Spray foam vs batt insulation

[andis65]

so i have a 30x40 with 12 foot ceiling that i need to insulate, i live in upstate ny so it gets rather chilly here in the winter months. I already have radiant heat concrete floor but cant decide if spray foam insulation is worth the extra cost. I have also heard of people doing skim coat spray with batts rolled over top. Any good stories????

 

[BrianC636]

My 60 x 40 x 12 is foamed and I LOVE IT!

 

[Al Bundy]

I considered spray foam and discovered that the cost was 3 times as much as fiberglass. And that was with me doing the labor. Hard to justify when the ROI would probably be 50 years.

 

[bgarrett]

Return on Investment begins immediately with spray foam.
It might take 50 years for heating/cooling costs to pay off but spray foam gives immediate results that make it worth the cost

 

[duneslider]

Personally, unless you are in this shop everyday and you have it heated all day everyday I don't see it being worth it. You'll never see the ROI. Not sure what is so magical about it that you would see the direct results from day one.

It is fantastic stuff but if this is just a garage/shop that you mess around in on the weekends will you really notice the difference?

 

[kb2tha]

Spray foam will cut down drastically if not nearly completely the infiltration factor. Batt insulation will never do that as well. Most heat loss is through infiltration. In my garage, I used 3-4" of open cell spray foam and then covered that with 4 x 8 sheets of rigid urethane insulation (r7), vapor barrier and then sheet rock. The cost would have really added up to foam the ceiling so I used about r50 worth of Attic Cat blown in. Floor has 2" rigid under the concrete. Works for me.

 

[DynoDave]

Hard to justify when the ROI would probably be 50 years.

I'd have to live (and work in the garage) until 98 y.o. to break even? I honestly don't see THAT working out for me.

 

[Camper]

I work in a metal building that was spray foamed a few years ago....liked it so much I am having the house done as I am remodeling it.
I was told ...yes it is double the cost but 3 times the efficiency.
I will get the garage done in time.

 

[gesoffen]

Considering you are running a radiant floor system, you'll get the payback of a spray foam install faster than most typical garage/shop owners would. With radiant heat, you'll be setting the t-stat and forgetting it for the season due to the LONG recovery times (vice forced air where you'd consider turning off/setting back when you're not in the shop).

Is it worth it - your ROI will depend on how cozy you set the t-stat but spray foam is a far superior insulation than glass. If budget is a big concern, I'd at least consider a flash and bat approach to get the air sealing benefits of foam.

 

[78C-10]

I am in the same situation and have the same foot print, 30x40 with 10 foot ceilings. I got a quote for $3200 for 2 inches of closed cell foam. I figured $1600 for 1 inch, I have read around here that 1 inch can condensate and that 1 inch is hard to spray. Is this true? I would like the sealing factor but can not afford full blown 2 or more inches of spray foam. I was thinking of the flash and batt idea as well. I won't go this route though if 1 inch is going to condensate.

 

[theoldwizard1]

I considered spray foam and discovered that the cost was 3 times as much as fiberglass. And that was with me doing the labor. Hard to justify when the ROI would probably be 50 years.

50 years ! We need data !!

Yes, the ROI is long, but is it really 10, 20 or 50 years ? Unfortunately, you will have to hire a specialist to figure this out and even then I would not expect the answer to be 100% accurate.

 

[NUTTSGT]

Any insulation, once put in, will immediately start showing a return on investment.

All insulation is an investment, some might work better than others. I believe the ROI will vary on shop to shop, it's something needs to take into consideration, time spent in the shop, temp shop is kept at, what you are using for heat and weather inyour location.

I keep my shop warm, I'm out there 2 out of 3 days (many hours) but I heat with wood. My annual heats costs about a hundred bucks. If it cost me $4k to spray foam my garage to save me 50 bucks, I'd never see the completed ROI.

 

[#1SomeGuy]

When I was looking at my basement it was $2500 for spray foam by a professional or $600 for roxul batt insulation and vapor barrier installed by me (the better rock wool stuff, not fiberglass). No way I could justify over 4 times the price for insulation. The other thing is roxul is a fire barrier and can be left exposed but spray foam will burn/melt, release toxic gas and thus has to be covered with drywall immediately which is what really sold me.

 

[socapots]

Well said.
In my reading depending on the thickness of spray you go with you may still need more insulation and vapor barrier.
If you can afford it and want the "best" then go for it.

 

[Kevin C]

so i have a 30x40 with 12 foot ceiling that i need to insulate, i live in upstate ny so it gets rather chilly here in the winter months. I already have radiant heat concrete floor but cant decide if spray foam insulation is worth the extra cost. I have also heard of people doing skim coat spray with bats rolled over top. Any good stories????

I like the idea of using a combination of materials. From what i have read, the first layer of spray foam insulates and adds reduces air infiltration, fiberglass on top of that gets you the rest of the R value at a lower cost.

