Good job calling out how poor or misguided workmanship and lack of understanding of the building science leads to poor outcomes. I'm glad you're doing this work to help builders make fewer mistakes, less waste and better performing homes.
Unfortunately, especially in spec houses there is quite a bit of poor and/or misguided workmanship. The risk is that a significant number of bad spray foam installs (particularly in climates that are very cold or very humid) will give the rest a poor reputation and cause increasing difficulty in getting insurance or mortgages. In practical terms the perception can be as much of a problem as the reality.
@@benz-share9058I want to reiterate this. For all this to work four contractors need to know what they are doing with spray foam. Being on job sites where the trades are out back smoking pot and basically putting the minimum effort into their work, where the subcontractor himself only shows up every other day to inspect his workman’s work . . . .this in Houston aint gonna work out well. We have far less sophisticated systems that essentially. The framing contractors, the decking contractor, the foam applicator, the attic ventilation system, the roof deck and roofer. Matt even made a video on how this foam collects moisture at the peak, you got to know what you are doing to prevent it.
I'm in Scotland, which is part of the UK, and we've recently put Kingspan between our rafters with an air gap so moisture can escape and not rot the wood. The issue is really as your second point - older houses here have no vapour barrier in the roof so small amounts of moisture do make it through. Spray foam here was frequently put in by dodgy firms looking to make a quick buck, and they would just fill the space in the rafters, which will trap moisture as the cold air hits the warmer air of the foam and condensate, rotting the roof at the condensation line.
Hi from UK. Really interested to see this video Matt. Our Health & Safety Executive (HSE) have just issued a report on spray foam (no idea why as there is no H&S implication). They say that the risk of rot varies according to roof construction, type of foam and and climate, but if done properly is not a problem. Open cell seems to be preferred here, theory is so that moisture from below can pass through newer style breathable membrane as opposed to traditional impervious bitumen underfelt plus double height roof battens to ventilate under the slate / tile.roof. The HSE also advise open cell. Nothing is said about thickness or whether rafters should be covered..Vapour barriers unclear. Its just a mess. I read that just one senior surveyor set this hare running, as he came across a couple of rotten roofs, and now everyone is running scared. The standard foam thickess used here is only about 4". There is a bad history of closed cell being applied directly onto the underside of tiled or slated old roofs to "hold it all together" to keep the roof going past its life. Thats not good. Cowboy operators bolstered by well-meaning government grants, have applied the wrong foam in the wrong sort of roof in the incorrect way, and badly. Building techniques in UK have been changing, warm roofs are now a thing but that is fairly new. The more common traditional cold roofs need lots of through ventilation, with only 300mm rockwool type insulation on the loft floor. Lots of strong anti-foam opinion over here!
That lines up with so many stories I have heard from England on buildings. The regulators are extremely slow to address new tech, and by the time they do there are huge issues. And very aggressive opinions on it. Like your comment on closed foam, it is great stuff if used correctly and not to cover up structural or other issues like you pointed out. So now closed has a bad rep because of it.
@@darkshardrex7589 UK doesn't do prescriptive design codes. It's very subjective with objectives you should produce. And as the Grenfell Tower Fire showed, there are a lot of people in the UK confidently doing design and construction very wrong. who are overseen by inspectors who apparently have no idea what they are doing and standards bodies in the pocket of manufacturers.
The problem I have encountered repeatedly in the US is that finding a good installer is incredibly difficult. It’s hard to know if people are doing things correctly unless you yourself are an expert. Had a mini split install recently where contractor made a subtle mistake welding the line set and this caused thousands of dollars in damage to the cassettes. The install LOOKS great. Inspector didn’t think to ask about it. My concern is that mortgage brokers and insurance may lump everyone together and cause problems for modern homes no matter if Matt built it or not.
I just made a comment about the lumping together. Big companies seem to do this quicker. Might have to seek smaller insurance co's to get coverage. Good to still be able to get coverage but limiting options isn't great.
Matt, here along the Gulf Coast in the US, non-native Formosan Termites are causing a LOT of problems. And the closer to the water you live the worse it is. Recently, I wanted to upgrade the insulation in our attic from fiberglass bats to spray foam. But I quickly found out that our termite company (Terminix) would drop us (cancel the bond) if we installed spray foam - for fear of trapped moisture which would in turn attract termites. Called other pest control companies and they said the same thing. Talk to your builder buddies in Houston about this. It is a BIG deal along the coast as every single home on or near the water has had a Formosan termite infestation. The Formosan termite colonies are an order of magnitude larger than normal subterranean termites and so they eat a lot of wood in a short time.
I've never seen any insects in foam. I have seen it in every other type of bat insulation. They love to nest in that stuff and once it gets wet it never drys out.
I think you missed the comment where she said that she had black mould prior to the install. That is very common here, and indicates that there was already a problem with condensation to start with. The high humidity here means that people don't really trust wood buildings. One of the issues was the way that the grants were structured - it encouraged companies to quickly do a lot of installations with minimal / no training of the staff, and no consequences if something went wrong. So it did not matter to them whether or not the roof rotted afterwards.
Cheers from Canada. Been a guy who has built 2 - R2000 homes - 20yrs before they were adopted. Working on a NET ZERO. heavy insulation wall and ceiling, Double 1980 standards. It was a response by NBPOWER executives to the 73 OPEC crisis . Our area - is - 50 F. We need to release water - and decrease moisture into the house. For years - I have used - forced air movement. Thank you MATT - cheers!
I used to use a lot of spray foam. Then we did a reno on a house that had what should have been a pretty minor roof leak, but because the foam trapped the moisture between sheathing and the foam it turned into a catastrophic amount of damage. There are still situations where it is almost a must, but we use it sparingly.
This is the problem with closed cell insulation, you don't see a roof leak. So, open cell allows condensation to rot the roof, while closed cell allows a roof leak to accumulate moisture. Insulation above the roof helps keep the wood from being cold enough to condense. Open cell below it helps a roof leak to be visible instead of rotting the structure. There are roofers in the US who won't repair a roof with spray foam below the roof line.
Hi from the UK, the UK gov has a history of 'insulation' programs that are used as ways to make jobs. A lot of people who dont have skills end up with low paid jobs insulating houses, there are good people doing it but there's also a bunch that pop up just to sock up the government money before the deadline ends. It always ends up with a lot of problems, it's a rush to get the grant money over a real care for the work.
Spray foam doesn't work well in homes built 100+ years ago, because the home was literally built to breathe to dry out. It is a very different concept that we have today. Air flow in walls used to be encouraged, so that you wouldn't have mold. The issue is that this was a fire hazard as well. If you take a balloon wall construction from the 1800s and the roof framing that comes with that, and you button everything up with open cell foam, you will get condensation on the wood and eventually it will rot.
2 inches of closed cell foam then I went across the studs with aluminum double bubble and then taped it all off. 12 years ago. No problems. I did not close up the attic. it was vented and had 2 windows. Cut my heating bill by 80%. needed a/c 2 weeks out of the year. Never saw a bug ever again. Never heard my neighbors ever again.
I kinda have this debate often with people online. Spray foam is fine but you need to do a bunch of work first to make it acceptable, it’s best on new construction.
There was also an episode of Holmes on Homes, or another Mike Holmes show I believe where they removed everything due to the spray foam installer spraying the foam too thick up in the attic, thus it would never fully cure and was slowly constantly outgassing, which was making everyone in the home sick.
