What's the fuss about spray foam?
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- čas přidán 29. 08. 2023
- In this video we look at spray foam insulation sprayed into loft spaces. Is is necessary, is it a good idea? We look at five main areas:
1. Thermal
2. Fire Risk
3. Condensation
4. Mortgages and Home Insurance
5. Costs
As a Rooftiler for 45 years I have to agree with everything you have said. Good video no messing around and straight to the point. Well done.
The question that springs to my mind is how do you take it out, that would be a good video topic, how to effectively remove spray foam
I will say you have some good point. That being said, we have spray foam on the roof decking here in Texas. Works great, however once spray foam is used and the attic is sealed it must be considered conditioned space 100%. No venting and lack of conditioning will for sure cause many bad things to happen. We don't have any blown in or bat insulation at all in the attic. Here where it regularly gets into the mid 40C temp range outside it works extremely well. The hottest it gets in the attic is about 29C at the top of the peak. Our peaks in the attic are about 7 meters from the ceiling, we have 12/12 and 18/12 pitch roofs here as well, so a huge amount of volume in the attic. We are going on 14 years since the house was built and have had a roof replacement a few years ago, as we get lots of large hail here, so our roofs are replaced regularly here, however with a 12 year run on the old roof, except for the hail damage it was in great shape, both the shingles and decking, no cracking or any signs of stress. I made sure that our roofers took off all the underlayment as well, to inspect all the decking for any signs of damage both physical and from water as we use wafer/chip board for decking here. With the sprayfoam there is no way to inspect it from below.
I would not have it put in after the house was built for sure, as our attic was designed from the start for sprayfoam. In our attic over the garage that wasn't spray foamed and is just vented, it can reach 60C+ in the summer and will melt plastic, so by far the spray foam is working great at least here when the roof was built specifically for it. We don't use vapor barrier here as its not needed because of the hot climate, although it can get to -20C here, but typically for a short time. All of the exterior walls are sprayfoamed and all interior walls are insulated with bat insulation. The house is just under 700 M2 in size and is a single story brick and stone facade. They also put in weep holes in every brick on the first course to ventilation between the brick and the exterior house wrap as water can build up in there from rain soaking the brick.
The house across the street from ours got hit by lightning this spring and it was quite the fireball off the roof and large hole in the peak of the roof. Their spray foam didn't ignite, as they had burn/scorch marks all over anything metal in the attic, I even checked our attic just incase as I knew it was close, but not that close until I saw my security camera footage of the explosion of the bolt of lightning and the large corona ball falling off the roof.
But like I said I would for sure have a vented attic in the wetter climate like you guys have there. Keep up the good work! 👍🤠
Good points, I too live in the South (Louisiana) and have spray foam. One thing that was left out was that the HVAC equipment is now in a conditioned space, which reduces the workload of the equipment. I do have a whole house dehumidifier which does help with humidity and any possible issue with too much moisture in the attic. I have a 3800ft2 condition space home with a 12/12 pitch roof (on most) and I only have 5 total tons of AC (2 stage) for the entire house. no issues trying to cool. My attic stay around 5 deg F difference from my living space as well. Like you said , the attic must be non-vent to make this work properly.
He mentioned the roof rot if moisture is to get through the deck. most people here use Open Cell foam for the attic, which would allow you to see if the roof is leaking as the water would seep through. As well I use Zip System Sheathing on the roof (and entire house) to mitigate the possibility for roof leaks.
There is a lot of building science to offset the issues he mentions in the video, and if work is done right, all these issues can be avoided.
@@chrisarnone7896 Yes, for sure the issue is the retrofitting of the much older homes. I wouldn't have done spray foam on existing house, but being a new build it was fine. Yes I have open cell in the attic as well and on the sidewalls. However I know of many people that use closed cell at least on all the walls, as the closed is actually considered part of the physical structure of the house. It can be super impressive to see the blower door test on some of the newer houses where the actual builders of the house take their time to seal all exterior holes and use special techniques specifically for foam sealing for the wall and roof penetrations. We have to have high efficiency HVAC and air exchangers as well to bring in outside air for combustion on the furnaces as well as fresh air for the house. Its amazing how quickly the air can saturate with CO2. I have a number of CO2 and other air quality measurement systems in the house in our home automation and if you don't run the air exchangers, the CO2 levels can rise pretty quickly. Even with the outside air being filtered, when the air quality is bad outside with high particulate levels, we let the home automation figure out the when to run them, so not to pull in more bad quality air, but keep the interior levels within reason. We also have our fire sprinklers in the house interfaced into the home automation, so that if there ever is a fire, we stop spreading smoke around the house and stop fresh air from coming in. Obviously depending on the extent of fire/damage it may not work, but at least we try to think of the scenarios to control things logically at least. 🤠👍
A really good summary of the issues surrounding spray foam. Well done!
Thank you.
Thank you for the excellent video.
This addresses spray foam exactly as we should be approaching the material, namely as building pathology surveyors.
There is no wiffle waffle about BRE, agrement certificates, installer surveys etc.
It deals with thermal insulation, and fire that has not been discussed before.
We just have to be confident in what we do, and if we even just ignored the name of spray foam, and think of it as any material placed between the rafters, we can take on board the correct methodology of thinking.
Thank you for your kind comments Neil
I retired from surveying 10 years ago and when the spray foam application were being promoted we persuaded many clients from applying this to the underside of roof structures. I think there will be many surveyors defending negligence claims over not addressing this problem
very informative! thank you!
