles, steel doors, corn silos, metal gates and door protection frames, and new warehouse business units or SELF ERECT KITS, A John Nelson METALLICA Roof is forever, No deposits - We will invoice you on delivery, can you see what I am getting at? Ideas are a stream of conciousness about the real word, O.K you're going to get rich but don't let that put you off. SW ENGLAND UK.
I like foam, however, I have seen that if its not done properly it can put off fumes and make the house unlivible and even dangerous. Removing it is expensive in that case.
Anthony, you are quite correct. The installation is key. If your insulation contractor is installing closed cell (culprit for fumes) they need to make sure they are only doing 1.5" to 2" layers at a time. Usually a good rule of thumb, do a layer on the exterior wall of a room and once that wall is complete, start over again. The first layer will be "cured" enough for the second layer and such. If foam makes one nervous, a great value is the Blown in Blanket System (BIBS) that even Matt talks about. Proper vapor barriers and sealing will be needed, but a great system still.
Your information on Closed Cell vs. Open Cell is nor correct. Open Cell: C.C. Foam All Climate Zones,Air Barrier, Adds structural rigidity, Moisture Barrier, Resists water, Type II vapor retarder, 4-Barrier Thermal , Air, Moisture, vapor, Resistant to flood damage, Exterior uses, Roofing, Insurance Companies love this stuff. O.C. Foam is not the same.
Closed cell is much higher in R-value but it's 2-3x the cost. I highly recommend it if you need it for additional structural properties (Hurricane resistance for example) but I use it mainly for below grade applications. No doubt it's the top-of-the-line foam, but it's hard to budget for frankly. Thanks for being a faithful subscriber! Best, Matt
Richard is spot on here. You need to read the ICCES report from the manufacturer of the foam you spray to determine what/if you need an ignition barrier. A few foams meet the spec without adding an ignition barrier, so require it. An easy ignition barrier is an intumescent paint. That's my typical final step in attics when necessary. Matt
Joe, They trim the foam flush to the studs. This is open cell foam so it's pretty soft/easy to trim. It's hard to say on cost for a 2000sf house but it's likely $5-8k with the specs you are seeing in this video. Costs vary widely depending on the region and availability of subs who are foaming daily. The busier the foam crew the better the installed costs I've found. Best, Matt
Yes I've seen that happen. It seems to occur most when the foam can't stick on three sides of a stud bay. For instance, if you were spraying against a cardboard or plastic vent inside a rafter bay where it only adheres to the 2x rafter on two sides but not on the back of the OSB/Plywood. It can also happen if conditions aren't right (mix, temp, etc). With a trained crew this is less a concern. Best, Matt
Thanks buddy! Always appreciate a kind word. Matt
Conditioned attic space...outside temp 100, 74 in room and 76 in attic?!!!! I'm drooling at the thought. Damn it Matt, your vids always make me want to have a new house built!
Gary,
It's hard to estimate payback but it could be very likely that it's a 10+ year payback. Retrofits are tough and expensive. The payback is much sooner if you are looking at new construction. Your money might be better spent on an Energy Audit by a BPI certified rater. Hire an independent auditor that doesn't work for an insulation company. They can identify "low hanging fruit" to upgrade. It may be better in terms of payback to upgrade your HVAC, tighten your leaky ducts, or...
Spray foam is definitely more expensive than traditional insulation but it's well worth the cost upgrade. With the air sealing benefits, the increased effective R-value, and the ability to insulate areas that can't be insulated effectively with fiberglass I think foam is tough to beat. Costs have come down in Austin because it's being used a lot so subs are busy. The materials are expensive, the machinery needed to spray is expensive, and the upkeep on the machines is expensive. Best, MR
Good luck in your searches! Matt is always so helpful, keep up the Great work with the videos about Building Science!!! Yes I LOVE the term Building Science, because that's what it is. Have a Great Weekend!