As an upper in builder in Middle Tennessee, I will not not spray a roof rafter. It can hide a minor roof leak. We have spray foamed ceiling joists that abuts the attic, weather it be a 1 story or 2 story home. We normally use R38 for the ceiling below the attic and sometimes use rock wool. Never had an issue. I cannot speak for northern climates however since Middle Tennessee's winters are mild.
I used aluminum double bubble on all my ceilings taped it down to the walls. and Never put a dime's worth of insulation in my attic,. This is in south new jersey. The attic is vented. Any moisture build up goes out the attic I have never had a problem and my heating bill was cut by 80%...
This is a good episode. I always have thought that spray foam may be good to warm an old house up, but might not be the best thing for an older home. If you design a new home and take moisture in to consideration then you're probably ok with spray foam. People often overlook rock wool, which is an excellent insulation and sound barrier for older homes. I own a 70 year old house in zone 4 and the roof rafters are 1x6, so I doubt I could get spray foam to work for me. I've focused on other things like rock wool, and other types of ceiling insulation, and replacing windows and doors with modern tech to get the energy efficiency that I need.
You want to kill the chimney effect first. Spray Foam The sill. Then the walls. I put aluminum double bubble across my rafters which were doubled up 2x4s on balloon framing. Then did the same to the walls and tapped all the corners and seams off. I didn't condition the attic. It has 2 windows and a ridge vent. I've Never had a moisture build up in the house. It all went out through the attic or never came in. Cut my heating bill by 80%...
I live in South Florida and I have had to do WDO inspections for home refinance. There has been issues with homeowners Who have put in spray foam insulation and cannot get bank approval. For the most common reason of it, making it inaccessible to see if there is or was termite damage that's being hidden/ iconcealed by the insulation. It also prevent us from being able to treat the exposed wood throughout the attic in a preventive fashion against wood destroying organisms using profucts like bora-care or premise2.
This reminds me of a video you released about 3 years titled "I’m recommending we NOT INSULATE This Old House" The historical context and designs used on these old english homes is not being taken into consideration when adding insulation. They could even have these issues with normal rockwool or fiberglass insulation if installed in the same way.
Another comment regarding moisture control: It’s my position that you will never be able to completely keep moisture out. Even if you did, I’m convinced the seal would fail over time. A “tight” house is a trap for moisture. Instead, I focus on what I call “moisture management.” I assume moisture will get in - so I make sure there’s a Way for the moisture to get out. For example, I advocate installing siding with a small gap between the siding and the moisture barrier. That way, any moisture that gets in can drain out. I ensure there’s a clear air path on the underside of the roof, from attic vents to ridge vent.
I put a layer of ridged foam between the decking and spray foam. If the decking needs replaced we should be able to peal the bad decking off without touching the spray foam. Time will tell though
Before I watch the rest (I'm only 2 seconds into the interview), Im going to veture a guess that (like everything else HVAC related in GB) they are doing it wrong; Government subsidies caused a bunch of businesses to spring up overnight without proper understanding, training or expertise and a whole lot of salesmanship (backed by government messaging). Now back to it, let's t see how my prediction holds up.
I concur. We had our city mandate on homeowners to put water pressure regulator. They said that if we do it within two months, we can get reimbursement, but if we don't, later on we will have to foot the bill. They even gave us suggestions which companies to call. After install, it needed to be inspected by the city inspector. I called and guy was send to our house in 2 days. I checked during those days about total cost and the highest price for top tier back then was $95. City stated that they will reimburse up to $850. Notice word "up to". The guy came, did it in 15min and charged us .... yes you guessed it, $850. Then magically city Inspector for which the wait time is usually over a month, showed up 2 hrs after job was done. We both went into crawl space and thank God he came so fast (although I found out later that they scratching each other's backs). The water was dripping and since we always had bucket sitting under crawlspace water shut off valve, I had already about 1 /4 of gallon of water in a bucket. I panicked and told the Inspector that I will call the guy to get his butt back right away to fix the leaking issue and a da... Inspector tells me " don't bother him, it will be ok. In time the dirt and and grease from the surrounding area will plug up the connection and act as seal and stop the leak. I know that guy and he is always doing a great job". That's when my red flag went up. The city inspectors and other officials were directing people to their buddies because there was "free" money flying around. I told his that I don't give a crap since I paid $850 for job that took 15 min and part for $95 (they probably had further discount) and based on travel cost of the company and per Hr labor, should cost on high end even if charging 1 hr labor, no more than $550. I called the guy back. He came back ticked off. This time I watched him like a hawk and it took him less then 7 min to fix it and no leak after that. I was furious because this city reimbursement money didn't come off the tree, it came for property taxes from all of us. People who couldn't afford to pay upfront costs and be home magically waiting during the week day hour for installer, got screwed.
i feel really bad for these homeowners who had no idea about the science with spray foam. the government who pushed this 'fix' should definitely reimburse them for this error. with that said, as i understand it, the lenders not extending mortgages to these homes only if it applies to retrofits without engineering. they are mortgaging homes that have been retrofitted with engineering sign off and new construction with engineering as well. so as long as the ventilation, vapor transport mechanisms, and materials used are accounted for and engineered, there should be no issues.
@@elgringoec as is the case with anything engineered... but within the scope of mortgages, i believe lenders will extend mortgages to engineered retrofits.
I live in NYC and there are a lot of old houses here that got spray foam due to an incentive a few years back. So, I can see it becoming an issue in some areas, because it was a money grab for some of the insulation companies without much consideration for building science.
While properly installed closed cell insulation with no leaks will solve the problems from vapor condensation, It can greatly increase the risks from bulk water from above when the roof fails. Yes, some people replace the roof when a periodic roof inspection indicates that the roof is close to end of life, many people first thought of roof replacement is when the brown stain in the ceiling gets larger and may take a year or more to figure out how to pay for it when they get an estimate of the cost. By that time, it won't just need a few pieces of roof sheathing replaced, it will need much more sheathing which is still glued to the insulation where it hasn't rotted to mulch and roof rafters with it. Won't it be fun to rebuild those trusses. Much of this damage will be done before any water gets through the closed cell foam to leave the brown stain on the ceiling.
Having lived in the UK for over a decade, coming from continental Northern Europe, the type and quality of construction in the UK is shocking. It’s not only the cold climate, it’s the year-round humidity, and that they absolutely weren’t building for it. Your comment that some house are “under-insulated” made me choke. There are buildings here as recent as 40 years old that have either 2-3 brick thick solid walls, or a 2 brick thick wall with a totally empty cavity in between. No underfloor insulation, no roof insulation, just the expectation of cheap natural gas for all eternity. To the point that the only way to adequately dry out your house is to have heating on 24/7. The spray foam roof insulation ‘scandal’ is the result of an endemic culture of short-sightedness coming home to roost, not only once (when originally built), but twice (when foam was installed). New requirements here finally got higher air tightness and requirements for mechanical ventilation (ERV/MVHR), but even then the homeowner rarely understands what it’s for, what it does or how it’s supposed to work… much less maintains it properly.
We closed cell spray most of our projects here (Washington DC area). Never had a problem. But we subcontract it out and the installer is really excellent.
Matt, most of the pre 1920 properties in England are slate or clay tile fixed on timber (lumber) battens fixed directly to the top of the rafters with no underlay, roofs then started to include a layer of roofing felt below the battens with this becoming the norm from about 1950. The use of timber sarking boarding above the rafters was generally only used on higher quality/status buildings, it has only become more common on domestic building recently, especially where there is habitable accommodation within the roof space. Spray foam only really began to be used in England from the 1980's and then generally only for retro fitting, its use mushroomed about 20 years ago when there were government grants available for installing insulation to older properties, this attracted many unscrupulous installers with little building science knowledge to promote it for totally inappropriate situations who then often had very poor inhalation procedures.
