I use to be an applicator as I had my own employees and equipment when I was a new home builder to apply the closed cell foam. One thing you MUST know if you have a conscience and or have loved ones benefiting from the great insulation is that in the case of a house fire, even though the foam has or should have fire retardants , in the presence of flame the foam puts off cyanide gas. CYANIDE POISON gas. One breath of this stuff and you are incapacitated unlike regular smoky wood buildings. If you doubt me the chemical name for the cured foam is Poly-ISO-Cyanurate. Do you see the cyanide component ? That is one reason why all building codes require fire barriers covering all foam in areas that are inhabited. My family and relatives have saved many thousands of dollars in utility costs over the twenty years since I built their homes and they enjoy stupendous savings in heating and cooling as I went a little overboard in thickness since it was my own house and I was the wholesale applicator for myself. ie 2x6 exterior walls filled and 2x10s roof members filled in addition to R-25 batts above the ceiling and R 8 batts between floors as sound insulation. So be very very careful to not do stupid things that the insurance companies say cause 80 percent of all fires like Storing gas in garages with water heaters and burning candles and using cheap chimneys. BTW, the entire marine and boating industry uses closed cell poly-iso-cyanurate ( poly-urethane ) foams as floatation in boats and floats because it will NOT soak up water. Further there are off-gases immediately after spraying while curing that is VERY TOXIC so make absolutely sure you have large fans blowing for ventilation and you must vacate the house for at least 24 hours after spraying and be sure to provide plenty of ventilation. I had an applicator that inhaled too much of the off-gas and he had to go to hospital intensive care for 2 days because of suffering pulmonary edema. ( swelling around lungs and heart that prevents breathing and intake of oxygen from the air.) This seems like a lot of negative but this foam is absolutely magic when it comes to saving money... Your dwelling can become futuristic thermal spaceships if properly taken advantage of. I just wanted to fill in with some important missed but critical details.
I really really appreciate your comment. I'm looking to used ccSPF as an air sealant / vapour barrier in my attic before adding blown in cellulose insulation...I've also seen horrific videos of families having to move out of their homes because of off gassing....I'm really reluctant to use it as an air sealer but it's what everyone is recommending.
Hey Scott, I am planning on using the foam for some outdoor projects, that would be the foam in bulk pieces. It will be painted with house paint or stained and sealed. These large objects would remain outdoors, in the sun... would there be any issues with gases, rain or sun exposer?
Hey no need to worry about that in California as the cost is 5 times more than in Florida for instance. It makes no cost sense to use it. My Florida home has closed cell and its the best for keeping the electric bills low and noise out.
I'm converting a portable building into a home, and after the wiring is done, insulation is next. Of course, everyone swears by whatever their preference happens to be. Most people I talk to say spray-in foam is the way to go, but I'm not sold. This demonstration was most educational - thank you.
I am a spray foam contractor in North Alabama and I agree with everything you said in this video. Well done. My only reservation is that maybe the foam and water would act differently with sheathing on one side as in a true application.
Love your videos Matt. As a student of construction management, these videos often teach me more information than the classes I have to take at school. Love to know what I am talking about on the jobsite. Thanks
A great practical demonstration that should cause concern for anyone considering spray foam under their roof deck. It appears that both open and closed foam can trap and hold water against the roof deck for an extended period. Obviously this raises the potential for wood rot. And with both materials the location of any trapped water may or may not be easily detected. As a result of this video, I am reconsidering the use of open cell foam against the roof deck for my upcoming house build.
DaveC I see your point but in my mind the risk out weighs the gain. The energy and air seal benefits out weight the leak risk. It is akin to saying we should not install drywall or wall insulation in case the siding fails. If a POTENTIAL leak is the concern we as an industry would look at ways to build a better roof not a poorer insulated home. There are always trade offs but this one can be overcome.
That is a good concern to have. One thought that came to mind is how often do people go through a routine check of potential rotting/leaking in these places that are hard to get to anyway? A major leak can be easy to detect quickly, but that slow, almost undetectable leak that happens over a long time, will probably cause damage regardless of what type of insulation, no?
I've been investigating this. I just had my roof replaced along with some sheething where the old 3 tab went bad (obviously in a hurricane ridden area). Either way, I've been looking at adding rafter baffles from the soffit to the ridge vent. This will still allow the roof to breathe and essentially keep the shingles cooler lengthening their lifespan. I plan on spraying over the baffles which will allow me to replace sheething easily if a leak ever develops. Granted, noticing the leak will be a concern when/if it happens.
Make sure you can get a mortgage on the house before hand before you foam inside of your roof. Banks, lenders can't inspect the roof and will not finance a sale if they can't confirm the roofs condition.
We just had litigation in my town in regarding a closed cell foam improperly installed. The installers filled 2x8 rafters completely full with foam. They installed it in the winter and now the summer heat has caused to foam to off gas and the house is uninhabitable. The foam company came back and removed the entirety of the foam and reinstalled the foam, but this time they sprayed in 3 rounds at 2” at a time and allowed off gassing at the thinner depth. The house has since been completed. Thanks to a ethical company the home owner wasn’t stuck with a house they couldn’t live in.
That is interesting because as an industrial hygienist who has studied the affects of these type products on human health, there is little to no impact on building occupants. That's not to say the homeowner wasn't happy with the smell. I'm just saying there isn't much from a health standpoint to be worried about.
It wasn't off gassing from spraying to thick that would cause this. You never spray closed cell more than 4in lifts because it can overheat and burn inside. The problem you describe would be from the ratio between the A and B side being off. Usually a good sprayer can see it while spraying and will stop but if it is barely fat enough off it can be missed. Good they had a company that did the right thing. Most foam companies will do that and are very ethical but every industry had a few who aren't ethical.
I have heard of this happening in other cases on the news. I was under the impression that if the closed cell foam is not mixed properly, then this is what can happen. And although some like to claim the gases are not toxic, they are very much toxic and harmful to human health. Thankfully, the company in this case pulled out the bad stuff and corrected the problem.
if the components mix is slightly off, it can actually cause some more serious issues, as well as smells. Not sure if that is the case here as we have no info, but in that case, the contractor would be liable. either way, if the company wasn't liable, they did the right thing by their customers, and that always comes back around in a positive way eventually.
They told me the same thing when I used it in the ceiling rafters but come to find out you're never going to find a leak through the open cell or the closed cell so I recommend using closed-cell all the way at least you get the structural strength from it
So should you spray waterproofing onto all your framing before applying closed cell spray foam? Would that prevent water from soaking through the wood joints, or should you apply caulking between every wood joint? Would closed cell foam stick to waterproofed wood surfaces? How about placing a sheet of clear plastic on your studs and joists, then nailing on your sheathing, then applying self-adhesive weather blocking? Would that be overkill?
On the build show!! That was a cool video. I am still wondering about foam because it seems like there are a lot of negative potentials and its very expensive. But its always good to learn more about it. Thanks Matt!
Arne Johansson Foam may cost more but it is one of the few building items that actually pays for itself in energy savings in a few years, depending on climate.
I’m in Houston and I have flooded twice. I had my house raised 4ft after hurricane Harvey. Recently I build a garage apartment and I am looking to protect my investment as best as possible, from future flooding. I am going to look into spraying my new garage with 2-3 feet of close cell.
I've always been curious, how does spray foam handle building settling for new construction? Will cracks appear, and you just have to go back and fill it with expanding foam in a can after a few years, or is it flexible enough that it will hold the air seal even with some building settling?