Great video blog. And even better job completed by the spray foam contractor. The SPF contractor did what I would consider to be a top level job. And I should know. I have been in the spray foam business starting on 9 years. The quality of the spray foam contractor is very important. Too many people want to get into the spray foam business and think it only takes a used rig from Ebay and "training" from a few TH-cam videos. I suggest only hiring contractors who have completed SPFA training.
Or add a radiant barrier. Maybe you hold on the conditioned attic till you are already doing a large remodel in the future to bring down the overall costs. Best, Matt
that's awesome that there is only a few degree difference between the room and the attic. I live in the Florida panhandle, and good luck going in the attic if you live in an older house in the summer.
@BigDell500, Well said! I need to sub-contract my answers to you, apparently someone has trained you well! Appreciate you commenting. Matt
Johnintoit - thx! Yes, the 30% tax credit weighed in as crucial on our decision. However we have run into a snag with drilling! Ugh. The geothermal unit is in attic and venting is done, but a/c peeps having a hard time scheduling a driller who has a buggy rig small enough to fit in backyard area where loops will go. I am not sure we will EVER have a/c. Unit has been installed over a month now with no ground loops in sight! Tip for you... Do loops before slab is poured so you won't have my problem! Let's both hope the geothermal is a most excellent choice! :) good luck with yours and thanks for reply!
Yes there is a concern about leaving foam unprotected in the attic. There is a second spray component that should be added over the foam. Or recently you can order a foam rated for uncovered attic installation without the extra protection, but you are not allowed to store anything in the attic. Demilec APX is one such "safe" foam. I took a piece of it and tried to ignite it with a propane torch. It just charred. Out-gassing after install and during a fire situation is also considered.
Love your TH-cam channel. Professional presentation.
+Simon Cassar thanks!
Daniel, In the hot/humid Southern US you generally want to use Open Cell above grade. Closed cell is the "Lexus" product but isn't necessary and could be harmful if not detailed correctly. Does this help? Matt
When you insulate the roof deck you then have to include the attic volume and surface area in the Heat Load Analysis. This will add somewhat to the required HVAC equipment.
That's hilarious! Yes indeed I'd like to build one myself! I find it crazy that we are still building houses in Texas the same as we were in the 50's,60's,70's with duct work in a Super Hot attic and traditional insulation laid over the drywall. Texas attics are disgusting and terribly in-efficient. Appreciate you commenting. Best, Matt
Pricing if they are not in your area, I know that Matt is going to tell you to look in your area between all the different Spray Foam Insulation Companies to find what you like best, and also for the best price. I would think that pricing is pretty stable, seeing as Spray Foam is not new, been around in the US since the 90's, I remember the first time it was used on This Old House, it was the Poly Urethane Spray Insulation. Like I said call around or look online at your local companies.
I can help with a couple of your questions @ricksite and @JoeLarge. Yes they do trim the insulation after it is sprayed, also as he mentioned in the video open cell was used. Open cell is the cheaper than closed cell spray insulation. I would go online and look for local companies in your area and see the best price you can get. Also many different types of spray foam insulation, so cost will vary between the different choices. I know this from general research, no one can give you the exact
The wall, roof and other building assemblies have determined R-values, so they get included for total R-values, right?
Hey Matt, there is a lot of info on spray foam all over the internet . But I would like to hear your thoughts on spraying from the outside in. I have T-111 on my place as the sheathing / siding. I want to pull it remove the old fiberglass and spray the cavity (2x4) with closed cell, reinstall the t-111, followed by tyvek drain wrap, 1 inch rigid foam then new (concrete or vinyl) siding. Thanks for all the advice you give in your series of videos. The only negative is that I now see all the problems with my house! Good stuff.