Good video, the conclusions are good. You are low balling the humidity in the UK. Depending on time of year and location it can vary between 50% to 90%. Most roof construction is roofing felt on top of the rafters you see in the videos with batten nailed on top of that to hang the tiles from (tiles are nailed as required by building regulations) so not a lot between the cold tile and the inside of the roof space, nothing you would recognise as a deck. The big problem with this sort of work is the government grants for it. Companies will convince people that the the new (funded) thing is good for them and do the work, then get paid by the government irrespective of whether or not the house is suitable for the work or not. This behaviour repeats with each new government initiative to improve the (elderly) housing stock of the country.
I'm in the process of converting my flat ceiling to a vaulted ceiling. I watched how you've used 2in closed cell and then finished with open cell on top of that. I live in NW North Dakota borderline zone 8. Do you recommend using this method for my area? Thanks Matt! I love your videos!!
I agree with you on "shorts". The viewer has no idea what was left out. Sometimes the exclusion is innocuous. But more often, it's leading you to the conclusion the author wants you to make. It's easy to manipulate a "short". It seems like England has a problem with properly selling spray foam. i.e. "We can do a job with closed cell phone but open cell costs only 1/3 of that." WRONG OFFER, especially in cold and rainy old England....I wonder what the average nighttime humidity is.
Yes, that's the case, manipulation can be the goal. It's like playing a clip where someone says "there are fine people on both sides" and leaving out the part "and I'm not talking about the neo Nazis" so dishonest people can say the person called neo Nazis fine people. Same basic tactic.
I agree with you and like your comment. Question: Are you also a bit older? I only say that because I have been a building contractor for about four decades and have seen many products not hold out as represented. A popular product "PEX"warranties 25 years, copper 50 years. 25 years is not very long buried in a wall of your home.
Absolutely correct. I live in an 80+ year old home and have been able to renovate and repair much of it because it’s all accessible ( water damaged fiberglass insulation, insulation in the wrong places, leaking pipes, substandard electrical wiring, etc.). If any of this was inaccessible, we’d be looking at a demolition and rebuild. Radiant heating embedded in concrete? You are putting a lot of trust in something that will be a nightmare to fix if it fails.
@@fsoileau I respectfully disagree with your Plumbing analogy. We don’t know the lifespan of PEX yet. Just because the warranty is set for 25 years doesn’t mean it’s not good for longer. We’ve all seen copper lines that are well over 50 years and are perfectly fine.
I have seen copper lines that were installed touching a dissimilar metal and have corrosion to the point of failure. It comes down to how it is installed same as PEX
I think a lot of the issue is the type of roof that is typically used in the UK. Ceiling tiles directly over purlins without waterproofing barrier, thatched roof, etc. These roofs leak, and with spray foam applied, keeps the moisture on the wood rafters causing the issues
That house looks more like 90-100 years old rather than 40. Roof structures in UK are generally very different to US. "Under insulated" is an understatement. Recommended ceiling insulation in UK is 300mm (12"). Normal is fibreglass. Tiled rooves on tar paper with battens is normal and as you say relatively breathable. Your homes in the US are very different.
Insulation in the UK is generally very poor to non-existent in many houses, and I don't mean to stereotype, but most people's solution is to just put on a sweater and drink a hot cup of tea.
The only problem with spray foam is bad installers. That's why I won't use it, because I don't trust anyone to do it right. Right mixture, right thickness, right coverage, right temperature, right amount applied in one area at a time, right dehumidiication system, right home to begin with. Most installers don't underatand half of the required variables to create a safe install.
Agreed. Installer quality seems like a major variable. However, a procedure that is easy to do wrong, and when done wrong can lead to catastrophic failure, doesn't sound like a good choice.
11:00 Another thing that you don't mention and is relevant is the fact that the UK has a rather humid climate year round. They can basically expect some rain every other day.
Open or closed is bad for roofs. Issue is that if the roof has a leak, its make be impossible or very difficult to locate it. Water will pool & rot the roof. Either batts or cut peices of rigid foam panels should be used instead. You can always remove them for inspector or roof repair. I suspect in the next 3 to 7 years there are going to be a lot of US homes that need roof replacement caused by spray foam.
I find it interesting that in the UK lenders obviously do some sort of inspection. I have bought and refinanced a relative LOT of real estate here in the US, in several states over the past 25 years and not once EVER has a lender done that. They get an appraisal report, but that says nothing at all about the specific methods of construction, only an opinion of the value. And my home in Maine is more than 200 years old in part (no spray foam though).
Matt, you are also missing a weird thing about UK homes and that is that they have water tanks in their attic. They have very low water pressure because of old pipes in the ground so they have to have water tanks in the attic to supply the house. I am sure that causes even more mosture in the attic that here in the USA.
My 1970s home has mains pressure water (about 3 bar) - hot and cold, no gravity feed. Old central heating boiler had an expansion tank in the loft but that was removed and it's now a pressurised system. That's a lot more normal than tanks in the loft these days.
I have an old (1890s) home in Michigan and would love a video about insulating the attic. Was going to go with Rockwool for the breathability. I'm under the impression that any spray foam (closed or open) would potentially have issues with moisture. You seem to elude to closed cell, done correctly, wouldn't. To me a mineral wool seems pretty fool proof, provided I can get my desired R-value in the current space of my rafters. Plus the noise reduction and pest deterrent seem like positive secondary benefits
One assumption I see being made here is that if the outside temperature is 30 degrees the roof will also be the same temperature. This will be approximately correct at night if there is cloud cover blocking the infrared radiated into space by the roof. If there is no cloud cover the roof will be significantly colder than the outside air temperature because the roof is radiating infrared energy into space. Over time the cold roof will cool the air temperature. This will of coarse be affected by any heat leaking from the building envelope into the attic.
In the U.S. lenders and insurance companies can calculate their potential losses from spray foam. Many homes will have no problems and a small number will require huge amount of remediation. The larger risk is the current abysmal quality of brand new production homes on a massive scale: dangerous framing, cardboard sheathing, window failures, substandard electrical, plumbing, roofs, foundation preparation, etc. These problems have the potential for billions of dollars in losses.
Thing is we have a lot of insulation companies starting to do this same thing over here in 40-70yo houses, or recommending it. People just need to understand the science of moving the envelope from the ceiling to the roof deck and we need smart people managing that instead of just saying "Spray it!".
The issue is spray foam is being used to cover up structural issues and mold. It can also trap moisture. Nearly all homes in Europe are 1970's or earlier built.
Spray foam is highly toxic. Burns like gasoline. If it separates you’re gonna have water mold issues. Skilled trades are lacking in skills & conscientiousness these days. Seems like a terrible product. Unless it’s perfectly installed and you like breathing chemicals Insurance companies are pushing hard to make people homeless and to grab properties and close down residential areas; Florida, Hawaii, Nc, Tn. It might be okay in dry places but for the Norht East it seems terrible. It’s the same concept as EiFis that foam fiberglass nonsense that rotted houses Just cause it works doesn’t mean a house shouldn’t breathe. Fuel costs are not everything. If you wanted the best house ever it would be made of concrete on all surfaces but yet we build with wood. Let the house breath and use mineral wool.