I had open cell foam sprayed under my sheathing and 14 years later when I reroofed my house (asphalt shingle roof was failing) I found some rot and there was no sign of water in the attic under those areas. I wanted to never have to reroof again so I personally installed a customized stainless steel roof.
I never heard of stainless steel roofing, but I have seen roofs that had spray foam right against the sheathing and the sheathing was totally dissolved and came off like wet cardboard. The south side was fine because it got enough heat to dissipate the moisture. It needs to have a vented air gap between the sheathing and the insulation in order to be sprayed up against the roof.
We have an older 51 yr old house that had no wall insulation at all, just hollow. Just had an open cell foam installed from the outside. Installed through brick on the bottom and aluminum on top. I can already tell the difference in the air being warmer. Solid foam was not possible. This gives about the same R value as fiberglass batts. Did not want to rip the walls out, this will not settle as cellulite does, and the end job was very clean. Highly recommend Cornerstone Insulation in The Salt Lake City, Utah area for price, quality, and professional application!
Matt, please note that the open cell foam was cut and the cellular structure of the insulation exposed to the water. Would closed cel foam react the same way if it was cut in a similar fashion?
Can you do any vids on residential geothermal systems and if you have radiant heat in concrete floors does it (over time) make the concrete more susceptible to cracking due to the heat speeding up curing?
Great job, this is probably the most useful video I have ever seen about polyurethane waterproof properties. Could you please make a video about the acoustic isolation properties? I would really appreciate it. Thanks in advance.
Closed cell foam will NOT help with acoustic isolation, I don't know about open cell, but I assume it would be better, due to it's less dense properties
The burning question I have is just that. What type of toxic fumes come off this stuff when it's burned? Is it deadly? Would you die faster in a fire if your house was insulated with it?
I was told that both open and closed cell will act as air barriers, while for vapor, open cell is never a vapor barrier. Closed cell is, once thicker than two inches. This from a certification course for sprayfoaming
Hello Matt, I am very skeptical about "24 hour" tests on foam. I have been around fiberglass boats since the late fifties and I can tell you that most were advertised (and still are) as close celled, much looked like isocyanurate while other colors and makes also were used. Bear in mind that these are sandwiched between layers of fiberglass being in theory fully adhered. Every single one stored in the water or in outside weather had varying degrees of water absorption. Some were literally soaked through. Water entered through mounting holes and sometimes at the 'shoe box' meeting of the deck and hull. To me that is quite an indictment for it to migrate so far from such small openings. This applies to above waterline structures as well as the hull below. The intrusion begins immediately and can reach full saturation in a few years. It will have to be seen in the long term (ten, twenty and more--how long do you want your house to last?) whether it actually performs as well as you say. I am a bit conservative when it comes to enclosing things in walls and would have to stay with mineral wool or fiberglass as of now and most especially so when it comes to price point (in low population rural areas it can get very very expensive!). Good topic for discussion. Take care. Doug
Both waterproof insulation on the face of the exposed basement walls to keep the water away because water takes away hydro static pressure from the wall thus making it weaker aswell as when that concrete cracks water will get into the crack and then you have serious issues. Best advice is save your money on the foam and fill the surrounding soil of your basement wall in gravel it will not allow water to build because it will just leak threw the cracks and crevices of the gravel.
never insuate ur foundation cut ur loses there u need to see whats happening structurally with ur house what if the wall is crumpling u will die before u know, think carefully don't listen to the moron everything new is good in his eyes use ur brain ur foundation is not a part u wanna fuk with u need to see whats happening to those areas
I have not seen much about synthetic stucco and sealing rim joists. Based on your comments at the end of the video it sounds like open cell would be fine in this situation. Since in the sand hills of North Carolina it is humid and I am double checking.
MATT!!!! Two hands on the saw!! My friend used a saw the same way you did and it jumped up out of the groove and cut his hand real bad. great video btw. thanks for sharing.
Interesting video thank you. Very practical method of demonstrating your point. In closed cell foam isn’t it vapor barrier? And open cell still requires a vapor barrier? I wonder why you aren’t putting two by four’s on top of the roof deck and spraying closed cell foam then putting a second decking over the top with ice and water shield the insulation will be on the outside your insurance company won’t be able to deny coverage for not being able to see the roof rafters and you still have the benefit of the insulation. Do you have any insurance questions about spray foam on the underside of the roof deck?
Very interesting for me to see this video. Kind of at a good time also. What would you do if your 'attic' area was also going to be sheet'ed over? Would you even risk foaming? Or use foam boards instead?
At an area close to atalanta . Working on a bonus room. It is a really pitched roof . Can I use foam on rafters and fiber glass on floor joists and what I saw you said to use open cell on rafters ?
I did my rim joists with 4" of closed cell followed by filling them up lots and all the cantilevers with open cell foam. That gave me the moisture and vapor barrier to the outdoors. You cant get a vapor barrier like that with plastic.
Thanks, Matt! This is fantastic analysis and clarifies many myths. The other part to this is vapor permeability with closed cell significantly more impermeable. I understand if two passes of closed cell will yield tighter envelop as the hard crust layer will act as vapor trap. Is this true?
They used to use open cell in boats for flotation. Now its closed cell only. Leave those outside for 10 years, and it will be night and day. If they had a recall on boats with open cell foam, the industry would have been sunk.⛵
I was advised to have closed cell spray foam sprayed directly onto my poured concrete basement walls (no studs)to concerve energy costs. My concrete walls occasionally leak in a few spots only when a heavy rain or a lot of snow melts. The worst spot is where an old cistern used to be. What will happen at those leak spots after the spray foam application is done? Is there any chance that mold will grow there?
Long time to wait for an. answer but ALL two part foams will absorb water if exposed over time. If you have any seepage in your wall your foam will absorb it. Do as search on flotation foam in boats. Tons of them with soaked foam. I would NEVER use this stuff for insulation in a home. Closed or open , no difference.
Question ??? I'm planning to do a closing cell on the ceiling of a bus , can I plaster over closing cell foam?? If yes , what is the best plaster material ? Thanks 😊
Matt, better question is if you need vapor barrier with open cell applied to roof. I found study saying 4" works as vapor barrier but that was only I source I found...
I did 4" closed cell on my rim joists then filled out to the walls and in the cantilevers with open cell for cost effectiveness and it gave me a perfect vapor barrier that you just cant get with plastic.
Great demonstration of what REALLY happens. I've heard horror stories about water penetration with both types of spray foam. Now I know what to watch out for and some mitigation ideas. Thx so much.
I wonder if a "leak point" would be a good choice for spray foaming rafter bays, similar to the weep holes in brick siding courses? A small diameter tube sprayed in place at the bottom of the rafter bay would release any trapped liquid water and act as an indicator of a leak, while indicating water entry into the bay from a leak. If you really wanted to get fancy and still avoid ceiling damage, run the bay's leak indicators together into a drain tube and terminate it at the eaves like some municipalities require for the AC auxiliary drain to be set up. When dripping shows a leak, pop the tubing free from the weep tubes and you can localize the leak point(s).
My experience is that smell slowly dissipates. The extremely dangerous gasses and fine particles stick around for 1-3 days. If sprayed correctly the smell should resolve within 3 months.
I did DIY closed cell and the smell went away in a day. Like paint, finish, and anything else that has to cure, just have to make sure not to spray full thickness in one pass.
