…… Maybe: Help- Advice needed on spray on insulation.

[tiredude]

So the gentleman who fixes all my autos had spray foam insulation sprayed into his metal building three years ago. He swears by it. I am thinking about having the process done to my attic in an attempt to make my home a bit more efficient. Does anyone here have experience with this stuff? If it makes sense I will do it. I know nothing on the subject. Thanks.

 

[hiwall]

I too am curious of any replies.
I have heard it is expensive but that could just be a rumor from a long time ago.

 

[Millwright]

Doing a barndominium build out in a metal frame building, it does hold temps well.

I've heard that it holds moisture in wood framing and causes rot.

 

[tiredude]

it was pricey 10 years ago..... but hopefully it has become more mainstream now...... I dont have a clue......

I will talk to some local suppliers on Monday but thought I would test what the pond thought.....

 

[tiredude]

Doing a barndominium build out in a metal frame building, it does hold temps well.

I've heard that it holds moisture in wood framing and causes rot.

uhhhh..... thanks bud......thats a deal killer!

 

[Dennis Olson]

Please remember to use the help prefix when asking for assistance.

Changed

 

[Millwright]

uhhhh..... thanks bud......thats a deal killer!

I'd look into it some more.

That's just what I've heard.

Probably be a lot cheeper to get an insulation blower from big box and just pump a gob of fiberglass into the attic,

A friend at the coast sprayed his attic with some kind of thermal barrier paint.

Said it made a huge difference.

 

[ktrapper]

Doing a barndominium build out in a metal frame building, it does hold temps well.

I've heard that it holds moisture in wood framing and causes rot.

Yes it does hold moisture in wood and cause rot. We done a lot of repairs where this was the case rotting out rafters and walls. Told to me by a fireman is also has a chemical that degrades the insulation on house wiring after a long time. It’s nothing immediate. I know for a fact it gets water logged. Even the closed cell stuff does eventually. I have seen it.
Sprayed on the inside of a steel building should be fine. It’s open to air.
I am just speaking from my hands on experience in Alaska construction work.

 

[West]

I like it.

BUT, you still gotta have ventilation!

Excellent idea and it works great. BUT YOU GOT TO HAVE VENTILATION.

See, it's like this...the tighter the envelope the more efficient. However the tighter the envelope, the more it can make you sick! Or rot wood!

So the happy balance.... build and foam it tight, but also install fresh air ventilation. Like windows you can and should keep cracked open.

Or install a HRV...

Heat Recovery Ventilation (HRV): Definition, Advantages & Installation | Linquip

According to international reports worldwide, 15-25% of heat loss from buildings is made happen by air leaking out of the building. Heat Recovery Ventilation (HRV) proposes a method to bring fresh air into your home without allowing the heat runaway.

www.linquip.com

But this requires a competent HVAC guy and duct work and you to keep it maintenance!

Best of luck!

ETA.. also still ventilate the attic still. Or crawl spaces. Ventilation is always plus.

 

[Kathy in FL]

So the gentleman who fixes all my autos had spray foam insulation sprayed into his metal building three years ago. He swears by it. I am thinking about having the process done to my attic in an attempt to make my home a bit more efficient. Does anyone here have experience with this stuff? If it makes sense I will do it. I know nothing on the subject. Thanks.

I have heard from several people that the stuff rusts/is hard on the screws/bolts of steel buildings.

 

[kenny1659]

We had the underneath of our home sprayed 6-7 years ago and it made a big difference. It cut drafts and sealed all the cracks and holes where bugs and mice could get in. Had wife's sewing building (8X14) sprayed walls and ceiling, 6k btu ac cools quite well even when it is 100+ degrees outside.

 

[West]

We had the underneath of our home sprayed 6-7 years ago and it made a big difference. It cut drafts and sealed all the cracks and holes where bugs and mice could get in. Had wife's sewing building (8X14) sprayed walls and ceiling, 6k btu ac cools quite well even when it is 100+ degrees outside.

But be aware of mold and what not. Just saying ....... ventilation is the cure for many ills.

 

[Kathy in FL]

Pricing. We had our new 40x40 steel barn reviewed for the stuff. $14,000 was the minimum it was going to cost.

 

[tiredude]

I have heard from several people that the stuff rusts/is hard on the screws/bolts of steel buildings.

thanks Kathy...... this will be all wood but Millwright says it has been known to cause rot..... my roof is extremely heavy..... cant take a chance

Please remember to use the help prefix when asking for assistance.

Changed

Thats why I labelled it the way I did..... I didn't know which was proper. It is discussion on a project......(maybe help)
but thanks for the help anniewey

 

[Texican]

In our addition we had the walls and attic sprayed with 6" of foam. Even this summer with the oppressive heat was not a problem. Wood rot will only occur if water gets to the wood. The metal roof was installed over a layer of waterproof membrane. The exterior walls have a layer of waterproof membrane under the siding. Cost was $2,700 for 94' of 6" walls and roof over 40'X50' floor area.

There should not be a problem using foam insulation if applied correctly.

Texican....