From my research you can't just "retrofit" spray foam onto a roof attic as you need to account for the roof structure and load. My trusses my be able to support the extra weight but with air flow would be a factor so it would need to be re-engineered to account for that.
That might be one reason they went with OCF it's light, and there's not much snow load there so OCF ought to be within the capabilities of any reasonably framed roof. CCF is several times denser.
A building with a top hat (uninsulated roofline) is insurance. Turn or treat your attic as conditioned space with foam and the underlayment roof barrier had better be PERFECT or your foam will hide a leak until it's too late. I do not understand why that risk is taken. The issue is that the foam is functionally treated as if it's also a sealer no matter where it goes. There have been decades of black, soggy fiberglass batts that were treated the same way, with the same results. At least with batts you can yank it out in SECONDS if necessary. Please think of repairability, not just quick efficiency in the moment when everything is still shiny and new.
Matt, we are thinking of doing open cell spray foam in our conditioned attic assembly. We live in Oklahoma. We couldn’t afford rigid foam on the deck. Would you recommend a taped smart vapor retarder at the bottom of the joists after the foam?
This makes me a little nervous as we are building a barndo with wood frame and steel siding and roof and were thinking that closed cell foam is really the only way to combat the condensation on the steel. Is there a better way to do it? And should we put tyvek between the steel and the wood frame, or just apply the foam straight to the steel?
My issue with spray foam is the “what if” factor. Yes, you can engineer a solution that works if everything is done right and goes right for decades. But what if something is done slightly wrong? What if something fails at some point 20 years later? Complex systems need to handle non ideal conditions to be durable. Spray foam, as great as it is when done right leaves you 0 margin of error. You’re setting yourself up for possible (likely) disaster at some point in the future. People can choose if that’s worth it to them. I don’t think it is for me. Especially when you can build assemblies that perform 80-90% as well, cost less and have the ability to withstand non-ideal conditions.
Probably needed to make it a conditioned attic or at least install a dehumidifier. But also, proper installation of the foam and proper foam would have been the best foundation.
A building, any building, has to be designed as a whole. Modifying it willy-nilly is asking for trouble. Taking the advice of a bunch of UK politicians is always a bad idea
I can't imagine a good scenario for me to use spray foam. Whatever benefit it may have in insulating properties is less than my desire to inspect, maintain, change, etc.
Seems the problem is installing Any insulation in the rafters without either reserving a soffit vent-to-ridge vent air channel above for drying or completely sealing the lower surface of the insulated layer from vapor transmission (or both). Rockwool in the rafters without these measures taken will still allow warm moisture thru to the roof sheathing where it will condense on the underside. And additionally as someone else mentioned a dehumidifier should probably be installed in these sealed attics as well anyways.
Any thing that one has to wear a respiratory to install can't be good at any time I'm building a home and they said we'll spray foam the jost cell, lol I had asked to not to spray foam them I'll rockwool them myself, I plan to Valkum caulk the joints and pack it with rockwool
Gotta love insulation. And with the IRC 2021 codes, now they're requiring R-60 in the roof, which I am sure is going to have a lot of builder's turning to foam, since the R values per inch are higher than batt. For years, R-38 worked just fine, then they went to R-49 for a couple years, and now ... well now, I have to wonder who is in who's pocket selling insulation? R-60 might be required in Alaska, but Virginia?
Don’t forget that you are not required to use foam. You can easily get to R 60 with a very cheap blown fiberglass or cellulose as long as you pay attention to air ceiling between the house and the attic, and definitely don’t have any ductwork up there.
Working on this now in Massachusetts, we are using 4 inches of reclaimed eps foam board on the roof with rockwool batt insulation. Price is comparable with closed cell spray foam even with the increased sheathing costs
Not sure Matt is appreciating just how many older homes here are getting the attic foamed treatment. Its quite a few in areas without a lot of new development. Foamed roofs with complicated rooflines prone to leakage is going to be a pretty big problem. Also need to remind that sometimes the Insurance co's don't care that your roof was foamed properly. They are going to lump you in with everyone with a foamed roof.
I wonder if stupidity, ignorance, and carelessness was as common in the past as it is now? Because it seems like that every other person in a trade or service is an incompetent huckster out for money at their customer's expense. My parents were constantly victimized by idiots and frauds claiming they could build/repair/refurbish/clean etc...
If it cant dry, its gonna die. In the event water does get in, the foam will never let the framing dry. Ive seen this happen to sprayfoam and fiberglass and plastic vapor barrier. From what i gathered The sprayfoam case was caused by not caulking the windows. And the other was an old barn where the exposed fasteners were beyond their lifespan in combination with being overgrown with trees and shrubs. Read: lack of maintenance. Id even say maintenance in both cases. Whereas the customer who had his barn foamed never checked or recaulked his windows. Love what you are doing Matt. Less the foam and engineered lumber, i dont enjoy breathing in glue dust.
A guy I know works for Aqua Barrier. He showed me pictures of a crawlspace under a home that had been sprayed with foam (open or closed I don't know. Assuming open). The house had to be demolished because the sub structure had all rotted out. I'd love to use foam in future projects but can't figure out what information to trust.
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Good job calling out how poor or misguided workmanship and lack of understanding of the building science leads to poor outcomes. I'm glad you're doing this work to help builders make fewer mistakes, less waste and better performing homes.
Unfortunately, especially in spec houses there is quite a bit of poor and/or misguided workmanship. The risk is that a significant number of bad spray foam installs (particularly in climates that are very cold or very humid) will give the rest a poor reputation and cause increasing difficulty in getting insurance or mortgages. In practical terms the perception can be as much of a problem as the reality.
@@benz-share9058I want to reiterate this. For all this to work four contractors need to know what they are doing with spray foam. Being on job sites where the trades are out back smoking pot and basically putting the minimum effort into their work, where the subcontractor himself only shows up every other day to inspect his workman’s work . . . .this in Houston aint gonna work out well. We have far less sophisticated systems that essentially.
The framing contractors, the decking contractor, the foam applicator, the attic ventilation system, the roof deck and roofer. Matt even made a video on how this foam collects moisture at the peak, you got to know what you are doing to prevent it.
I'm in Scotland, which is part of the UK, and we've recently put Kingspan between our rafters with an air gap so moisture can escape and not rot the wood. The issue is really as your second point - older houses here have no vapour barrier in the roof so small amounts of moisture do make it through. Spray foam here was frequently put in by dodgy firms looking to make a quick buck, and they would just fill the space in the rafters, which will trap moisture as the cold air hits the warmer air of the foam and condensate, rotting the roof at the condensation line.
What is Kingspan?
I like rockwool. Spray foam makes a mess to go in and renovate modify years later, plus fireproofing is a giant difference between them
Hi from UK.
Really interested to see this video Matt. Our Health & Safety Executive (HSE) have just issued a report on spray foam (no idea why as there is no H&S implication).
They say that the risk of rot varies according to roof construction, type of foam and and climate, but if done properly is not a problem.
Open cell seems to be preferred here, theory is so that moisture from below can pass through newer style breathable membrane as opposed to traditional impervious bitumen underfelt plus double height roof battens to ventilate under the slate / tile.roof. The HSE also advise open cell. Nothing is said about thickness or whether rafters should be covered..Vapour barriers unclear. Its just a mess.
I read that just one senior surveyor set this hare running, as he came across a couple of rotten roofs, and now everyone is running scared. The standard foam thickess used here is only about 4".
