Foam Quote - need input

[jethrodawg]

Hi folks, I live in cold climate (NH) with a 24x26 garage. Plan is to insulate and drywall. Area above garage will be future finished bonus room

I got quote to have 3 inches of 2lb closed cell foam sprayed in ceiling joists and the common wall between house and garage.

Essentially the ceiling and wall are wide open with no obstructions so it's as easy a job as they come. 10 ft tall wall (minus the door to house)

Ceiling is 24x26 = 624 sq ft
Wall is 24x10 = 240 sq ft (minus door)

Quoted $3358. Seems high but want to see if this is in the ballpark.

He also said can do full 4.5 inch "code" level foaming but he said 3 inches is plenty. That quote was $4489

I really want to do foam but questioning the higher cost vs fiberglass. I asked how much just for foaming the ceiling and I'd do the walls with batts.

 

[kj_mustang]

Get more than 1 quote. I had three quotes done. 2 companies gave about the same price quote but the third gave me a quote I could live with. In your application, I would only spray 2" closed cell as that will give a complete seal and then go over the foam with batts if you want more R value.

 

[tjpavlov]

That doesn't sound way out of the park, unfortunately. I would consider it for at least the floor of the bonus room. I have the same situation. We went with fiberglass for the house because of cost ($2,000 vs. $16,000 quoted for sprayfoam). Although I am happy with the decision, the room above the garage is always a couple of degrees cooler in the winter.

If I could do it all over again, I would do the ceiling of the garage in foam. It also gives you a much better seal to prevent fumes from going into the bonus room.

 

[tomroblee]

I can't comment on the absolute cost of spray foam, but I know that it is expensive.

We had a similar situation when we had our rural house built. It is a 36' x 64' footprint with about half of the first floor being a garage. It was built with room-in-attic trusses. The 12/12 pitch roof yielded an 18' x 64' room upstairs with 8' ceilings.

When the trusses arrived at the building site we discovered that the metal plates used to join the truss parts protruded into the room at the corners where the walls and ceiling met. The vertical walls were 2x4's which limited the amount of insulation we could use. Our solution was to insulate the side walls of the upstairs with 3 1/2'" fiberglass batts--THEN COVER THE WALLS WITH 2" RIDGID FOAM BLUEBOARD. The blueboard was thick enough to cover the metal plates. The room was finished with drywall on top of the blueboard using extra long drywall nails.

We used blown cellulose insulation over the first floor ceiling and again over the second floor ceiling. It's an unusual approach, but it worked for us. The blueboard provides R10 insulation and limits air infiltration (the seams were taped). I think that 2" blueboard costs about $1 per square foot.

 

[Autorotica]

Quotes I have been seeing are right at $1 per inch per square foot for closed cell...

Chris

 

[jethrodawg]

Get more than 1 quote. I had three quotes done. 2 companies gave about the same price quote but the third gave me a quote I could live with. In your application, I would only spray 2" closed cell as that will give a complete seal and then go over the foam with batts if you want more R value.

Actually I have had two foam applicators state NOT to do flash + batt in a cold climate. Either foam or batts but not both.

Read this article: https://www.finehomebuilding.com/tool-guide/articles/why-flash-and-batt-makes-sense.aspx

It *might* makes sense in warm climate, but definitely not cold climate.

 

[rburke65]

No expert here but I have never read where the spray then fiber glass batts were not a good idea. And if you can afford it. Well, energy is not going to get cheaper....only more!

 

[jethrodawg]

No expert here but I have never read where the spray then fiber glass batts were not a good idea. And if you can afford it. Well, energy is not going to get cheaper....only more!

You can read here: http://www.ntcinsulation.com/the-insulation-lab/flash-and-batt-risky-in-cold-climates

Depends on application.

In my case doing exterior walls with flash and batt would be bad idea.
Cathedral/sloped ceiling in cold climate, flash and batt also bad idea.

 

[kj_mustang]

Actually I have had two foam applicators state NOT to do flash + batt in a cold climate. Either foam or batts but not both.

Read this article: https://www.finehomebuilding.com/tool-guide/articles/why-flash-and-batt-makes-sense.aspx

It *might* makes sense in warm climate, but definitely not cold climate.

Rebuttal tech.

http://www.buildingscience.com/documents/reports/rr-0912-spray-polyurethane-foam-need-for-vapor-retarders-in-above-grade-walls

 

[Autorotica]

Actually I have had two foam applicators state NOT to do flash + batt in a cold climate. Either foam or batts but not both.

Read this article: https://www.finehomebuilding.com/tool-guide/articles/why-flash-and-batt-makes-sense.aspx

It *might* makes sense in warm climate, but definitely not cold climate.

Flash and Batt was done in my home when I built it 20 years ago. I have nothing bad to say about it.

Chris

 

[jethrodawg]

Rebuttal tech.

http://www.buildingscience.com/documents/reports/rr-0912-spray-polyurethane-foam-need-for-vapor-retarders-in-above-grade-walls

Did you read the conlcusion? Exactly what I had posted and certainly not a rebuttal.

They also did not use a 1 inch "flash and batt" either. They did 2 inch which in my application negates any need to fiberglass anyways.....

And for the open cell foam, they even conceded that you have to be careful of humidity levels in a cold climate even at higher thicknesses.

 

[kj_mustang]

Yes I read it. The conclusion states, "Closed-cell (about 2 pounds per cubic foot density or more) spray foam applied in thicknesses of over 2” (50 mm) will control vapor diffusion to safe levels in all climates up to 10000 HDD and interior winter-time relative humidities of up to an over 50%RH. As thickness increases the level of diffusion control increases." 10,0000 HDD is a very cold climate. New Hampshire is in the range of 7,000-7,500 HDD. The reasoning for having to still use batts is that 2 inch of closed cell foam is only rated at R-13 and some areas that will not meet code requirements. I said in my first post that I would spray 2" foam and then use batts. I never said 1 inch.

 

[jethrodawg]

Yes I read it. The conclusion states, "Closed-cell (about 2 pounds per cubic foot density or more) spray foam applied in thicknesses of over 2” (50 mm) will control vapor diffusion to safe levels in all climates up to 10000 HDD and interior winter-time relative humidities of up to an over 50%RH. As thickness increases the level of diffusion control increases." 10,0000 HDD is a very cold climate. New Hampshire is in the range of 7,000-7,500 HDD. The reasoning for having to still use batts is that 2 inch of closed cell foam is only rated at R-13 and some areas that will not meet code requirements. I said in my first post that I would spray 2" foam and then use batts. I never said 1 inch.

Code where I live would be R19 (exterior walls). The cost adder between 3 inches vs 2 inches and then adding batts becomes false economy. Going from 1 inch foam to batts I could see.

Interestingly, my foam guy said unless I was adamant about meeting code in the garage exterior walls, he indicated that the 2 inch closed cell in the walls with code thickness in the ceiling is what he recommends for people where cost is a limiter. He did state that he did not recommend adding the batts even with the 2 inches of foam in the garage.

A garage with warm cars, snow, and rain makes for a wet environment. Much different than the interior of the main house.

Kinda of a moot point as I'm going all foam at this point and taking my lumps since I want to do everything I can to avoid the usual hot/cold bonus room issues.