Spray Foam Insulation Problems – Does it Cause Wood Rot?​

Spray Foam Insulation Problems - Does it Cause Wood Rot? - Sunlight Contractors

Open-cell spray foam not only insulates to improve temperature consistency but it also seals cracks that allow air leaks. But does it cause roof rot?

www.sunlightcontractors.com

Well, will it? It’s a reasonable question to ask, considering that some homes with open-cell spray foam insulation installed on the underside of the OSB roof sheathing have reported moisture problems.

There’s also a pretty reasonable answer to will spray foam will rot your roof:

No spray foam will not rot your roof. But water can.

Open-cell spray foam is breathable. It allows air to flow through it. It also allows any moisture to pass through it. This helps ensure that if water does seep beneath your shingles, it will not sit between the spray foam and roof, creating rot. Open-cell spray foam is spongy and when water comes in contact with it, the water will find a way to pass through it.

Open-cell spray foam not only insulates to improve temperature consistency, but it also seals cracks and crevices that allow air to leak into and out of your home. This can be especially helpful in attic encapsulation, where high temperatures can force hot air through gaps around joints, air ducts, and light fixtures.

Building science experts say that one of the following is the likely culprit when an open-cell spray-foamed home experience roof rot:

• The installer didn’t know what he was doing. He failed to achieve airtight application of the foam, resulting in air leaks. Since air carries moisture (uh-huh, water again), which can lead to mold and rot.
• The installer took shortcuts. Like plugging rafter bays with plastic film so foam doesn’t leak out of soffits during application. This prevents foam from sealing wiring and plumbing penetrations, which allows humid (yep — think water) air to collect and condense in the soffits.

It is important to hire an experienced insulation company, who is familiar with blown-in cellulose insulation to avoid any issues down the road.

Spray foam insulation is extremely popular because of its superior R value. The installation of spray foam insulation, whether on the roof of a commercial building or in your home, requires precision, demonstrated expertise, and a commitment to quality application. Most spray foam contractors ARE NEITHER licensed by the Louisiana State Licensing Board for Contractors nor certified by the Spray Polyurethane Foam Alliance. However, Corey Yates of Sunlight Contractors has completed arduous training and testing, earning SPFA’s highest certification for spray foam installers.

Proper installation of spray foam insulation is the answer to:

“will spray foam rot my roof”?

 

[tnhillbilly]

Not a good application for an attic. A foot of blown cellulose fiber done correctly is your best bet. Don't blow in fiberglass.

 

[West]

Not a good application for an attic. A foot of blown cellulose fiber done correctly is your best bet. Don't blow in fiberglass.

I AGREE with you, But If your duct work is in the attic, insulate the roof decking and trusses.

Huge advantage. But you still need ventilation!

 

[oleglass]

After our house fire several years ago(2017) we rebuilt a new house completely and moved in January of 2019.
Had spray foam in all outside walls, but the roofer contractor really stressed not spraying the rafters and decking.
Fast forward to spring of 2022, wife saw a dark spot over in the corner of the kitchen cabinets.
I go look in the attic, find a wet spot on the blown insulation over the kitchen. Had 10 inches of blown insulation, the water had finally soaked through the insulation and stained the ceiling in the kitchen.
This was where the vent-a-hood exited the roof.
Called the contractor and he came and sealed the leak, did not charge any fee. No leaks since.

So, based on my experience, I would not spray foam the decking and rafters.

 

[Squid]

Spray foam comes in many types. With spray foam you get insulation and for close cell a water and vapor barrier. The problem is if you have water on one side where does it go. Also the application may need some time to clear the airborne chemicals released during the chemical reaction.

Also some cheaper versions used by shady business is nothing but powder and water.

As with anything look for a high quality contractor with a long history in the business who looks at not only the sale but is the use appropriate for the physical application wrt to water wtc.

 

[Jeff Allen]

We built new office in pole barn 5 years ago.
$12,000 in insulation. 1300sq ft.

All foam except attic.

Attic was 36” of blown insulation.

Place heats and cools effortlessly…heat/cool bills are like $40 a month and it’s 68 in summer, 75 in winter…

J

 

[kenny1659]

But be aware of mold and what not. Just saying ....... ventilation is the cure for many ills.

Plenty of ventilation under the house we used close cell under there.

 

[Creedmoor]

Thing that would bother me is that it’s difficult, if not impossible, to undo, or make repairs under wherever it’s been sprayed. I’m assuming this is the commercial version of the spray can “Great Stuff”.

 

[Illini Warrior]

I looked into foam insulation for my cathedral ceiling in the master bedroom - the $$$$ was ridiculous considering the simplicity of the install >> new & reject RV/mobile home insulation is readily available in NW IN - 2" is R value equal to 6" of regular pink batt Owens-Corning - went with 4" and left a 1 1/2" vent channel against the underside >>> takes a week for an inch of snow to melt off ....

 

[shane]

I’ve had professionally done, and done on my own, a number of closed cell projects to good effect.

I like working with the stuff, both big jobs and smaller filling & sealing every nook & cranny.

Component prices have gone up a lot and probably will more, so get at it sooner better than later, if needed.