The other combination that seems to work well is to use sheet of foam and bat insulation. That's what I'm doing on with my garage. I have R15 in 2x4 walls covered with R10, 2" foam sheeting. Same thickness as a 2x6 wall but the effective R value is about R5 higher. A good part of that is getting rid of thermal bridging from the wall studs.

I agree on air infiltration as a major source of heat loss. I made sure that every joint on every framing / insulation bay was sealed before I put the fiberglass in. Many houses are built with the foam to the outside. For my garage I'm putting it to the inside.

Hanging sheet rock will be interesting.... But I will end up with some nice wide window sills.

While not a very scientific assessment, I did notice that as I put up each sheet of foam over the studs with fiberglass bats, the room started to feel a lot warmer.

View media item 28964
Time and a few more paychecks will tell.

 

[kb2tha]

1 inch is hard to spray. Is this true?

My installer said the same thing since the product expands so quickly that anything under 2-3" is hard to control the thickness. I ended up paying for 3" and still had as much as 4+ in spots.

 

[Al Bundy]

50 years ! We need data !!

Yes, the ROI is long, but is it really 10, 20 or 50 years ? Unfortunately, you will have to hire a specialist to figure this out and even then I would not expect the answer to be 100% accurate.

Just a hyperbole. In my case it would take a long, long time to recoup the cost. I carefully installed adequate amounts of fiberglass and sealed everything that could cause infiltration. I'm 100% certain the monthly savings on heating costs would be absolutely minimal. Especially since the garage doesn't get used on a daily basis.

 

[newhollandpuller]

I too have a 30X40X10 (Pole Barn) with r-19 fiberglass in the walls - but I had them wrap and tape the exterior with single bubble thermal insulation (white on one side and shiny on the other with bubbles lookslike shipping wrap to me R-4or R-5) and they foamed (the stuff in the can)around all the windows and doors. Then when they came and finished the interior walls with metal I had them wrap it again with the single bubble and tape it. The thermal wrap cost an extra $400 out side and $400 inside. I also have about 48" of blown in insulation in the attic and it is very comfortable even when it was 0* outside and the wind was blowing you wouldnt know it and the cost for me was 1/3 of what they wanted to spray foam it. I keep it 65* all the time and it has been using about 10 gallons of propane a week.

 

[snorky18]

spray foam = high $ high performance
fiberglass = low $ low performance

The happy medium? wet blown cellulose for the walls, dry blow cellulose for the attic.

Strictly financially speaking, in a shop you only spend a part of your time in, spray foam would not make sense.

 

[Falcon67]

My supervisor just built a house using a spray foam envelope technique. There is no real comparison between that and regular blown in as far as air leakage and insulation goes. Yes, the price is up there but the benefit starts immediately and - as far as we know - never deteriorates. One advantage from a DIY perspective: If you go up in his attic, you can see everything. Every wire, every fixture - all of it. No problem servicing or adding anything. No insulation to pack down or move, etc. It's weird, actually. The house is so tight that they had to design make up air for the fire place and the kitchen/bath venting.

 

[walrus]

. ROI doesn't include comfort,

 

[DynoDave]

This is an interesting topic.

On this approach of spraying a thin layer of foam...say an inch for argument...then using glass...how do you get the batts to fit properly? I thought compressing the fiberglass batt was the kiss of death for it's efficiency as an insulator. Do you guys shave part of the batt thickness and width off?

 

[jimbbski]

I think that the "compression" question is not an issue. For example if you have a 2X4 wall, which is really 3 1/2 inches, subtract 1 inch for the foam and you still have 2 1/2 inches of space where you can install R13 glass which usually is listed as 3 1/2 inches thick. The glass is compressed but it should still be effective.

 

[mopar65]

i was skepitcal about the foam then i decided to go with it.best decision i have ever made.i have 2 inches closed cell.not only is it great for heating it increased the strength of the building greatly.just my opinion

 

[backintheday]

I am in the same situation and have the same foot print, 30x40 with 10 foot ceilings. I got a quote for $3200 for 2 inches of closed cell foam. I figured $1600 for 1 inch, I have read around here that 1 inch can condensate and that 1 inch is hard to spray. Is this true? I would like the sealing factor but can not afford full blown 2 or more inches of spray foam. I was thinking of the flash and batt idea as well. I won't go this route though if 1 inch is going to condensate.

I just built a house and did 1" of closed sell foam and the rest with fiberglass. When I build a shop I will do the same thing. It really quits things down ( wind where I live can get bad) and locks the house down!! Cost was around .95 a sq ft. Never heard about a condensation problem but it's pretty dry where I live.

 

[911mike]

Keep in mind energy never gets cheaper. What is a $50.00 a month saving today will be a $100.00 a month savings in the next 10 years. And will be $200.00 in 20 years. I sprayed foamed my vacation home 11 years ago and the cost was just over double. At that time it was $2700 more. Now with $3.50 a gallon propane our annual heating and cooling runs about $3500. If you figure the foam is only 10% more efficient that's a $350 per year savings. I think 10% is very conservative. I think the foam has paid for it's self in 8-10 years.