I had a professional company do my home entirely in a combination of closed and open cell foam in different areas. they did 14" of open cell against the back side of the roof deck. 6 years later I can still smell the odor from the spray. From reading other comments it may sound like they should have done it in stages do let off the gases???
I plan to spray foam my attic, I’ve heard use open (different video). Seeing this demo, I like the close cell foam. Which one should I use? I live in the southwest.
Great video: Foam problem is you have guys installing it that last week were flipping burgers. When foam is sprayed to thick it will not cure properly ( Most times this is an attic issue ) and gasses and you will never find ANYONE to remove it not even the installer. Most times you need to remove the entire roof and ceiling joists and throw into the dumpster and reframe and finish everything which is super expensive. There are much better ways to get the same result without all the gassing of foam.
OK. PLEASE enlighten me. I live in a 1950 home. Remodeled in 1990's. They said they insulated WITH ROLL OUT BAT. & ATTIC HAS BLOW IN BAT? what u call it? but it's too winter cold & too summer hot. CAN I INSULATE UNDER THE FLOOR? WHAT WITH? HELP? PLEASE EDUCATE ME.
I watched my boss spray 2 bathrooms and a closet with the open cell spray foam packs you can buy at home depot. He didn't use a vapor barrier because he didn't understand the differences of foam. I wonder what those bathrooms are going to do in the winter 🤔. I'm in Alberta btw
Would close cell foam work as a subwoofer enclosure ? I'm wanting to put a subwoofer behind a rear panel in my land cruiser . There is not a lot of room and its a odd shape so I was think foam could fill in the space and I could cut out the inside of the foam once it set up to get the correct amount of air space .
My house is on a stilt foundation. The bottom of the house sits about 8 feet off the ground. You said closed cell would be better for the underside of a house but in my circumstance, would open cell be ok?
I wonder if closed cell foam would work on an undercarriage of a cargo trailer that im converting into a toy hauler. I will be using it in the winter to transport my atv. Roads may have the mag chloride. I wonder if it would stand up to mag chloride, slush, etc...
I live in S Florida and have a 1971 built concrete house - block walls and 6" slab decks and slab roof with elastomeric white roof coating. Zero Insulation. I have solar panels on stanchions and they are trapping heat between the panel and the roof, and the heat is passing through the roof. I've thought about laying tpo under the solar panels, but the time to cut/fit around all the stanchions, wiring, etc. is daunting. I'm wondering if a layer of spray foam insulation, topped with elastomeric roof paint might offer a solution. Any insight, experience, comments, welcomed.
Thanks Matt, your information presented and the comments from readers tends to lead me to use Roxul insulation tried and trusted for my barn rafters? I am sure spray foam open or closed is beneficial when applied properly but not in my rafters.
I used it in my new constructed cabin/cottage. If i were to do it again i would just air seal first then use typical kraft faced fiberglass insulation.
Hi Matt, I love all your videos and watch them often since I’ll be starting a new build in Spring. I live in the SW corner of Colorado, at about 7800 ft elevation. Are you familiar with the product called Icynene? It is a newer spray foam that has a castor oil plant base. I would like to know your opinion on it if you are familiar. Also, when doing spray foam in the attic, can the spray foam be put on the attic floor vs. the rafters? If so, what other precautions would need to be done?
Is it true you can use closed cell spray foam right up against a vaulted roof structure and not need to worry about venting or airflow through the roof structure?
And remember that any exposed area in the attic space are subject to condensation.. so spaces between the roof structure and ceiling, if any, still need to be vented.
Matt, Could you do a segment as to what it's like living in a super-sealed home? Say you fluid sealed the outside, closed celled the inside, caulked every piece of exterior lumber to the point that you killed the door testers because of the vacuum inside the home. You have the ERV set, but what happens when the wife leaves a tenacious bomber in the bathroom? Is the fart fan a standard CFM, or a smaller one? What about when cooking? Do you have to run the exhaust fan every time you use the range so the vapors don't enter the recycling HVAC air? Basically, what is the best practice in rapid venting in an air-tight home?
I literally laughed out loud at this...But you have a great point. This would be a good thing to look at. Possibly titled, "Building Science - How to clear a super-tight house of beer farts in an emergency situation."
Like your vids Matt. As a ResNet Rater, I've seen some pretty tight houses with open cell, but as a true green building fanatic, I'm personally not a fan of any foam. Thanks for the experiment though, it was informative.
Hey Jordan. Foam's performance as an insulator is great. But yes, I have an environmental objection with using it. Besides being petroleum based with high embodied energy, spray foam makes deconstructing these homes very difficult and cost prohibitive. This pretty much ensures that the entire wall assembly will end up in a land fill at the end of the home's life, rather than being reused. There is also a long-term durability concern: As Matt's experiment demonstrates, spray foam is likely to hide the presence of a leak, and even contribute to rotting if the foam forces the water to the joints and soaking into the wood, as was the case in this video. Which brings us to human health concerns. Wet wood attracts mold, which everyone knows is bad. Spray foam can off-gas for a long time, which is also bad for the inhabitants of a tight house. You can even find a few examples of botched spray foam jobs rendering homes inhabitable (hopefully more rare as the industry matures). Regardless, I kind of have a rule: anything requiring a hazmat suit during installation probably shouldn't be in my house. Despite my concerns, I do think foam products have a place in sustainable building. It does an excellent job air sealing around doors and windows, and that's fine with me because it's such a small amount compared to caking the whole roof deck. I also understand the need for northern climates to boost that R-value in the roof, in which case I would prefer foam board because it's created in quality controlled factory conditions. Foam board is also applied externally, which eliminates indoor air quality concerns, and still allows the home to be disassembled for reuse later. Sorry for the long reply, just love talking about this stuff. Cheers
Jeff Mathers thanks so much for your in depth response. I really appreciate it. I’ve built a few homes, the most recent with an airtight combination of open and closed form. I’m going to be building another one very soon and want to learn about all of the best technologies and practices these days. I will look further into all of this and if you have any further information Or links you can pass along I would greatly appreciate it.
Jordan Lane-Miller Good for you Jordan. My degree is in Sustainability management and I geared my curriculum towards green building as much I could. But I'm by know means an expert and I try to learn as much as I can. I just purchased a lot and planning my first (maybe only) house. I live in Florida so insulation doesn't have to be astronomical: planning about R-22 of dense-pack cellulose in the walls and R-40ish under the deck, not sure of what yet but I'm leaning towards mineral wool. I'm also planning to coat the sheathing with CAT-5 or similar product for my air/vapor barrier, and let it dry to the inside by swapping out the drywall with an interior wood siding. Haven't really seen anyone do this before so hopefully I won't end up with a soggy mess. I'm just going by what I've learned about how water and vapor behaves in my environment.
Also, as far as resources go, if you haven't already I would suggest looking up Hammer & Hand (hammerandhand.com). They do passive house homes near Seattle and have some great videos on the builds they've done (each build is a series of pretty in-depth videos). There's also the Green Building Advisor and Energy Vanguard, both of which have some great articles. Good luck man.
Matt Good tech on water characteristics of spray foam. Are you still using open cell in attic rafters w Carlisle 300HT underlayment for metal roof WRB in TX? BTW you would make a good Aggie by using a dead sawzall to cut through materials. Gig'em
Hi Matt ...Just ran onto your channel i live in SE North Carolina and have a new metal garage that i want to spray foam. Im thinking close cell for the ceiling and sides...your thoughts would like your opinion....thanks Chris
I live in north east Texas and have a metal garage, to save on money I was going to use 2in close cell ceiling (roof) and 6in open cell walls there is no vapor barrier just metal will I get condensation behind the open cell?