Couple questions here. First, what climate zone are you in? You need to be careful with closed cell foam then other layers outside of that because the closed cell is a total vapor and water barrier. If you have an air or water leak you can have rot/mold issues if there is anything in the assembly that's not perfect. I would consult the "Builders Guide" book by Dr Joe Lstiburek for advice. He's published one for each of the climate zones in the US and strategies differ depending on your location. You can buy it on their website building science dot com Best, Matt
I noticed you added additional blocking. So whats point using 24" centers. Also all that foam can be a real fire hazard in a lightning strike.
I have heard that spray foam can shrink over time (years). Have you heard anything about foam shrinking? (leaving gaps)
I've seen Cement Foam used--seems like terrific stuff--It's bug, critter, mold, and fire-proof, as well as very non-toxic---we NEED all those qualities!
Is it an open-cell or closed cell?
We're in the Pacific NW...Where can one get it, or, who installs it?
Can it easily be retro-fitted in older homes?
How does it's insulative quality stack-up to other insulation foams?
Thank you for your good work getting information shared!
Remodeling brick faced house with 2 x 4 wall in northeast Connecticut. A little cunfused on open or closed in wall and attic, could you explain pros and cons and you mentioned if the wall gets wet the closed will not let it dry but the open will.
When the foam guy came to my house to use closed cell foam, he said they do not insert below or above or next to any door and window! Yet in this video, I see that in fact it is done! Should I call them back? It cost me $5500 for a little over 1000 sq ft.
Concerning budget, you have to consider that your heat and ac bills will go down by 25-50% so it has a payback in a few years. Often the HVAC units are downsized by an equal amount, saving a little. Plus excellent conventional insulation costs money to install properly, low bidders just don't do a good job. The spray foam materials are the largest wholesale cost component.
Matt, would you cover the main reasons why these spray foams may fail or become dangerous if certain procedures are not followed during install. I would like to kind of know what to look out for. Thank you in advance for your help.
I have a friend who is having a house built. I told her to ask about spray foam insulation. It didn't fit into the budget. Do you think the price will ever come down (similar to other insulation methods)? Does the high cost come from the materials, labor or both?
Matt, I just received a proposal to retrofit/convert my attic to unvented. At a minimum, the work involved applying the foam to the underside of the roof and removal of my old blown-in insulation. Their price was about what I can buy a complete new HVAC system for. If it saves me 25% of my heating/cooling costs, the payback would be about 45 years!! I can hardly imagine how even a super-competitive bid can make sense economically. I think payback MUST be no more than 10 years. Your thoughts?
So do they trim foam in wall cavity how do they do it? For 2000 sf home how much for spray foam?
Sometimes you suggest closed cell foam, other times it is open cell foam. I know the difference between closed and open cells but not when to use. I thought closed cell was always superior. Please explain.
If attic insulation is now required at an R38 value, why is foam applied to roof decking not also required for this?
Doesnt spray foam cause troubles adding new outlets and plumbing later on down the line in the houses life
worlds best pretty much. Make sure you are done in the walls before you retrofoam. I'm sure you can do what you want after it's been done but it's gonna be annoying for sure
Yes.
hey matt im building a house in houston. what about fresh air supply into the house, will foam create moisture due to the ac? would i just need a damper and problem fixed?
Do you agree with the technique of spraying all ductwork joints and connections with foam ?
Closed cell foam provides structural support for additional strength for hurricanes? Where can I find information about that?
Why not closed cell foam in the walls? Doesn't closed cell have a higher R value? Thanks
Matt - what's your thoughts on cellulose vs spray foam. I leave south of Houston, Tx (zone 2) and more then Austin usually, it's very humid along the coast. Thanks!
how would this compare as far as fire safety compared to using something like a mineral wool insulation? I'm concerned about fires like what happened in London with foam insulation fires.
all spray foam has a degree of fire retardant but if its a major concern you can have the fire proof foam sprayed in ... its a red/ orange color.. bit more expensive tho.
I really like your videos because they are informative and concise.
Is there any concern about leaving the foam unprotected in the attic, i.e., in the event of a fire?