Also, anything beyond 3” thick is usually off into diminishing returns range and likely wasteful.

Panic Early, Beat the Rush!
- Shane

 

[mechanic 217]

I looked into using it on the new house but the cost was 3-4 times more than fiberglass batts so we passed, current practice in this area, is to spray only 1-2 inches of foam to create a draft barrier then finish with batts.

 

[poppy]

Doing a barndominium build out in a metal frame building, it does hold temps well.

I've heard that it holds moisture in wood framing and causes rot.

It is also a noted obstacle on termite inspection reports because termites can tunnel up behind it without being seen. I've seen it in 2 pole barns and 1 house that built on a room and had it sprayed in the crawlspace with foam insulation.

 

[Delta]

I'm grateful for this post and comments. Seems that " the way to do this" is to spray the underside of the roof. Otherwise one ends up with all the wiring encased in foam and unreachable. They do vacuum out all the blow-in insulation. I like that the foam seals the cracks, etc. What bothers me is that they block off all the vents--they basically turn the attic into another room of the house. I'd sure hire an experienced contractor. And I'm still after opinion.

 

[tm1439m]

I am currently building two homes for my son and my families, and a larger 50'x60' studio.

I have been around and around about how to insulate for maximum R value but I don't want to create a future issue. Moisture being my main concern. You gotta give moisture a way out or it will rot wood. Period.

Spray foam is an excellent choice until its not. What I mean by that is that if your roof system does not fail and if everything is done correctly and perfectly constructed then it will likely be the best choice. However its not a perfect world. Things can and often do go wrong. Then there is the thermal loss at each rafter that I will address later.

If water or even condensation gets into the roof area as in the rafters and wood 4x8' sheets on your roof it can and will likely be a big problem eventually. Water rot.

You have a roofing material covering your home that blocks the flow of water/moisture on top of the roof framing that you are trying to both insulate and protect. . Then you add spray foam to the underside. At the very least that spray foam will greatly slow the drying of the wooden roof framing materials you were trying to insulate and protect.

I think you can probably see where I am going with this. It is never a good idea to trap a moisture sensitive material between two materials that block moisture/water flow. Where will that moisture go? In other words if water or even just moisture get to the wooden framing members of your roof it will rot.

I have seen roofs where the wood rotted and it was not even spray foamed on the bottom. There was plenty of open wood for the roof to dry on the underside but the attic had little to no ventilation so the wood just sat there wet and rotted.

My solution which requires a bit more effort and I have not even began to asses what it will cost is to install a ZIP system roof by Huber. It is basically a water repelling material added to the surface of the plywood on your roof. Then on top of that plywood you add layers of foam board (4'x8') on top of your roof. Then in my case I plan to have a metal roof so I will cover the entire roof with foam boards. Tape all seems. Then screw 2"x4" lumber with long screw through the foam into the rafters vertically. Then add a second layer perpendicular to the first layer of 2"x4"'s across the roof. Then I will lay my metal roof over that top layer of 2"x4"'s. That metal roof will have ventilation under it between the two layers of 2"x4"'s. The attic will be sealed up tight .

If water does get under the metal roof it should run down those foam boards and out the boxing vents. If it gets through the foam (not likely) then the ZIP plywood should shed the water/moisture.

Nothing is full proof but this is darn close in my opinion.

One huge advantage in this method is you have now insulated your rafters as well. No heat will reach any of your roofing members that is exposed within the envelope of your attic. With spray foam on the underside of the roof you have a thermal loss at every single rafter as it touches the roof plywood and transfers a large portion of that heat to your attic. Wood is a very poor insulator in comparison to the insulation you add generally between framing members.

Also with my foam board over roof plywood method if any moisture manages to get to your roof framing or plywood members it will be exposed to the air within the attic allowing it to dry provided you have a dry attic. In addition you will be able to physically see any areas that are getting wet and address the problem accordingly.

With my method( ETA: its not "my method" but rather I was referring to it being the method I am suggesting) here you have a much greater overall R value than your standard spray foamed attic. You loose heat or air at ever single rafter with spray foam that adds up to be a big number.Its a no brainer to me.

 

[20Gauge]

All I can do is give you my experience with closed cell spary foam insulation......

1) Never had a leak
2) I had the wall and roof done, so I have a full envelope enclosing the house.
3) It was done by professionals 18 years ago whom are still in business and are well respected
4) It was cost effective at the time. Cheaper than normal insulation
5) My power bill for a 2700 ft sq home with it set at 69 during the summer and 70 during the winter average $125
6) I did put those breathing slats in before the spray insulation, was told it was not needed, but 3 years later it was. So I guessed correctly when installing.

I have no concerns what so ever about what was done then.

Would I do it again?

Depends upon where I live.

Currently SE GA it works. I can not tell you for a higher humidity environment or cold one, but we are wet and good to go.

after some thought, the one thing to note, our house is sealed really well.... I mean lock a fridge..... that can be bad, but we do open the doors to air things out ........HVAC is required....

 

[Profit of Doom]

It allows air to flow through it

but it also seals cracks and crevices that allow air to leak into and out of your home. T

Make up your mind.