There is a bad history of closed cell being applied directly onto the underside of tiled or slated old roofs to "hold it all together" to keep the roof going past its life. Thats not good.
Cowboy operators bolstered by well-meaning government grants, have applied the wrong foam in the wrong sort of roof in the incorrect way, and badly.
Building techniques in UK have been changing, warm roofs are now a thing but that is fairly new. The more common traditional cold roofs need lots of through ventilation, with only 300mm rockwool type insulation on the loft floor. Lots of strong anti-foam opinion over here!
That lines up with so many stories I have heard from England on buildings. The regulators are extremely slow to address new tech, and by the time they do there are huge issues. And very aggressive opinions on it.
Like your comment on closed foam, it is great stuff if used correctly and not to cover up structural or other issues like you pointed out. So now closed has a bad rep because of it.
@@darkshardrex7589 UK doesn't do prescriptive design codes. It's very subjective with objectives you should produce. And as the Grenfell Tower Fire showed, there are a lot of people in the UK confidently doing design and construction very wrong. who are overseen by inspectors who apparently have no idea what they are doing and standards bodies in the pocket of manufacturers.
and that's the truth.
I just don't get why the UK can't learn from decades of experience in other jurisdictions.
You pretty much got it spot on. Good explanation. We have very different houses in the UK. Mostly clay tiles, poor insulation.
People don't understand how important proper ventilation is.
It's an unvented roof assembly.
Lived in the UK for a bit, can confirm. Huge caveat, the UK builds homes very differently than the US.
exactly.
The problem I have encountered repeatedly in the US is that finding a good installer is incredibly difficult. It’s hard to know if people are doing things correctly unless you yourself are an expert. Had a mini split install recently where contractor made a subtle mistake welding the line set and this caused thousands of dollars in damage to the cassettes. The install LOOKS great. Inspector didn’t think to ask about it. My concern is that mortgage brokers and insurance may lump everyone together and cause problems for modern homes no matter if Matt built it or not.
I just made a comment about the lumping together. Big companies seem to do this quicker. Might have to seek smaller insurance co's to get coverage. Good to still be able to get coverage but limiting options isn't great.
Welding the line set on a mini split??? 🤔😯
Matt, here along the Gulf Coast in the US, non-native Formosan Termites are causing a LOT of problems. And the closer to the water you live the worse it is. Recently, I wanted to upgrade the insulation in our attic from fiberglass bats to spray foam. But I quickly found out that our termite company (Terminix) would drop us (cancel the bond) if we installed spray foam - for fear of trapped moisture which would in turn attract termites. Called other pest control companies and they said the same thing. Talk to your builder buddies in Houston about this. It is a BIG deal along the coast as every single home on or near the water has had a Formosan termite infestation. The Formosan termite colonies are an order of magnitude larger than normal subterranean termites and so they eat a lot of wood in a short time.
Good to know, I was always a little sceptical about this.👍🏝️🇨🇦
😯
I've never seen any insects in foam. I have seen it in every other type of bat insulation. They love to nest in that stuff and once it gets wet it never drys out.
I think you missed the comment where she said that she had black mould prior to the install. That is very common here, and indicates that there was already a problem with condensation to start with. The high humidity here means that people don't really trust wood buildings.
One of the issues was the way that the grants were structured - it encouraged companies to quickly do a lot of installations with minimal / no training of the staff, and no consequences if something went wrong. So it did not matter to them whether or not the roof rotted afterwards.
Cheers from Canada. Been a guy who has built 2 - R2000 homes - 20yrs before they were adopted. Working on a NET ZERO. heavy insulation wall and ceiling, Double 1980 standards. It was a response by NBPOWER executives to the 73 OPEC crisis . Our area - is - 50 F. We need to release water - and decrease moisture into the house. For years - I have used - forced air movement. Thank you MATT - cheers!
Check out “ this old house-net zero bungalow, season40” believe it was based in Rhode Island, not as cold as you wrote but was a pretty cool build.
I used to use a lot of spray foam. Then we did a reno on a house that had what should have been a pretty minor roof leak, but because the foam trapped the moisture between sheathing and the foam it turned into a catastrophic amount of damage. There are still situations where it is almost a must, but we use it sparingly.
question: why don't they put a drainage plane like dimple mat from eves to ridge vent?
This is exactly why I don’t use spray foam. Roof leaks are inevitable, and if you can’t see them you get a catastrophic mess
@@johnpowers1125 I'm glad I have a standing seam metal roof where the risk of leaks are very low.
@@BobPritchard I was thinking the same thing, when I do my next build I will do (Zip*closed cell)standing seam metal roof. Good call
This is the problem with closed cell insulation, you don't see a roof leak. So, open cell allows condensation to rot the roof, while closed cell allows a roof leak to accumulate moisture.
Insulation above the roof helps keep the wood from being cold enough to condense. Open cell below it helps a roof leak to be visible instead of rotting the structure. There are roofers in the US who won't repair a roof with spray foam below the roof line.
Hi from the UK, the UK gov has a history of 'insulation' programs that are used as ways to make jobs. A lot of people who dont have skills end up with low paid jobs insulating houses, there are good people doing it but there's also a bunch that pop up just to sock up the government money before the deadline ends.
It always ends up with a lot of problems, it's a rush to get the grant money over a real care for the work.
One of your most informative videos….thanks for sharing
Glad it was helpful!
Spray foam doesn't work well in homes built 100+ years ago, because the home was literally built to breathe to dry out. It is a very different concept that we have today.
Air flow in walls used to be encouraged, so that you wouldn't have mold. The issue is that this was a fire hazard as well.
If you take a balloon wall construction from the 1800s and the roof framing that comes with that, and you button everything up with open cell foam, you will get condensation on the wood and eventually it will rot.
2 inches of closed cell foam then I went across the studs with aluminum double bubble and then taped it all off. 12 years ago. No problems. I did not close up the attic. it was vented and had 2 windows. Cut my heating bill by 80%. needed a/c 2 weeks out of the year. Never saw a bug ever again. Never heard my neighbors ever again.
I kinda have this debate often with people online. Spray foam is fine but you need to do a bunch of work first to make it acceptable, it’s best on new construction.
There was also an episode of Holmes on Homes, or another Mike Holmes show I believe where they removed everything due to the spray foam installer spraying the foam too thick up in the attic, thus it would never fully cure and was slowly constantly outgassing, which was making everyone in the home sick.
as a foam applicator your correct
As an upper in builder in Middle Tennessee, I will not not spray a roof rafter. It can hide a minor roof leak. We have spray foamed ceiling joists that abuts the attic, weather it be a 1 story or 2 story home. We normally use R38 for the ceiling below the attic and sometimes use rock wool. Never had an issue. I cannot speak for northern climates however since Middle Tennessee's winters are mild.
I used aluminum double bubble on all my ceilings taped it down to the walls. and Never put a dime's worth of insulation in my attic,. This is in south new jersey. The attic is vented. Any moisture build up goes out the attic I have never had a problem and my heating bill was cut by 80%...
This is a good episode. I always have thought that spray foam may be good to warm an old house up, but might not be the best thing for an older home. If you design a new home and take moisture in to consideration then you're probably ok with spray foam. People often overlook rock wool, which is an excellent insulation and sound barrier for older homes. I own a 70 year old house in zone 4 and the roof rafters are 1x6, so I doubt I could get spray foam to work for me. I've focused on other things like rock wool, and other types of ceiling insulation, and replacing windows and doors with modern tech to get the energy efficiency that I need.