Did you also put exterior foam on this house? I'm curious if you use radiant barrier on your houses with conditioned attics or is it not worth the additional benefit?
Dax, This house did not get exterior rigid foam. We used Advanced Framing on 24" centers and insulated headers to minimize the thermal bridges. Rigid foam would have been better but we couldn't work it in this house's budget. In order for a radiant barrier to work it must have an air gap in front of it, so with the foamed attic we didn't use radiant barrier decking. Instead we are using a Galvalume (silver) metal roof that will provide a radiant benefit. Best, Matt
I would be careful about saying that it is more efficient to move the insulation from the attic floor to the roof. You will have less heat transfer from the ducting to the surrounding air. However, if you don't have insulation separating your attic space and your living space then you will be increasing the volume of air that your HVAC system has to condition (living space + attic). That will increase energy costs. It would probably depend on how large your attic space is to determine if it is worth adding the attic to the conditioned space. Though adding insulation directly to the ducts is probably your most efficient solution. Better to apply insulation directly to the problem area than to insulate its surroundings.
I thought about this issue also. I thought maybe the idea was to not cool or heat the attic so the attic space doesn't use energy for heating or cooling. but it is highly insulated so the temperature is much closer to in door temperatures than out door temperatures. Of course, just based on the geometry you need a lot more insulation to cover the underside of the roof than you do to cover the floor of the attic. Air exchanges on a tight house might be another issue..
Hi Matt, thanks so much for sharing wonderful video. We have recently purchased 85 years old home in Philadelphia area. Your video helped us a lot doing lots of home improvement projects so far inculding replacing windows and installing new central A/C. Now it is time to consider insulating the house. Before installing AHU and ductwork in attic, we completly removed old insulation and cleaned out the attic which looked horrible before.
Q1) Here in eastcoast, cooling season is short, only a few months are hot. In this case, should I consider foam insulation under the roof line? or would loose fill fiberglass on the floor be enough? FYI, our attic is not ventilated any more since hvac contractor deactivated whole house attic fan and there is no soffit.
We also have ventilated crawl space with dirt floor under the kitchen and dining room. There is no water or mold issue (according to home inspection report) there but i experienced musty odor smearing through the floor in summer time(decomposting smell-like, I am the only person who smells this and my husband does not) only and very cold floor in my kitchen and dining room in winter. There is very old Batt insuation under the floor.
Q2) I am planning to remove old batt insulation under floor --> apply anti-microbial spray --> add new insulation --> install vapor barrier onto the floor. Does this make sense to you, ecomonically speaking?
Q3) Should I close the vent or leave the vent open?
Q4) Where should I insulate if I want to choose between wall and under floor? since closed cell foam is expensive, I may have to choose one area.
Thanks so much in advance!!
Wow, lots of good questions here. First, I want to point out that my videos are from the perspective of a hot/humid climate. Your house is in a VERY different climate zone. I would recommend buying "The Builders Guide to Cold Climates" by Dr Joe Lstiburek available on buildingscience dot com's website. Encapsulating your crawlspace with Cleanspace or another vapor barrier product should eliminate that smell and you could close your vents at the same time. Lastly, if you have to choose I'd insulate your floor/crawlspace correctly to make that a conditioned crawl space then spend the money on walls. I'll bet your floor is VERY cold in the winter time. Best, Matt
can you use fiberglass batts in your raffters to get a conditioned attic aswell? i know it wont be as great as foam but if it will still work to help my AC run better im all for it.
You can, but you must seal your venting (eaves, and ridge depending on style) and Batts are ok, but look into BIBS especially since it is where the greatest mount of heat is transferred.
What is the latest about toxic fumes from these foams. I'm thinking of a sill plate use in basement where it would be exposed to occasional visits to basement.
The only concern is fire where the foam is uncovered. Code calls for a covering of several options to ensure that burning foam won't smoke the house before you have time to escape. Other than that exposed foam is harmless. Matt
Forgot they just cut the Insulation after it has expanded, flush with the wall so you can hang your dry wall, cement board,etc. Just type in cutting spray foam on here, you will see a lot of videos showing how it is done.