Great video but one major flaw in the comparison. At 2:07, you stated that you shaved the open cell foam but did not shave the closed cell foam. In other words, you cut the top off the cake. If you shaved the closed cell, would it eventually leak? Should compare apples to apples.
I am not sure. If it is much more than 200 boiard feet, it is likely best to have a pro do it since it wakes special equipment and the home kits are very expensive for the amount of foam you get.
Hey Matt do you think it would be appropriate to spray the underside of floors with a pier and beam construction? I'm down here in Victoria, TX and tons of old homes with nothing insulating the floors and often not even having a skirting under the house to have a dead air space. I'm just wondering if open cell would be okay to spray in between the floor joists under the house 12 inches or more above grade? Let me know what you think?
Alex Johnson Matt will be at the Humid Climate Conference next week.... So will Claudette Reichel, who you should Google. She just did a research report all about your question.
Like A.S. Enfield below I would like to know the fire resistant characteristics of each foam. Also what are there health risks concerning the vapors? If these products are used is an appropriate air barrier required? Can you use these two types of foam together? That is one or two inches of closed cell to get the water resistance an added structural value. Then add two or three inches of open on top of the closed cell for added R value? Great videos!
Closed Cell has a better R value but it is more expensive, that's a trade off. But does it have better fire proof/resistance qualities? Which, if any is more/less toxic? That is to say which needs a air barrier to prevent fumes into the conditioned space? I'm thinking a metal building for a house. I was thinking of foam for the insulation. Closed or open? This video and a few others have steered me away from open cell for condensation reasons. But now the concern is vapors/fumes from the closed cell. Of course the potential fire hazard is also something to be aware of. I like these types of videos because there is a take-away. But sometimes they bring up, or make folks aware of, other issues. So follow up videos ... keep the foam insulation saga going to it's conclusion.
Randall Nelson closed cell had the same odor as open cell and should be gone in about 24 hours. The fire hazard is really a moot point since if the interior of your walls are hot enough to cause the foam to burn then it is the least of your worries. Otherwise we always applied closed cell to metal buildings. Usually 1.5 to 3in was plenty. It glues the panels together and stops oil canning in wind making the metal about as stiff as .5in plywood.
If you're building a metal home the only good option is closed cell foam, that's literally what it was invented for back in the 60's. Any other insulation will have condensation occuring between the insulation and the metal causing problems down the road. With closed cell foam, condensation can not happen between it and the metal. Find a reputable spray foam company and off gassing or weird potential issues will not be a problem. It's really Almost impossible to spray bad (off ratio) foam with modern equipment, unless the installer chooses to ignore any equipment issue that might happen.
Also "R" value is an extremely misleading term.. an R14 of closed cell foam will outperform an R50 of fiberglass all day. Do a little research on insulation and read results and data from unbiased 3rd party tests that test various insulations in all kinds of different real world conditions.
I have a duplex that doesn't have a sound barrier between units. Could foam insulation be used spraying thru holes between studs? Would it do any good?
I wonder how open cell would do in a very humid environment, such as East Texas. Would it absorb moisture from the high humidity over time and hold that moisture like a sponge? Could that lead to rot in the adjacent studs?
It is class A fire rated and is self extinguishing unless the temperature is several hundred degrees. I had guys trying to argue it was dangerous to sell their junk fiberglass to people over foam all the time. By the time your walls are burning inside hot enough for foam to sustain a flame your carpet, couch, bed and the rest have already killed you and your body is a nice medium rare.
By the time the foam burns the house would be a total loss.. I co own a spray foam company, and I have done many burn tests on both open and closed cell foam, and it will burn when in contact with the flame of a map gas torch, but goes out as soon as the flame is removed.
i understand that this video is five years old, but isn't the better test one for water vapor permeability as water vapor can pass through some materials that are barriers to liquid water.
Always wondered if they made good contact in the corners; have never liked open cell foam. One doesn't have to be in construction to know it would absorb water. Have worked with other kinds of open cell foam in other applications and the wind would go right through it. I shouldn't think it would be any different for construction foam.
Nice to see honest and humble people still exist. 👌 nice video and thanks for the info found it helpful.
I use to be an applicator as I had my own employees and equipment when I was a new home builder to apply the closed cell foam. One thing you MUST know if you have a conscience and or have loved ones benefiting from the great insulation is that in the case of a house fire, even though the foam has or should have fire retardants , in the presence of flame the foam puts off cyanide gas. CYANIDE POISON gas. One breath of this stuff and you are incapacitated unlike regular smoky wood buildings. If you doubt me the chemical name for the cured foam is Poly-ISO-Cyanurate. Do you see the cyanide component ? That is one reason why all building codes require fire barriers covering all foam in areas that are inhabited. My family and relatives have saved many thousands of dollars in utility costs over the twenty years since I built their homes and they enjoy stupendous savings in heating and cooling as I went a little overboard in thickness since it was my own house and I was the wholesale applicator for myself. ie 2x6 exterior walls filled and 2x10s roof members filled in addition to R-25 batts above the ceiling and R 8 batts between floors as sound insulation. So be very very careful to not do stupid things that the insurance companies say cause 80 percent of all fires like Storing gas in garages with water heaters and burning candles and using cheap chimneys.
BTW, the entire marine and boating industry uses closed cell poly-iso-cyanurate ( poly-urethane ) foams as floatation in boats and floats because it will NOT soak up water.
Further there are off-gases immediately after spraying while curing that is
VERY TOXIC so make absolutely sure you have large fans blowing
for ventilation and you must vacate the house for at least 24 hours after spraying and be sure to provide plenty of ventilation.
I had an applicator that inhaled too much of the off-gas and he had to go to hospital intensive care for 2 days because of suffering pulmonary edema. ( swelling around lungs and heart that prevents breathing and intake of oxygen from the air.)
This seems like a lot of negative but this foam is absolutely magic when it comes to saving money... Your dwelling can become futuristic thermal spaceships if properly taken advantage of. I just wanted to fill in with some important missed but critical details.
I really really appreciate your comment. I'm looking to used ccSPF as an air sealant / vapour barrier in my attic before adding blown in cellulose insulation...I've also seen horrific videos of families having to move out of their homes because of off gassing....I'm really reluctant to use it as an air sealer but it's what everyone is recommending.
great info Scott, thanks for sharing
Thank you for the comment!! I plan to use it for crafting waterfall. I will be outside but I have COPD. I will NOW wear a mask!!!!
Hey Scott, I am planning on using the foam for some outdoor projects, that would be the foam in bulk pieces. It will be painted with house paint or stained and sealed. These large objects would remain outdoors, in the sun... would there be any issues with gases, rain or sun exposer?
Hey no need to worry about that in California as the cost is 5 times more than in Florida for instance. It makes no cost sense to use it. My Florida home has closed cell and its the best for keeping the electric bills low and noise out.
I'm converting a portable building into a home, and after the wiring is done, insulation is next. Of course, everyone swears by whatever their preference happens to be. Most people I talk to say spray-in foam is the way to go, but I'm not sold. This demonstration was most educational - thank you.
I am a spray foam contractor in North Alabama and I agree with everything you said in this video. Well done. My only reservation is that maybe the foam and water would act differently with sheathing on one side as in a true application.