Thank you Sir, that is very very interesting. I've always been suspicious of this since I first saw it done about 35 years ago, same with retro-fit cavity wall insulation (of the injection kind).
Please consider amplifying your audio by a considerable margin (say 200%) in your video editor software. Kind regards.
You have confirmed what I already thought about spray foam. What is the point of heating all that space above a ceiling unless you use it as a room?
Please note that the surveyor is discussing UK designed properties, and may not be relevant to properties outside the UK. That being said, excellent summary of the facts surrounding spray foam loft insulation. Run away from it!!
We attended the Ideal Home show in London a few years ago where there was a loft spray foam stand, and our house being a 100 years old and having no roof felt made us look at the spray foam option. We were giving an impressive sales pitch but In the end we decided against it. In hindsight it was probably one of the best decisions we ever made.
You may have dodged a bullet there!
That was very informative and well presented, despite the many eh's and ums,.
Sadly I've had mine done which creates a rather snug loft which is great for storage but crap for a healthy roof and selling or remortaging my house. I dare say we'll get it removed now. Thanks again for posting this.
Wont be great for storage if the dew point is met or close often.
I think we were all better off with the insulation available before the Spray Jockeys (you notice how they've all popped up like weeds?), if for no other reason than the old stuff was easier to remove. One of the biggest problems I have is the guys do not do prep before. Foam is paint, and any paint job is ruined by bad prep.
Useful. I'll not have. mine done then. I had a couple of firms that wanted to do ours, but as they started out on the 'it'll be free' line and regressed on interrogation to 'it'll be expensive' I advised them to sling their hooks. Incidentally are there any non combustible insulations?
Sounds like you have dodged a bullet there! Well done.
Drastically injecting foam into the cavity-walls would stop the property breathing , resulting in drastic saturating condensation build-up in the inner walls of the property.
Foam is an air barrier material and doesn't let moisture into or through the product, thus eliminating condensation possibilities. House needs ventilation and you need to breath fresh air. Open windows is an option with any insulation
Very good critique of spray foam. Is the statement at about 7 minutes correct that mineral wool and Rockwool can catch fire?
Hi, yes it is. We’ve renovated a house and burnt loads on bonfires. Also, our main work is insurance claims, including fires and it will most definitely burn. Thank you for watching and commenting.
Rock wool is made of rocks. Rocks don’t burn. Rockwool will melt at an extremely high temperature, but it will not burn.
Pretty sure mineral wool can't itself burn?
I believe this is quite popular in the United States. In terms of warmer climates is there any argument that condensation will be less likely and that insulating between the rafters will keep more of the intense heat out of the loft space?
I think you are right and it is more common in the states, but they have issues too. Condensation happens interstitially so is a bigger issue.
@@westonesurveyors8139appreciate the reply, just discovered your channel and enjoying the insight into surveying and pitfalls of supposed solutions like this.
I’ve been looking at a house which has had foam insulation installed for around 18 months now to a 23 year old bungalow (pressure sold to an elderly person). The property is now on the market for £18000 less than an independent valuation due to this. In your experience, providing the foam was removed straight away how high are the chances of wood rot etc?
Hi, thank you for your comment. It’s impossible to say for sure without seeing the installation and the roof structure, but if it’s only 18 months old, chances of rot should be fairly low.
@@westonesurveyors8139 Im removing my instaltion for a new roof on our newly purchased house. The insulation was installed we think 10 years ago. There is rot to the beams (timber from wall to peak of roof) in a few spots and a lot of the rafters (the sideways lats if I've got the term corect). I'd estimate (im not an expert though) if it was there for another 10 there would be major problems in the roof if not before then. For context my roof is 80-90 years old already, the spray foam is open cell insulation, sprayed directly onto the tiles but not completely covering all the inside off the beams. My roofer does mainly roofs in the area (estate where there are loads of the same houses all built at the same time) and he says the rafters are the worst hes seen in a while for rot.
Would you recommend not using spray foam in any instance? I am thinking of insulating a shipping container. The tiny home people all say put spray foam on the interior of the container and it acts as a vapor barrier. Is this false?
Containers will be different as the structure is not moisture vapour permeable. Rust may be an issue if interstitial condensation occurs.
Think this may be a possibility as I understand they apply closed cell spray foam thermal insulation to the hulls of
boats and barges. Do seek professional advice however and obtain a condensation risk assessment.
As a Building Surveyor myself I found this very interesting and a good summary of the potential problems of spray foam insulation. At the end of the day I see no benefits whatsoever of using foam insulation and steer people away from this. As you point out the easiest way to improve thermal insulation in a cold pitched roof structure is at ceiling level - even if this means using a high performance material such as Celotex to get the best results. If people really want a warm pitched roof then sheet insulation combined with a vapour control layer below and a ventilated gap (or a breathable sarking) above is preferred as it is cheaper, reliable and easy to remove - which is why lofts spaces are normally converted using this method. The cost of removing spray foam, especially the adhesive type, is high and should also therefore be a deterring consideration.
Insulxtract removed mine
Why is this stuff legal
Unfortunately we have an unregulated building industry in the UK, so while most firms are good, the will always be ones that will do anything for a quick buck. It also doesn’t help when the PCA and RICS sit on the fence and do not provide good guidance.
My dad had icynene foam put in the loft about 4 years ago while on a bi polar high and eco guilt should i call a surveyor and how long does foam take to cause trouble. Thanks, great video.@@westonesurveyors8139