What is popular flooring for slab on grade if I want engineered wood flooring? I have been told Chinese stuff delaminates.
very interesting discussions folks, their really is not a better insulation then foam ... Open or closed cell, However! the application of the product is the key to insure the fire package works and the 1:1 chemistry is applied by professionals ONLY. The industry (and more importantly their customers) suffer the consequences of carless uncertified contractors using Undersize or defective equipment.
Matt, I have learned a lot watching your vids. I'm currently working on building a new home myself and wanted to ask you about spray foam. I want to use closed cell in roof and walls but was told by my spray foam contractor that using closed cell won’t work for my walls. His reason was that when we spray foam the inside of the interior walls. And then use a house wrap on the outside it will trap moisture between the house wrap and closed cell foam and cause the OSB board to rot. Your thoughts?
What part of the US are you in? I would generally say your insulator is wrong. But there can be exceptions. Was that ambiguous enough?
Matt Risinger Central Fl.
Closed Cell will work great in your climate. I would recommend a low perm Housewrap like DuPont Commercial Tyvek or even Carlisle CCW 705. Keep in mind that closed cell foam is pricey, and Open cell will do many (not all) of the benefits at less than 1/2 the cost. Best, Matt
good information, thanks
I was taught to use closed cell foam because it will not absorb and hold water as well as being impermeable. Yet, you specify open cell foam. What gives?
John, There is a lot to talk about on this topic. Yes Rigid Foam doesn't absorb water, is vapor impermeable, and adds structural rigidity to the assembly. However, it's a lot more expensive and you need to be certain that your wood framing won't get wet as it'll never dry through the closed cell foam. In general I use open cell foam here in the hot/humid south because it's a lot less expensive, it provides a good air block (if it's 3.5" thick) and it's vapor open so your assembly can dry to the interior. Matt
Matt Risinger Hey Matt, I was curious, whenever you discover a new method that supersedes one of your old methods, do you still support the old method? For example, a few years ago one of your videos talks about using closed cell foam with a cellulose chaser. Is closed cell not recommended anymore here in the humid south? Also I like the 500 year "perfect wall" system, I wonder how long it will take for more builders to embrace that concept.
What do you think about icf?
IF LITTLE FIRE, U CAN FIND ONLY SMOKE FROM THIS HOUSE
Why do you use insulated air ducts if your attic is conditioned?
+Vince Stagbaugh
I will take on that one, just passing by, Vince. (I am an HVAC engineer.)
Even if the room/space where the ducts are located is "conditioned", the humidity may still be above the dew point temperature of the duct work. This effect is amplified after, say, a weekend away in the cooling season. Turn on the AC and it will take a few hours to recover space conditions. In the meantime though, the AC process will cool the air below the space dew point and cause condensation.
Even without an unoccupied period and recovery, AC systems tend to run colder than space dew point, especially when in dehumidification mode.
Hope this helps.
Matt - do you have a preference on spray foam brand? We are building a new home. I have been researching demilec apx and icynene and have no clear winner. I am installing a geothermal system and it was costly. I need to get the biggest bang for my buck on spray foam. Both tout their products as "best". There is about a $1500 cost difference between the two. Your advice is much appreciated!
Kim, Glad to hear you are doing a high performance build! I'm not brand specific on SPF. I would choose the best contractor who will do a good job and if you can save $1500 I would do it. Watch my video on how to "pre-foam" for some tips on what you can do before they arrive. th-cam.com/video/QRzu3cg-9eE/w-d-xo.html
Best, Matt
First off great videos Mat, keep them coming, Kim I too am building a new home (next year) and I'm also going geothermal, I live in Ohio and we have a 30% tax break for labor/material up until the end of 2016 and that's a huge break, not sure if your aware of that or not so I thought I would point it out, good luck.