Picture framing stud bays with spray foam to close air gaps and using rockwool as the main insulation is the way to go. Or go with SIPs.
Love your videos Matt. As a student of construction management, these videos often teach me more information than the classes I have to take at school. Love to know what I am talking about on the jobsite. Thanks
Glad I came across this video. Thank you for comparing and sharing.
A great practical demonstration that should cause concern for anyone considering spray foam under their roof deck. It appears that both open and closed foam can trap and hold water against the roof deck for an extended period. Obviously this raises the potential for wood rot. And with both materials the location of any trapped water may or may not be easily detected. As a result of this video, I am reconsidering the use of open cell foam against the roof deck for my upcoming house build.
DaveC I see your point but in my mind the risk out weighs the gain. The energy and air seal benefits out weight the leak risk. It is akin to saying we should not install drywall or wall insulation in case the siding fails. If a POTENTIAL leak is the concern we as an industry would look at ways to build a better roof not a poorer insulated home. There are always trade offs but this one can be overcome.
That is a good concern to have. One thought that came to mind is how often do people go through a routine check of potential rotting/leaking in these places that are hard to get to anyway? A major leak can be easy to detect quickly, but that slow, almost undetectable leak that happens over a long time, will probably cause damage regardless of what type of insulation, no?
I've been investigating this. I just had my roof replaced along with some sheething where the old 3 tab went bad (obviously in a hurricane ridden area). Either way, I've been looking at adding rafter baffles from the soffit to the ridge vent. This will still allow the roof to breathe and essentially keep the shingles cooler lengthening their lifespan. I plan on spraying over the baffles which will allow me to replace sheething easily if a leak ever develops. Granted, noticing the leak will be a concern when/if it happens.
But the time you see a roof leak that bad it will show in ceiling fix the leak fix the foam absurd reason not use foam
Make sure you can get a mortgage on the house before hand before you foam inside of your roof. Banks, lenders can't inspect the roof and will not finance a sale if they can't confirm the roofs condition.
We just had litigation in my town in regarding a closed cell foam improperly installed. The installers filled 2x8 rafters completely full with foam. They installed it in the winter and now the summer heat has caused to foam to off gas and the house is uninhabitable. The foam company came back and removed the entirety of the foam and reinstalled the foam, but this time they sprayed in 3 rounds at 2” at a time and allowed off gassing at the thinner depth. The house has since been completed. Thanks to a ethical company the home owner wasn’t stuck with a house they couldn’t live in.
That is interesting because as an industrial hygienist who has studied the affects of these type products on human health, there is little to no impact on building occupants. That's not to say the homeowner wasn't happy with the smell. I'm just saying there isn't much from a health standpoint to be worried about.
Bonnd T, that is true, but it doesn't make the contractor liable.
It wasn't off gassing from spraying to thick that would cause this. You never spray closed cell more than 4in lifts because it can overheat and burn inside. The problem you describe would be from the ratio between the A and B side being off. Usually a good sprayer can see it while spraying and will stop but if it is barely fat enough off it can be missed.
Good they had a company that did the right thing. Most foam companies will do that and are very ethical but every industry had a few who aren't ethical.
I have heard of this happening in other cases on the news. I was under the impression that if the closed cell foam is not mixed properly, then this is what can happen.
And although some like to claim the gases are not toxic, they are very much toxic and harmful to human health.
Thankfully, the company in this case pulled out the bad stuff and corrected the problem.
if the components mix is slightly off, it can actually cause some more serious issues, as well as smells. Not sure if that is the case here as we have no info, but in that case, the contractor would be liable. either way, if the company wasn't liable, they did the right thing by their customers, and that always comes back around in a positive way eventually.
They told me the same thing when I used it in the ceiling rafters but come to find out you're never going to find a leak through the open cell or the closed cell so I recommend using closed-cell all the way at least you get the structural strength from it
Really enjoy these in-depth videos with demonstrations. I would be interested in seeing more focused versus videos like this one.
Good approach. I would suggest to dip both the foams in coloured liquid for 24 hrs and slice it laterally to understand the seepage characterics.
So should you spray waterproofing onto all your framing before applying closed cell spray foam? Would that prevent water from soaking through the wood joints, or should you apply caulking between every wood joint? Would closed cell foam stick to waterproofed wood surfaces? How about placing a sheet of clear plastic on your studs and joists, then nailing on your sheathing, then applying self-adhesive weather blocking? Would that be overkill?
Finally the answer I was looking for, thank you 😊
In the south, with the high humidity, if spraying roof raters with open cell, do you need to spray a vapor barrier after the foam installation?
Short answer is you never ever ever use open cell where moisture is an issue. Boat hulls and insulation.. no open cell.
Thank you Matt, pros and cons to all insulation!
On the build show!! That was a cool video. I am still wondering about foam because it seems like there are a lot of negative potentials and its very expensive. But its always good to learn more about it. Thanks Matt!
Arne Johansson Foam may cost more but it is one of the few building items that actually pays for itself in energy savings in a few years, depending on climate.
I’m in Houston and I have flooded twice. I had my house raised 4ft after hurricane Harvey. Recently I build a garage apartment and I am looking to protect my investment as best as possible, from future flooding. I am going to look into spraying my new garage with 2-3 feet of close cell.
I've always been curious, how does spray foam handle building settling for new construction? Will cracks appear, and you just have to go back and fill it with expanding foam in a can after a few years, or is it flexible enough that it will hold the air seal even with some building settling?
Very good question. The answer is that It cracks.
What noise dampening characteristics do these products have?
Quite revealing. Great information. I was under the impression as well that open cell would allow you to detect roof leaks.
I had open cell foam sprayed under my sheathing and 14 years later when I reroofed my house (asphalt shingle roof was failing) I found some rot and there was no sign of water in the attic under those areas. I wanted to never have to reroof again so I personally installed a customized stainless steel roof.
Shld have sprayed closed cell
Mike Oxmall hindsight is always 20/20
I love metal roofs! My current house has one and I never have to worry about leaks.
I never heard of stainless steel roofing, but I have seen roofs that had spray foam right against the sheathing and the sheathing was totally dissolved and came off like wet cardboard. The south side was fine because it got enough heat to dissipate the moisture. It needs to have a vented air gap between the sheathing and the insulation in order to be sprayed up against the roof.
@@astoltzfus4,
They must have had a leaky roof for the sheathing to get wet. Venting is not needed if the roof dose not leak, but it is better.
Why am I watching this I don’t even own a house
Thats funny you mention that I don’t ones one also..bud still watching this, still interesting to see
Knowledge is Power
😂
I’m watching this because i have a boat!
Because you are smart and will build a house with all the metals (especially Silver) that you bought low and sold stupid high.
We have an older 51 yr old house that had no wall insulation at all, just hollow. Just had an open cell foam installed from the outside. Installed through brick on the bottom and aluminum on top. I can already tell the difference in the air being warmer. Solid foam was not possible. This gives about the same R value as fiberglass batts. Did not want to rip the walls out, this will not settle as cellulite does, and the end job was very clean. Highly recommend Cornerstone Insulation in The Salt Lake City, Utah area for price, quality, and professional application!
How's it holding up?
Excellent scientific test you've done ✔. Great work on proving the point.
Great info, thanks. Any thoughts on application on metal roof, south Texas???
Great demo. Trying to decide how to insulate a camper van conversion.
What did you go with?
Matt, please note that the open cell foam was cut and the cellular structure of the insulation exposed to the water. Would closed cel foam react the same way if it was cut in a similar fashion?