You want to kill the chimney effect first. Spray Foam The sill. Then the walls. I put aluminum double bubble across my rafters which were doubled up 2x4s on balloon framing. Then did the same to the walls and tapped all the corners and seams off. I didn't condition the attic. It has 2 windows and a ridge vent. I've Never had a moisture build up in the house. It all went out through the attic or never came in. Cut my heating bill by 80%...
I live in South Florida and I have had to do WDO inspections for home refinance. There has been issues with homeowners Who have put in spray foam insulation and cannot get bank approval.
For the most common reason of it, making it inaccessible to see if there is or was termite damage that's being hidden/ iconcealed by the insulation. It also prevent us from being able to treat the exposed wood throughout the attic in a preventive fashion against wood destroying organisms using profucts like bora-care or premise2.
Very informative. Thanks Matt
Matt when encapsulating an attic you need to purge 30 cfm. So humidity does not build up. The solution could be as simple as a Ecor Pro dehumidifier.
This reminds me of a video you released about 3 years titled "I’m recommending we NOT INSULATE This Old House"
The historical context and designs used on these old english homes is not being taken into consideration when adding insulation. They could even have these issues with normal rockwool or fiberglass insulation if installed in the same way.
Well nuanced vid, Matt. I'm glad I'm subbed.
Another comment regarding moisture control:
It’s my position that you will never be able to completely keep moisture out. Even if you did, I’m convinced the seal would fail over time. A “tight” house is a trap for moisture.
Instead, I focus on what I call “moisture management.” I assume moisture will get in - so I make sure there’s a Way for the moisture to get out. For example, I advocate installing siding with a small gap between the siding and the moisture barrier. That way, any moisture that gets in can drain out. I ensure there’s a clear air path on the underside of the roof, from attic vents to ridge vent.
I put a layer of ridged foam between the decking and spray foam. If the decking needs replaced we should be able to peal the bad decking off without touching the spray foam. Time will tell though
Ventilated antics are tried and true. Much more forgiving than unventilated antics.
Before I watch the rest (I'm only 2 seconds into the interview), Im going to veture a guess that (like everything else HVAC related in GB) they are doing it wrong; Government subsidies caused a bunch of businesses to spring up overnight without proper understanding, training or expertise and a whole lot of salesmanship (backed by government messaging).
Now back to it, let's t see how my prediction holds up.
I concur. We had our city mandate on homeowners to put water pressure regulator. They said that if we do it within two months, we can get reimbursement, but if we don't, later on we will have to foot the bill. They even gave us suggestions which companies to call. After install, it needed to be inspected by the city inspector. I called and guy was send to our house in 2 days. I checked during those days about total cost and the highest price for top tier back then was $95. City stated that they will reimburse up to $850. Notice word "up to". The guy came, did it in 15min and charged us .... yes you guessed it, $850. Then magically city Inspector for which the wait time is usually over a month, showed up 2 hrs after job was done. We both went into crawl space and thank God he came so fast (although I found out later that they scratching each other's backs). The water was dripping and since we always had bucket sitting under crawlspace water shut off valve, I had already about 1 /4 of gallon of water in a bucket. I panicked and told the Inspector that I will call the guy to get his butt back right away to fix the leaking issue and a da... Inspector tells me " don't bother him, it will be ok. In time the dirt and and grease from the surrounding area will plug up the connection and act as seal and stop the leak. I know that guy and he is always doing a great job". That's when my red flag went up. The city inspectors and other officials were directing people to their buddies because there was "free" money flying around. I told his that I don't give a crap since I paid $850 for job that took 15 min and part for $95 (they probably had further discount) and based on travel cost of the company and per Hr labor, should cost on high end even if charging 1 hr labor, no more than $550. I called the guy back. He came back ticked off. This time I watched him like a hawk and it took him less then 7 min to fix it and no leak after that. I was furious because this city reimbursement money didn't come off the tree, it came for property taxes from all of us. People who couldn't afford to pay upfront costs and be home magically waiting during the week day hour for installer, got screwed.
i feel really bad for these homeowners who had no idea about the science with spray foam. the government who pushed this 'fix' should definitely reimburse them for this error. with that said, as i understand it, the lenders not extending mortgages to these homes only if it applies to retrofits without engineering. they are mortgaging homes that have been retrofitted with engineering sign off and new construction with engineering as well. so as long as the ventilation, vapor transport mechanisms, and materials used are accounted for and engineered, there should be no issues.
Unless somehow the engineering failed to take every aspect into consideration.
@@elgringoec as is the case with anything engineered... but within the scope of mortgages, i believe lenders will extend mortgages to engineered retrofits.
I live in NYC and there are a lot of old houses here that got spray foam due to an incentive a few years back. So, I can see it becoming an issue in some areas, because it was a money grab for some of the insulation companies without much consideration for building science.
While properly installed closed cell insulation with no leaks will solve the problems from vapor condensation, It can greatly increase the risks from bulk water from above when the roof fails. Yes, some people replace the roof when a periodic roof inspection indicates that the roof is close to end of life, many people first thought of roof replacement is when the brown stain in the ceiling gets larger and may take a year or more to figure out how to pay for it when they get an estimate of the cost. By that time, it won't just need a few pieces of roof sheathing replaced, it will need much more sheathing which is still glued to the insulation where it hasn't rotted to mulch and roof rafters with it. Won't it be fun to rebuild those trusses. Much of this damage will be done before any water gets through the closed cell foam to leave the brown stain on the ceiling.
Having lived in the UK for over a decade, coming from continental Northern Europe, the type and quality of construction in the UK is shocking. It’s not only the cold climate, it’s the year-round humidity, and that they absolutely weren’t building for it.
Your comment that some house are “under-insulated” made me choke. There are buildings here as recent as 40 years old that have either 2-3 brick thick solid walls, or a 2 brick thick wall with a totally empty cavity in between. No underfloor insulation, no roof insulation, just the expectation of cheap natural gas for all eternity. To the point that the only way to adequately dry out your house is to have heating on 24/7.
The spray foam roof insulation ‘scandal’ is the result of an endemic culture of short-sightedness coming home to roost, not only once (when originally built), but twice (when foam was installed). New requirements here finally got higher air tightness and requirements for mechanical ventilation (ERV/MVHR), but even then the homeowner rarely understands what it’s for, what it does or how it’s supposed to work… much less maintains it properly.
We closed cell spray most of our projects here (Washington DC area). Never had a problem. But we subcontract it out and the installer is really excellent.
Who is the installer?
@@geode232 insealators
Matt, most of the pre 1920 properties in England are slate or clay tile fixed on timber (lumber) battens fixed directly to the top of the rafters with no underlay, roofs then started to include a layer of roofing felt below the battens with this becoming the norm from about 1950. The use of timber sarking boarding above the rafters was generally only used on higher quality/status buildings, it has only become more common on domestic building recently, especially where there is habitable accommodation within the roof space.
Spray foam only really began to be used in England from the 1980's and then generally only for retro fitting, its use mushroomed about 20 years ago when there were government grants available for installing insulation to older properties, this attracted many unscrupulous installers with little building science knowledge to promote it for totally inappropriate situations who then often had very poor inhalation procedures.
yup inhaling foam is bad for you.
Good video, the conclusions are good. You are low balling the humidity in the UK. Depending on time of year and location it can vary between 50% to 90%. Most roof construction is roofing felt on top of the rafters you see in the videos with batten nailed on top of that to hang the tiles from (tiles are nailed as required by building regulations) so not a lot between the cold tile and the inside of the roof space, nothing you would recognise as a deck. The big problem with this sort of work is the government grants for it. Companies will convince people that the the new (funded) thing is good for them and do the work, then get paid by the government irrespective of whether or not the house is suitable for the work or not. This behaviour repeats with each new government initiative to improve the (elderly) housing stock of the country.
