Spray foam insulation

[joxafa]

Does anyone have it in their attic? I've been told it's great on the electric bill. Also been told it causes mold and moisture problems. One ac guy told me not to use it because the ac unit wouldn't run efficiently. Another told me he's never had a problem. I'm not sure which way to go. Thanks

 

[100percent]

Tagging

 

[displacedtexan]

I have open cell in my shop. I love it.

Not the same situation, but throwing it out there.

 

[grfox92]

You don't spray foam attics. You loose fill blow in with Celluslose or even better and not crazy expensive is wool blown in.

Spray foam walls and loose fill in the attic. FWIW I build custom homes for a living.

Edit: I'm not saying you can't spray foam your attic, it's just not something I've ever seen done. The cost wouldn't justify it. You don't live in your attic and unless your really dead set on using the entire thing for storage, blown in loose fill would be way less than half the coast of foam

Sent from my SM-G990U using Tapatalk

 

[goodgrouper]

New construction or existing? Blow in is so cheap you can just addd more to what you already have and gain efficiency. The mold problems come when you don’t have adequate ventilation. We do spray lids in applications where there’s no way to ventilate.

 

[Sled]

You got good advice here. Fwiw, I wouldn't put spray foam in the attic or anywhere moisture could be present.

 

[Broomd]

I have open-cell Icynene sprayed in my Idaho home and can practically heat this place with a candle.
No attic, we have a loft. As was said, blown-in for attic, 'expanding' for everything else.

Best build decision I ever made. My home-building neighbors built accordingly after seeing the ultra efficiency here.

 

[SwiftShot]

Spray foam and moisture happen when you have hot cold sides. You get condensation building like in a tent. This typically happens with I think less than 2 inches of foam. There is an R value but I do not remember it. This will be based on your temps. Ie in Montana will be different than Florida. In shops I understand spray foam but retreo fit an attic I would use traditional. If you are building like I am a Barndominium, well foam makes sense as there is no attic.

 

[Swampcruiser]

Spray foam in the attic is risky unless the System is built for it- venting. Better off with loose cellulose blown in and a vented deck.

 

[elkguide]

Living in a colder climate, working construction and seeing the growing use of spray foam, it has a lot of plusses and a few negatives. As has been said, it does seal things up tight and it certainly makes heat retention excellent. If you spray your roof in the rafters, many shingle manufacturers automatically void any warranty. I watched a house that was fully spray foamed add an air exchange unit as the house was so tight and the homeowners felt that they and their children had all developed allergies and were sick a lot after a winter inside. The plus side for them was that they had heated a 3200 square foot home on just over a cord of wood during a colder than normal winter. If you have to move/add a wire after you have used spray foam it is a real nightmare. After saying that, when my daughter builds this summer, I'll be using spray foam in the walls and dense pack in the rafters.

 

[Wrench]

One of my friends built a post and beam type home. They did spray in. The day after it was obvious. You can heat the house with the heat from the refrigerator. Pretty incredible.

 

[dinajafer]

Closed-cell foam has been a game-changer for me in sealing up air leaks and adding structural integrity. One thing to keep in mind is that humidity can impact curing, so make sure conditions are right. If you’re in a climate with wild temperature swings, it’s worth considering a pro install. I had spray foam insulation Chicago handle mine, and it made a huge difference in comfort and energy bills.

 

[Weldor]

Curious, I read that a sealed house is a sick house? Airflow needed to prevent mold etc. etc. I know it was used alot in Canada before here in the US. I like the idea , but not sure.

 

[Coopsdaddy]

Use what’s been proven for decades.
Walls maybe,no way in attic.
May and may not have issues but a lot is determined by the climate.
I remember reading something on green building advisor years ago.
Spray foam industry is kind of shaddy.Most will be long gone 5-15 years later when you have issues and claim certain R values.
A R value is a R value and you can’t change that.
If you need R30 explain how you get that with a few inches of foam.
1 inch of closed,open,batts,cellulose etc all have a R value.The foam industry tries to convince you the air sealing makes up for there lack of R.

 

[bradmacmt]

I'm a general contractor - I build custom homes only. Typically I down-spray all lids from the attic side (2") and then blow in over that. Venting stays the same as a normal attic (soffit vents with a ridge vent). With some home designs there's no way to insulate the attic without urethaning the entire roof structure, in which case it's an 8" fill between rafters - then the attic is conditioned and venting is not required.

2x6 walls are typically 2" Urethane, and either an R11/13 batt over that, or cellulose with binder blown over the urethane. Crawl space walls are urthethaned, or if full finished basement, concrete walls are urethaned after studs are installed.

I never, and do mean never, build a house without urethane.

 

[mxgsfmdpx]

Part of the key for maintaining temps in living portion of the house and moisture management in the attic is proper air flow and venting.

Spray foam in the attic is not normally recommended unless you are doing a minimal amount in place of where we like to use the radiant barrier. If you want it done right but pricey, a combination of radiant barrier foam and batts and/or blown in insulation with good airflow is the way.

Spray foam works excellent for exterior and interior walls other than shower walls.

 

[bradmacmt]

Spray foam works excellent for exterior and interior walls other than shower walls.

I always urethane exterior shower walls. There's no reason not to if the tile installer is reputable and knows what he's doing.

 

[Beendare]

Spray foam is a game changer...IF;
1) the product is mixed right
2) its used correctly

It's not one size fits all- there is open cell and closed cell to be used in different situations. The insulating value of foam is far superior to Fiberglass.

IMO from years of doing this stuff; Loose fiberglass batts is crummy insulation. Rock wool batts and foam is fantastic

 

[displacedtexan]

Spray foam industry is kind of shaddy.Most will be long gone 5-15 years later when you have issues and claim certain R values.
A R value is a R value and you can’t change that.
If you need R30 explain how you get that with a few inches of foam.
1 inch of closed,open,batts,cellulose etc all have a R value.The foam industry tries to convince you the air sealing makes up for there lack of R.

How is my Sitka hoodie so much warmer and better at blocking wind than a cheap cotton hoodie?

There's definitely some shady guys running spray foam companies, same as every other small service business...

But science is real, and different chemicals have different R values.

There's a reason we don't build houses the way we did 20 or 40 or 60 years ago...

 

[gulfofmexicoflyfishing]

Icynene in a sealed envelope attic is a game changer. I build oceanfront custom homes in south Florida, and I can tell you we do it a lot. The recipe for success is a closed soffit, no ridge vents and a dehumidifier in the attic space. A/C is even better but not required. When it’s 95° and 90% humidity outside, and Bob from Michigan likes to set his thermostats at 68° there really isn’t much else that works.

I am not an engineer, but I rely on them daily for guidance on these things.