I was talking with a spray foam contractor and he tries to not cut/shave the open cell because he says it does resist water a bit better...
Does anyone have information about the polyurethane foam іnsulation after many years of operation?
Thanks foe the video. Question. Were you speaking just about exterior?
Would open cell be ok to use below grade for the interior?
Can you do any vids on residential geothermal systems and if you have radiant heat in concrete floors does it (over time) make the concrete more susceptible to cracking due to the heat speeding up curing?
Love these tests. Thank you for educating the community.
Great job, this is probably the most useful video I have ever seen about polyurethane waterproof properties.
Could you please make a video about the acoustic isolation properties?
I would really appreciate it.
Thanks in advance.
Closed cell foam will NOT help with acoustic isolation, I don't know about open cell, but I assume it would be better, due to it's less dense properties
You just made up my mind to spend the 10k for the closed cell in my 30x60x12 ALL metal building. Thanks Matt !
How did this work out for you. I’m putting up a 30x60 and I’m debating the insulation I should use.
I am glad that you helped the people in texas
The burning question I have is just that. What type of toxic fumes come off this stuff when it's burned? Is it deadly? Would you die faster in a fire if your house was insulated with it?
I would have liked to know a little more about the vapor or air difference between the two types of foam.
I was told that both open and closed cell will act as air barriers, while for vapor, open cell is never a vapor barrier. Closed cell is, once thicker than two inches. This from a certification course for sprayfoaming
Hello Matt, I am very skeptical about "24 hour" tests on foam. I have been around fiberglass boats since the late fifties and I can tell you that most were advertised (and still are) as close celled, much looked like isocyanurate while other colors and makes also were used. Bear in mind that these are sandwiched between layers of fiberglass being in theory fully adhered. Every single one stored in the water or in outside weather had varying degrees of water absorption. Some were literally soaked through. Water entered through mounting holes and sometimes at the 'shoe box' meeting of the deck and hull. To me that is quite an indictment for it to migrate so far from such small openings. This applies to above waterline structures as well as the hull below. The intrusion begins immediately and can reach full saturation in a few years. It will have to be seen in the long term (ten, twenty and more--how long do you want your house to last?) whether it actually performs as well as you say. I am a bit conservative when it comes to enclosing things in walls and would have to stay with mineral wool or fiberglass as of now and most especially so when it comes to price point (in low population rural areas it can get very very expensive!). Good topic for discussion. Take care. Doug
For basement with concrete walls do you still need foam insulation. If yes do i use it inside of the wall or outside
Both waterproof insulation on the face of the exposed basement walls to keep the water away because water takes away hydro static pressure from the wall thus making it weaker aswell as when that concrete cracks water will get into the crack and then you have serious issues. Best advice is save your money on the foam and fill the surrounding soil of your basement wall in gravel it will not allow water to build because it will just leak threw the cracks and crevices of the gravel.
never insuate ur foundation cut ur loses there u need to see whats happening structurally with ur house what if the wall is crumpling u will die before u know, think carefully don't listen to the moron everything new is good in his eyes use ur brain ur foundation is not a part u wanna fuk with u need to see whats happening to those areas
I have not seen much about synthetic stucco and sealing rim joists. Based on your comments at the end of the video it sounds like open cell would be fine in this situation. Since in the sand hills of North Carolina it is humid and I am double checking.
MATT!!!! Two hands on the saw!! My friend used a saw the same way you did and it jumped up out of the groove and cut his hand real bad. great video btw. thanks for sharing.
Interesting video thank you. Very practical method of demonstrating your point.
In closed cell foam isn’t it vapor barrier? And open cell still requires a vapor barrier?
I wonder why you aren’t putting two by four’s on top of the roof deck and spraying closed cell foam then putting a second decking over the top with ice and water shield the insulation will be on the outside your insurance company won’t be able to deny coverage for not being able to see the roof rafters and you still have the benefit of the insulation. Do you have any insurance questions about spray foam on the underside of the roof deck?
Very interesting for me to see this video. Kind of at a good time also. What would you do if your 'attic' area was also going to be sheet'ed over? Would you even risk foaming? Or use foam boards instead?
At an area close to atalanta .
Working on a bonus room.
It is a really pitched roof .
Can I use foam on rafters and fiber glass on floor joists and what I saw you said to use open cell on rafters ?
Love your channel....I live in NYC and if I use closed cell for rim joists, do I run the same risk of wood rot if any leaking?
Yes
I did my rim joists with 4" of closed cell followed by filling them up lots and all the cantilevers with open cell foam. That gave me the moisture and vapor barrier to the outdoors. You cant get a vapor barrier like that with plastic.
My Brother put open cell in a boat that had holes in it and the foam took in water many years later he checked the foam it still was soaked through.
It seems that you could use the open cell for maximum coverage if you could find some kind of water proofing to top it off with.
@Matt Risinger what are your thoughts on this spray foam nightmare video news coverage? Makes me leery of going anywhere near the stuff?
Thanks, Matt! This is fantastic analysis and clarifies many myths. The other part to this is vapor permeability with closed cell significantly more impermeable. I understand if two passes of closed cell will yield tighter envelop as the hard crust layer will act as vapor trap. Is this true?
They used to use open cell in boats for flotation. Now its closed cell only. Leave those outside for 10 years, and it will be night and day. If they had a recall on boats with open cell foam, the industry would have been sunk.⛵
I was advised to have closed cell spray foam sprayed directly onto my poured concrete basement walls (no studs)to concerve energy costs. My concrete walls occasionally leak in a few spots only when a heavy rain or a lot of snow melts. The worst spot is where an old cistern used to be. What will happen at those leak spots after the spray foam application is done? Is there any chance that mold will grow there?
Long time to wait for an. answer but ALL two part foams will absorb water if exposed over time. If you have any seepage in your wall your foam will absorb it. Do as search on flotation foam in boats. Tons of them with soaked foam. I would NEVER use this stuff for insulation in a home. Closed or open , no difference.
Question ??? I'm planning to do a closing cell on the ceiling of a bus , can I plaster over closing cell foam??
If yes , what is the best plaster material ? Thanks 😊
Matt, better question is if you need vapor barrier with open cell applied to roof. I found study saying 4" works as vapor barrier but that was only I source I found...
tompaj10 depends on climate zone. Only required in 5-8. Open cell is never a class II (less than 1 perm) vapor retarder.
5 inches open r19 attic must be sealed completely
I did 4" closed cell on my rim joists then filled out to the walls and in the cantilevers with open cell for cost effectiveness and it gave me a perfect vapor barrier that you just cant get with plastic.
So, proper application is key to closed cell foam, especially at the corners.
Great demonstration of what REALLY happens. I've heard horror stories about water penetration with both types of spray foam. Now I know what to watch out for and some mitigation ideas. Thx so much.
Is the open cell damaged or will it dry out and be back too good?
I was doing electrical work at a house that had just gotten open cell insulation and it started leaking when it rained
I wonder if a "leak point" would be a good choice for spray foaming rafter bays, similar to the weep holes in brick siding courses? A small diameter tube sprayed in place at the bottom of the rafter bay would release any trapped liquid water and act as an indicator of a leak, while indicating water entry into the bay from a leak. If you really wanted to get fancy and still avoid ceiling damage, run the bay's leak indicators together into a drain tube and terminate it at the eaves like some municipalities require for the AC auxiliary drain to be set up. When dripping shows a leak, pop the tubing free from the weep tubes and you can localize the leak point(s).