I'm in the process of converting my flat ceiling to a vaulted ceiling. I watched how you've used 2in closed cell and then finished with open cell on top of that. I live in NW North Dakota borderline zone 8. Do you recommend using this method for my area?
Thanks Matt! I love your videos!!
I agree with you on "shorts". The viewer has no idea what was left out. Sometimes the exclusion is innocuous. But more often, it's leading you to the conclusion the author wants you to make.
It's easy to manipulate a "short".
It seems like England has a problem with properly selling spray foam.
i.e. "We can do a job with closed cell phone but open cell costs only 1/3 of that." WRONG OFFER, especially in cold and rainy old England....I wonder what the average nighttime humidity is.
Yes, that's the case, manipulation can be the goal. It's like playing a clip where someone says "there are fine people on both sides" and leaving out the part "and I'm not talking about the neo Nazis" so dishonest people can say the person called neo Nazis fine people. Same basic tactic.
I am in Canada... and I removed all spray foam... everything was rotted.
I have douzen of pictures of the mess
I’m not a fan of anything “permanent”. If you can’t disassemble what you assembled, you can’t fix anything.
I agree with you and like your comment. Question: Are you also a bit older? I only say that because I have been a building contractor for about four decades and have seen many products not hold out as represented. A popular product "PEX"warranties 25 years, copper 50 years. 25 years is not very long buried in a wall of your home.
Absolutely correct. I live in an 80+ year old home and have been able to renovate and repair much of it because it’s all accessible ( water damaged fiberglass insulation, insulation in the wrong places, leaking pipes, substandard electrical wiring, etc.). If any of this was inaccessible, we’d be looking at a demolition and rebuild. Radiant heating embedded in concrete? You are putting a lot of trust in something that will be a nightmare to fix if it fails.
@@janking2762 Very true.
@@fsoileau I respectfully disagree with your Plumbing analogy. We don’t know the lifespan of PEX yet. Just because the warranty is set for 25 years doesn’t mean it’s not good for longer. We’ve all seen copper lines that are well over 50 years and are perfectly fine.
I have seen copper lines that were installed touching a dissimilar metal and have corrosion to the point of failure. It comes down to how it is installed same as PEX
I think a lot of the issue is the type of roof that is typically used in the UK. Ceiling tiles directly over purlins without waterproofing barrier, thatched roof, etc.
These roofs leak, and with spray foam applied, keeps the moisture on the wood rafters causing the issues
He went over that man lol
That house looks more like 90-100 years old rather than 40. Roof structures in UK are generally very different to US.
"Under insulated" is an understatement.
Recommended ceiling insulation in UK is 300mm (12"). Normal is fibreglass.
Tiled rooves on tar paper with battens is normal and as you say relatively breathable.
Your homes in the US are very different.
Insulation in the UK is generally very poor to non-existent in many houses, and I don't mean to stereotype, but most people's solution is to just put on a sweater and drink a hot cup of tea.
Thanks Matt.
Great video ! Thank you
Don’t forget a lot of those roofs are slate aswell which is a tad colder in general.
The only problem with spray foam is bad installers. That's why I won't use it, because I don't trust anyone to do it right.
Right mixture, right thickness, right coverage, right temperature, right amount applied in one area at a time, right dehumidiication system, right home to begin with.
Most installers don't underatand half of the required variables to create a safe install.
Agreed. Installer quality seems like a major variable. However, a procedure that is easy to do wrong, and when done wrong can lead to catastrophic failure, doesn't sound like a good choice.
Ooooof man, Ireland is not part of the UK.
Northern Ireland is, but given that he mentioned Wales he's probably aware of that and may have simple misspoken.
@ could also assume being American that he simply does not understand the difference between wales, Scotland or Ireland 😂
No one cares,
There are like 5 people that live in Wales.
11:00 Another thing that you don't mention and is relevant is the fact that the UK has a rather humid climate year round. They can basically expect some rain every other day.
Matt this is typical of UK government btw, drive diesel (diesel good, petrol bad), a week later, diesel bad put tax up on it.
Open or closed is bad for roofs. Issue is that if the roof has a leak, its make be impossible or very difficult to locate it. Water will pool & rot the roof. Either batts or cut peices of rigid foam panels should be used instead. You can always remove them for inspector or roof repair.
I suspect in the next 3 to 7 years there are going to be a lot of US homes that need roof replacement caused by spray foam.
In the UK it rains often (think northwest coast of USA) the humidity is high there.
I find it interesting that in the UK lenders obviously do some sort of inspection. I have bought and refinanced a relative LOT of real estate here in the US, in several states over the past 25 years and not once EVER has a lender done that. They get an appraisal report, but that says nothing at all about the specific methods of construction, only an opinion of the value. And my home in Maine is more than 200 years old in part (no spray foam though).
Matt, you are also missing a weird thing about UK homes and that is that they have water tanks in their attic. They have very low water pressure because of old pipes in the ground so they have to have water tanks in the attic to supply the house. I am sure that causes even more mosture in the attic that here in the USA.
Definitely that would add another layer of humidity which would exacerbate the problem
Don't be silly. It's just a closed tank with a breather pipe to the attic or through the roof. That is very very little evaporation.
My 1970s home has mains pressure water (about 3 bar) - hot and cold, no gravity feed.
Old central heating boiler had an expansion tank in the loft but that was removed and it's now a pressurised system.
That's a lot more normal than tanks in the loft these days.
I have an old (1890s) home in Michigan and would love a video about insulating the attic. Was going to go with Rockwool for the breathability. I'm under the impression that any spray foam (closed or open) would potentially have issues with moisture. You seem to elude to closed cell, done correctly, wouldn't.
To me a mineral wool seems pretty fool proof, provided I can get my desired R-value in the current space of my rafters. Plus the noise reduction and pest deterrent seem like positive secondary benefits
One assumption I see being made here is that if the outside temperature is 30 degrees the roof will also be the same temperature. This will be approximately correct at night if there is cloud cover blocking the infrared radiated into space by the roof. If there is no cloud cover the roof will be significantly colder than the outside air temperature because the roof is radiating infrared energy into space. Over time the cold roof will cool the air temperature. This will of coarse be affected by any heat leaking from the building envelope into the attic.
In the U.S. lenders and insurance companies can calculate their potential losses from spray foam. Many homes will have no problems and a small number will require huge amount of remediation. The larger risk is the current abysmal quality of brand new production homes on a massive scale: dangerous framing, cardboard sheathing, window failures, substandard electrical, plumbing, roofs, foundation preparation, etc. These problems have the potential for billions of dollars in losses.
Matt, Robin Clevett is the one to meet.
Agreed
Show us THE BURN TEST on spray foam.
Thing is we have a lot of insulation companies starting to do this same thing over here in 40-70yo houses, or recommending it. People just need to understand the science of moving the envelope from the ceiling to the roof deck and we need smart people managing that instead of just saying "Spray it!".
The issue is spray foam is being used to cover up structural issues and mold. It can also trap moisture. Nearly all homes in Europe are 1970's or earlier built.