Johnintoit Let me know how your system turns out! I think GeoThermal is a good choice for Ohio. The tax credit certainly helps! Best, Matt
They spray work looks ok at best. What do you spray expert level sprayers/ crew lead? or a Production manager I may be looking for work in that area. Let me know Thanks
Matt just watched your video I am looking for ideas on insulating metal buildings....I am in process of selling out to move to montana. I am looking at purchasing a 24X36 metal garage to turn into a house... any suggestions on the best way to insulate for the cold northwestern montana winters?
+john nelson John, it cannot be done, metal buildings converted into homes is a no-go-area. By metal garage I take it to mean metal sheet steel walls, roof, floor, steel beam/s supports and framework. Steel is an always open door- for heat to escape, it would be like living inside a river, under a waterfall, like always having the kettle on and boiling heat away. think again.
SuttonWoods no only a metal exterior....wood floor, with wood walls,most likely dry wall ceilings. The only metal would be outdoor walls and the roof....still a no go?....it would have wood framed walls as well....none of the support s would be metal...basically a pole barn converted into a house.
+john nelson John, think condensation and and cold spots. I could get around this but there would be no advantage whatsoever in steel cladding, and health wise I'm saying keep well away. Think big, dream a little, and do something you and you're family can be proud off, Houses and people need to breathe, bones and human skeletons have to be kept healthy, I'm saying think asthma, think bad winters, Montana is an iceberg in winter, best regards.
Just when I thought I had a good idea
+john nelson / All ideas are good even bad ones, bad ideas prove or disprove the benefits and disadvantages off more credible ideas. So lets stick with you're idea and you start a business called METALLICA INC, and you start selling corrugate steel sheets to farmers for reroofing barns, steel posts and livestock pens,, corrugated roofing tiles, steel doors, corn silos, metal gates and door protection frames, and new warehouse business units or SELF ERECT KITS, A John Nelson METALLICA Roof is forever, No deposits - We will invoice you on delivery, can you see what I am getting at? Ideas are a stream of conciousness about the real word, O.K you're going to get rich but don't let that put you off. SW ENGLAND UK.
I like foam, however, I have seen that if its not done properly it can put off fumes and make the house unlivible and even dangerous. Removing it is expensive in that case.
Anthony, you are quite correct. The installation is key. If your insulation contractor is installing closed cell (culprit for fumes) they need to make sure they are only doing 1.5" to 2" layers at a time. Usually a good rule of thumb, do a layer on the exterior wall of a room and once that wall is complete, start over again. The first layer will be "cured" enough for the second layer and such. If foam makes one nervous, a great value is the Blown in Blanket System (BIBS) that even Matt talks about. Proper vapor barriers and sealing will be needed, but a great system still.
I'm pretty sure he meant to say Closed Cell spray foam.
R-25? in the roof and R-19 in the wall? Interesting design...
Matt Risinger thou art a God.
Mmmm spray foam = solid fuel for a fire. Cellulose or mineral wool for a real home
Thx.
24 on center on exterior walls but 16 on the interior? Seems to me if you were gunna Change your layout it would be the other way around lol.
I wondered about that also. If flexing of drywall was the issue you could use 5/8 inch dry wall.
Also, open cell foam does not add any structural rigidity.
The narrator keeps calling the foam OPEN cell, you need CLOSED CELL 2lb. foam, it meets all moisture, vapor, air barrier codes.
still eating the sweater tsk tsk people will never learn
Your information on Closed Cell vs. Open Cell is nor correct. Open Cell:
C.C. Foam All Climate Zones,Air Barrier, Adds structural rigidity, Moisture Barrier, Resists water, Type II vapor retarder, 4-Barrier Thermal , Air, Moisture, vapor, Resistant to flood damage, Exterior uses, Roofing, Insurance Companies love this stuff.
O.C. Foam is not the same.
Nice try.