How long does it take for the smell to go away after foaming a house? I went in one with all the windows open and it stunk so bad I had to get out.
My experience is that smell slowly dissipates. The extremely dangerous gasses and fine particles stick around for 1-3 days. If sprayed correctly the smell should resolve within 3 months.
No more than 2 days
I did DIY closed cell and the smell went away in a day. Like paint, finish, and anything else that has to cure, just have to make sure not to spray full thickness in one pass.
Smell should be gone within a couple hours max
I had a professional company do my home entirely in a combination of closed and open cell foam in different areas. they did 14" of open cell against the back side of the roof deck. 6 years later I can still smell the odor from the spray. From reading other comments it may sound like they should have done it in stages do let off the gases???
I plan to spray foam my attic, I’ve heard use open (different video). Seeing this demo, I like the close cell foam. Which one should I use? I live in the southwest.
Great video: Foam problem is you have guys installing it that last week were flipping burgers. When foam is sprayed to thick it will not cure properly ( Most times this is an attic issue ) and gasses and you will never find ANYONE to remove it not even the installer. Most times you need to remove the entire roof and ceiling joists and throw into the dumpster and reframe and finish everything which is super expensive. There are much better ways to get the same result without all the gassing of foam.
OK. PLEASE enlighten me.
I live in a 1950 home. Remodeled in 1990's.
They said they insulated WITH ROLL OUT BAT. & ATTIC HAS BLOW IN BAT? what u call it?
but it's too winter cold & too summer hot.
CAN I INSULATE UNDER THE FLOOR? WHAT WITH?
HELP? PLEASE EDUCATE ME.
Thin layers boys even when pouring.
I watched my boss spray 2 bathrooms and a closet with the open cell spray foam packs you can buy at home depot. He didn't use a vapor barrier because he didn't understand the differences of foam.
I wonder what those bathrooms are going to do in the winter 🤔.
I'm in Alberta btw
Would close cell foam work as a subwoofer enclosure ? I'm wanting to put a subwoofer behind a rear panel in my land cruiser . There is not a lot of room and its a odd shape so I was think foam could fill in the space and I could cut out the inside of the foam once it set up to get the correct amount of air space .
My house is on a stilt foundation. The bottom of the house sits about 8 feet off the ground. You said closed cell would be better for the underside of a house but in my circumstance, would open cell be ok?
Great test Mat. Very thorough. Great work.
Can closed cell foam be sprayed over the vapor barrier of rolled fiberglass insulation as is commonly installed in a red steel building?
I wonder if closed cell foam would work on an undercarriage of a cargo trailer that im converting into a toy hauler. I will be using it in the winter to transport my atv. Roads may have the mag chloride. I wonder if it would stand up to mag chloride, slush, etc...
It would as well or better that anything
I live in S Florida and have a 1971 built concrete house - block walls and 6" slab decks and slab roof with elastomeric white roof coating. Zero Insulation. I have solar panels on stanchions and they are trapping heat between the panel and the roof, and the heat is passing through the roof. I've thought about laying tpo under the solar panels, but the time to cut/fit around all the stanchions, wiring, etc. is daunting. I'm wondering if a layer of spray foam insulation, topped with elastomeric roof paint might offer a solution. Any insight, experience, comments, welcomed.
Thanks Matt, your information presented and the comments from readers tends to lead me to use Roxul insulation tried and trusted for my barn rafters? I am sure spray foam open or closed is beneficial when applied properly but not in my rafters.
Great video! You should be on TV!
ON TARIO people still watch TV? Lol
Haha, some people I know. I don't have cable though.
Was thinking of putting closed cell foam on the bottom of an rv? Can I get your opinion on that application?
I used it in my new constructed cabin/cottage. If i were to do it again i would just air seal first then use typical kraft faced fiberglass insulation.
Hi Matt, I love all your videos and watch them often since I’ll be starting a new build in Spring. I live in the SW corner of Colorado, at about 7800 ft elevation. Are you familiar with the product called Icynene? It is a newer spray foam that has a castor oil plant base. I would like to know your opinion on it if you are familiar. Also, when doing spray foam in the attic, can the spray foam be put on the attic floor vs. the rafters? If so, what other precautions would need to be done?
Which one should I use in a cooler to keep things HOT?
Is it true you can use closed cell spray foam right up against a vaulted roof structure and not need to worry about venting or airflow through the roof structure?
Yup. But remember any liquid leaking from the roof will be trapped against the wood.
And remember that any exposed area in the attic space are subject to condensation.. so spaces between the roof structure and ceiling, if any, still need to be vented.
What is your thoughts on the ABC or 20/20 show. That showed the families that had spray foam done and got sick.
Joe Haynes that was a mistake due to the installer making the mix a bit off
Matt,
Could you do a segment as to what it's like living in a super-sealed home? Say you fluid sealed the outside, closed celled the inside, caulked every piece of exterior lumber to the point that you killed the door testers because of the vacuum inside the home. You have the ERV set, but what happens when the wife leaves a tenacious bomber in the bathroom? Is the fart fan a standard CFM, or a smaller one? What about when cooking? Do you have to run the exhaust fan every time you use the range so the vapors don't enter the recycling HVAC air?
Basically, what is the best practice in rapid venting in an air-tight home?
I laughed, I cried, I enjoyed the shaping up to a sharply made point.
Set it up just like those fire place inserts with a separate combustion air inlet except that the fart bomb doesn't combust.
I literally laughed out loud at this...But you have a great point. This would be a good thing to look at. Possibly titled, "Building Science - How to clear a super-tight house of beer farts in an emergency situation."
By regulation, indoor air quality requires a 20% changeover with "fresh" outside air once every hour. You'll get sick if you don't have that.
SO make the 20% changeover outlet vent from the toilets and range hood!
What about the drying of studs/wood after build and closed-cell foam then pulling away… destroying air envelope?
You should be required watching for every residential contractor (and structural engineer)!
That’s really kind. Thanks !
Like your vids Matt. As a ResNet Rater, I've seen some pretty tight houses with open cell, but as a true green building fanatic, I'm personally not a fan of any foam. Thanks for the experiment though, it was informative.
thanks for your comment. Are you not a fan of any foam because it is not "Environmentally friendly" or because of it's performance, etc?
Hey Jordan. Foam's performance as an insulator is great. But yes, I have an environmental objection with using it. Besides being petroleum based with high embodied energy, spray foam makes deconstructing these homes very difficult and cost prohibitive. This pretty much ensures that the entire wall assembly will end up in a land fill at the end of the home's life, rather than being reused.
There is also a long-term durability concern: As Matt's experiment demonstrates, spray foam is likely to hide the presence of a leak, and even contribute to rotting if the foam forces the water to the joints and soaking into the wood, as was the case in this video.
Which brings us to human health concerns. Wet wood attracts mold, which everyone knows is bad. Spray foam can off-gas for a long time, which is also bad for the inhabitants of a tight house. You can even find a few examples of botched spray foam jobs rendering homes inhabitable (hopefully more rare as the industry matures). Regardless, I kind of have a rule: anything requiring a hazmat suit during installation probably shouldn't be in my house.
Despite my concerns, I do think foam products have a place in sustainable building. It does an excellent job air sealing around doors and windows, and that's fine with me because it's such a small amount compared to caking the whole roof deck. I also understand the need for northern climates to boost that R-value in the roof, in which case I would prefer foam board because it's created in quality controlled factory conditions. Foam board is also applied externally, which eliminates indoor air quality concerns, and still allows the home to be disassembled for reuse later.