Spray foam is highly toxic. Burns like gasoline. If it separates you’re gonna have water mold issues. Skilled trades are lacking in skills & conscientiousness these days. Seems like a terrible product. Unless it’s perfectly installed and you like breathing chemicals
Insurance companies are pushing hard to make people homeless and to grab properties and close down residential areas; Florida, Hawaii, Nc, Tn.
It might be okay in dry places but for the Norht East it seems terrible. It’s the same concept as EiFis that foam fiberglass nonsense that rotted houses
Just cause it works doesn’t mean a house shouldn’t breathe. Fuel costs are not everything. If you wanted the best house ever it would be made of concrete on all surfaces but yet we build with wood. Let the house breath and use mineral wool.
I imagine any leak in the roof traps moisture and causes woodrot.
open cell allows the water to pass straight through.
Matt absolutely right
Love your content😅
Agreed shouldn’t be problem in US , but insurance companies are looking for reasons to not insure properties and it could be a good one
Contractors used to swear by open cell, so you can find roof leaks.
It’s about time. Spray foam is the devil.
No it's not. too many installers are idiots.
2:35 that house is a 1970s style house in the uk built from late 60’s until mid 80’s
Thanks!
From my research you can't just "retrofit" spray foam onto a roof attic as you need to account for the roof structure and load. My trusses my be able to support the extra weight but with air flow would be a factor so it would need to be re-engineered to account for that.
That might be one reason they went with OCF it's light, and there's not much snow load there so OCF ought to be within the capabilities of any reasonably framed roof. CCF is several times denser.
A building with a top hat (uninsulated roofline) is insurance. Turn or treat your attic as conditioned space with foam and the underlayment roof barrier had better be PERFECT or your foam will hide a leak until it's too late. I do not understand why that risk is taken.
The issue is that the foam is functionally treated as if it's also a sealer no matter where it goes. There have been decades of black, soggy fiberglass batts that were treated the same way, with the same results. At least with batts you can yank it out in SECONDS if necessary.
Please think of repairability, not just quick efficiency in the moment when everything is still shiny and new.
Matt, we are thinking of doing open cell spray foam in our conditioned attic assembly. We live in Oklahoma. We couldn’t afford rigid foam on the deck. Would you recommend a taped smart vapor retarder at the bottom of the joists after the foam?
Ask Joe L at BSC , I trust him more than anyone !
Building science Corp …..
This makes me a little nervous as we are building a barndo with wood frame and steel siding and roof and were thinking that closed cell foam is really the only way to combat the condensation on the steel. Is there a better way to do it? And should we put tyvek between the steel and the wood frame, or just apply the foam straight to the steel?
My issue with spray foam is the “what if” factor. Yes, you can engineer a solution that works if everything is done right and goes right for decades.
But what if something is done slightly wrong? What if something fails at some point 20 years later?
Complex systems need to handle non ideal conditions to be durable. Spray foam, as great as it is when done right leaves you 0 margin of error. You’re setting yourself up for possible (likely) disaster at some point in the future. People can choose if that’s worth it to them. I don’t think it is for me. Especially when you can build assemblies that perform 80-90% as well, cost less and have the ability to withstand non-ideal conditions.
AND SCOTLAND!!!!!!!!!!!!!!!
The uk is probably one of the worst climates to use open cell spray foam on the roof line. It's fairly cold and very wet, basically all the time
Probably needed to make it a conditioned attic or at least install a dehumidifier. But also, proper installation of the foam and proper foam would have been the best foundation.
Please dont use Chat GPT as a source, it is consistently wrong.
A building, any building, has to be designed as a whole. Modifying it willy-nilly is asking for trouble. Taking the advice of a bunch of UK politicians is always a bad idea
2:45 “UK is Wales, Ireland…”
Northern Ireland
Lenders also might not lend on wood(timber) frame homes. Most UK homes don't have much if any insulation. It is only common in newer built homes.
Makes perfect sense. 👍
Skip sheeting a few inch gap? Now with a shake roof which is much more likely in the UK. Heck could the thatch
I can't imagine a good scenario for me to use spray foam. Whatever benefit it may have in insulating properties is less than my desire to inspect, maintain, change, etc.
Cliff Notes version: UK, you're doing spray foam wrong.
😁
Seems the problem is installing Any insulation in the rafters without either reserving a soffit vent-to-ridge vent air channel above for drying or completely sealing the lower surface of the insulated layer from vapor transmission (or both). Rockwool in the rafters without these measures taken will still allow warm moisture thru to the roof sheathing where it will condense on the underside. And additionally as someone else mentioned a dehumidifier should probably be installed in these sealed attics as well anyways.
Any thing that one has to wear a respiratory to install can't be good at any time
I'm building a home and they said we'll spray foam the jost cell, lol I had asked to not to spray foam them I'll rockwool them myself, I plan to Valkum caulk the joints and pack it with rockwool
Gotta love insulation. And with the IRC 2021 codes, now they're requiring R-60 in the roof, which I am sure is going to have a lot of builder's turning to foam, since the R values per inch are higher than batt. For years, R-38 worked just fine, then they went to R-49 for a couple years, and now ... well now, I have to wonder who is in who's pocket selling insulation? R-60 might be required in Alaska, but Virginia?
Don’t forget that you are not required to use foam. You can easily get to R 60 with a very cheap blown fiberglass or cellulose as long as you pay attention to air ceiling between the house and the attic, and definitely don’t have any ductwork up there.
Working on this now in Massachusetts, we are using 4 inches of reclaimed eps foam board on the roof with rockwool batt insulation. Price is comparable with closed cell spray foam even with the increased sheathing costs
Not sure Matt is appreciating just how many older homes here are getting the attic foamed treatment. Its quite a few in areas without a lot of new development. Foamed roofs with complicated rooflines prone to leakage is going to be a pretty big problem. Also need to remind that sometimes the Insurance co's don't care that your roof was foamed properly. They are going to lump you in with everyone with a foamed roof.
I wonder if stupidity, ignorance, and carelessness was as common in the past as it is now? Because it seems like that every other person in a trade or service is an incompetent huckster out for money at their customer's expense. My parents were constantly victimized by idiots and frauds claiming they could build/repair/refurbish/clean etc...
They are uneducated trump humpers and I f’n despise these clowns. Just super trash humans with no regard for others.
No air gap between the foam and the roof.
Would be your opinion on your take on xps and eps board.
No mention of dehumidification. How many of these UK houses had a dehumidifier?
What happens to roof sheathing when the roof (shingles, metal, etc ) leak and there is spray foam on the inside?
Ignorance drives so much in this world.
No one who's ever had to fix a leak on the other side of some polyurethane foam wants to do it again.
If it cant dry, its gonna die. In the event water does get in, the foam will never let the framing dry. Ive seen this happen to sprayfoam and fiberglass and plastic vapor barrier. From what i gathered The sprayfoam case was caused by not caulking the windows. And the other was an old barn where the exposed fasteners were beyond their lifespan in combination with being overgrown with trees and shrubs. Read: lack of maintenance. Id even say maintenance in both cases. Whereas the customer who had his barn foamed never checked or recaulked his windows. Love what you are doing Matt. Less the foam and engineered lumber, i dont enjoy breathing in glue dust.
Also, foam makes it a pain in the ass to do renovations or repairs. And you can't put it back in, you have to pay someone to respray
awesome bro!
A guy I know works for Aqua Barrier. He showed me pictures of a crawlspace under a home that had been sprayed with foam (open or closed I don't know. Assuming open). The house had to be demolished because the sub structure had all rotted out. I'd love to use foam in future projects but can't figure out what information to trust.
This is a great video