Sorry for the long reply, just love talking about this stuff. Cheers
Jeff Mathers thanks so much for your in depth response. I really appreciate it. I’ve built a few homes, the most recent with an airtight combination of open and closed form. I’m going to be building another one very soon and want to learn about all of the best technologies and practices these days. I will look further into all of this and if you have any further information Or links you can pass along I would greatly appreciate it.
Jordan Lane-Miller Good for you Jordan. My degree is in Sustainability management and I geared my curriculum towards green building as much I could. But I'm by know means an expert and I try to learn as much as I can. I just purchased a lot and planning my first (maybe only) house. I live in Florida so insulation doesn't have to be astronomical: planning about R-22 of dense-pack cellulose in the walls and R-40ish under the deck, not sure of what yet but I'm leaning towards mineral wool. I'm also planning to coat the sheathing with CAT-5 or similar product for my air/vapor barrier, and let it dry to the inside by swapping out the drywall with an interior wood siding. Haven't really seen anyone do this before so hopefully I won't end up with a soggy mess. I'm just going by what I've learned about how water and vapor behaves in my environment.
Also, as far as resources go, if you haven't already I would suggest looking up Hammer & Hand (hammerandhand.com). They do passive house homes near Seattle and have some great videos on the builds they've done (each build is a series of pretty in-depth videos). There's also the Green Building Advisor and Energy Vanguard, both of which have some great articles. Good luck man.
Matt Good tech on water characteristics of spray foam. Are you still using open cell in attic rafters w Carlisle 300HT underlayment for metal roof WRB in TX? BTW you would make a good Aggie by using a dead sawzall to cut through materials. Gig'em
Thank you Scott. That is good information to know.
Hi Matt ...Just ran onto your channel i live in SE North Carolina and have a new metal garage that i want to spray foam. Im thinking close cell for the ceiling and sides...your thoughts would like your opinion....thanks Chris
I live in north east Texas and have a metal garage, to save on money I was going to use 2in close cell ceiling (roof) and 6in open cell walls there is no vapor barrier just metal will I get condensation behind the open cell?
Great video but one major flaw in the comparison. At 2:07, you stated that you shaved the open cell foam but did not shave the closed cell foam. In other words, you cut the top off the cake. If you shaved the closed cell, would it eventually leak? Should compare apples to apples.
Great stuff to know. Thank you for sharing.
All of this convinced me that I would never apply spray foam directly to the underside of roof sheathing.
How well would the closed cell work with concrete and block homes???
Cruz Marin works great on them and metal buildings too. We did a lot of metal buildings through word of mouth praise on it.
Quentin Durrstein how could i get a insulation kit sent to mexico
I am not sure. If it is much more than 200 boiard feet, it is likely best to have a pro do it since it wakes special equipment and the home kits are very expensive for the amount of foam you get.
Quentin Durrstein cool thank you
They have specialty foam you inject into block drill holes actually good product reducing heat bridge
Hey Matt do you think it would be appropriate to spray the underside of floors with a pier and beam construction? I'm down here in Victoria, TX and tons of old homes with nothing insulating the floors and often not even having a skirting under the house to have a dead air space. I'm just wondering if open cell would be okay to spray in between the floor joists under the house 12 inches or more above grade? Let me know what you think?
Alex Johnson Matt will be at the Humid Climate Conference next week.... So will Claudette Reichel, who you should Google. She just did a research report all about your question.
What would happen if you had a foundation leak with closed cell? Would the water just run down the wall? How would you get to the leak to fix it?
Like A.S. Enfield below I would like to know the fire resistant characteristics of each foam.
Also what are there health risks concerning the vapors? If these products are used is an appropriate air barrier required?
Can you use these two types of foam together? That is one or two inches of closed cell to get the water resistance an added structural value. Then add two or three inches of open on top of the closed cell for added R value?
Great videos!
Closed cell is better R value
Closed Cell has a better R value but it is more expensive, that's a trade off. But does it have better fire proof/resistance qualities?
Which, if any is more/less toxic? That is to say which needs a air barrier to prevent fumes into the conditioned space?
I'm thinking a metal building for a house. I was thinking of foam for the insulation. Closed or open? This video and a few others have steered me away from open cell for condensation reasons. But now the concern is vapors/fumes from the closed cell. Of course the potential fire hazard is also something to be aware of.
I like these types of videos because there is a take-away. But sometimes they bring up, or make folks aware of, other issues. So follow up videos ... keep the foam insulation saga going to it's conclusion.
Randall Nelson closed cell had the same odor as open cell and should be gone in about 24 hours. The fire hazard is really a moot point since if the interior of your walls are hot enough to cause the foam to burn then it is the least of your worries.
Otherwise we always applied closed cell to metal buildings. Usually 1.5 to 3in was plenty. It glues the panels together and stops oil canning in wind making the metal about as stiff as .5in plywood.
If you're building a metal home the only good option is closed cell foam, that's literally what it was invented for back in the 60's. Any other insulation will have condensation occuring between the insulation and the metal causing problems down the road. With closed cell foam, condensation can not happen between it and the metal. Find a reputable spray foam company and off gassing or weird potential issues will not be a problem. It's really Almost impossible to spray bad (off ratio) foam with modern equipment, unless the installer chooses to ignore any equipment issue that might happen.
Also "R" value is an extremely misleading term.. an R14 of closed cell foam will outperform an R50 of fiberglass all day. Do a little research on insulation and read results and data from unbiased 3rd party tests that test various insulations in all kinds of different real world conditions.
I have a duplex that doesn't have a sound barrier between units. Could foam insulation be used spraying thru holes between studs?
Would it do any good?
do you know of a caulking type foam that swells only a very little bit and then remains VERY soft and spongy when cured ?
I wonder how open cell would do in a very humid environment, such as East Texas. Would it absorb moisture from the high humidity over time and hold that moisture like a sponge? Could that lead to rot in the adjacent studs?
In use in fort Myers if someplace is more humid, you tell me
Is 'Great Stuff' closed cell? What brands that come in consumer cans are closed and open cell.
Would you recommend closed or open for northern Tennessee? In between Knoxville and Nashville.
Hi Matt. Can you do a video on how this stuff burns. I see foam sprayed hoses and think that is a disaster waiting to happen.
A.S Enfield Dr Energy Saver has a video on just that, compared to other insulations as well
A.S Enfield a disaster waiting to happen is your carpet, couch, bed, etc.
But your Precious Moments figurines should be fine
It is class A fire rated and is self extinguishing unless the temperature is several hundred degrees. I had guys trying to argue it was dangerous to sell their junk fiberglass to people over foam all the time. By the time your walls are burning inside hot enough for foam to sustain a flame your carpet, couch, bed and the rest have already killed you and your body is a nice medium rare.
By the time the foam burns the house would be a total loss.. I co own a spray foam company, and I have done many burn tests on both open and closed cell foam, and it will burn when in contact with the flame of a map gas torch, but goes out as soon as the flame is removed.
Wow, thank you Matt
i understand that this video is five years old, but isn't the better test one for water vapor permeability as water vapor can pass through some materials that are barriers to liquid water.
Always wondered if they made good contact in the corners; have never liked open cell foam. One doesn't have to be in construction to know it would absorb water. Have worked with other kinds of open cell foam in other applications and the wind would go right through it. I shouldn't think it would be any different for construction foam.