Foam Insulation

[Louis Rucci]

I'm still planning on using foam insulation for my shop.

I had a conversation with my neighbor, works in construction, and he told me it would cost $40.00/linear foot. He was basing this on a 2x4, but my shop was constructed with 2x6.

Since close cell foam insulates on the order of R6-7/inch, 5.5" would be around r33 - 49.

Is that cost reasonable or is he off?

My shop is 30'x28'x10'. ACtual framing is 8', as the first 2' are concrete block.

Thanks,

Louis

[Thom Sturgill]

Its a cost vs price issue. The price of foam may be higher, but the cost of ownership over several years is lower due to lower heating / cooling costs, lack of mold issues, etc. I plan on using foam on my retirement home and shop when I build in about 5 years.

[Jim Becker]

Closed cell spray foam is about R7 per inch and it's not unusual for them to overfill a bit "just because". It also provides a total vapor/air infiltration barrier as well as additional stiffness to the structure that you will not believe.

With your 2x6 walls, you can have them spray R19-R25 or so and still have space in the wall for future wiring retrofit if need be. I have a couple 2x6 walls in our addition that let me make that representation. (Most of our structure is 2x4 "because" we specified the closed cell foam insulation...the money saved in lumber went toward some of the higher initial cost of the foam)

My initial cost was obviously higher than using 'glass, but as Thom says, long term, I'll come out way ahead. The HVAC system in our addition runs very little compared to the unit in the original structure and that's because we have that sealed envelope in place.

[Eric Haycraft]

Closed cell spray foam is about R7 per inch and it's not unusual for them to overfill a bit "just because". It also provides a total vapor/air infiltration barrier as well as additional stiffness to the structure that you will not believe.

With your 2x6 walls, you can have them spray R19-R25 or so and still have space in the wall for future wiring retrofit if need be. I have a couple 2x6 walls in our addition that let me make that representation. (Most of our structure is 2x4 "because" we specified the closed cell foam insulation...the money saved in lumber went toward some of the higher initial cost of the foam)

My initial cost was obviously higher than using 'glass, but as Thom says, long term, I'll come out way ahead. The HVAC system in our addition runs very little compared to the unit in the original structure and that's because we have that sealed envelope in place.

Another thing to note is that since the insulation is that much better, the size of the heating/ac unit can be smaller which also helps to offset some of the initial costs. These days I think that anyone who can do foam would be crazy not to. The long term savings are good right now and will only get better as energy costs increase.

[Jeff Wright]

Make sure you use a reputable experienced contractor. I have heard some horror stories about foam emitting unpleasant or unhealty vapors and odors that continued to give off nasties. Having said that, I plan to use rigid closed cell foam panels when I insulate the open ceiling in my 2-car garage shop. Currently my mini-split system is heating and cooling my neighborhood as well as my shop.

[Jim Becker]

Jeff, I've used the closed cell foam twice now...under the great room a few years ago and now for our entire 2000+ sq ft addition. The only odor was during actual installation. There is no off-gassing that I can detect.

[Joe Chritz]

1 inch is all that is "needed". Anything more than 2.5 is overkill.

For example, I have a 24x30 shop. One wall is purposely left R13 fiberglass to get waste heat to the storage area on the other side. I have 1 8 foot mild insulated door. 10 foot ceilings with 16" of celllose loose fill.

I heat with a Volgazang boxwood wood stove (very small) and a 45K BTU HotDawg. It isn't unusual to get cooked out when the temps are in the 30's and sunny outside. I put propane in the pig on 11/07/07 (100 gallons) and I am still using that now. Wood only gets used when I am out there.

I have 1 inch on the walls of closed cell spray urethane.

There is more to the foam then R factor alone. Full air barrier, heat reflective, etc.

Joe

[Louis Rucci]

OK, our shop are comparably sized (28x32).

What is the "pig".

Having wood all year long isn't feasible unless I could get it for free, and that's not going to happen.

I'm going to look into your stoves anyway. Never say I left a source unresearched.

[Don Abele]

...I have heard some horror stories about foam emitting unpleasant or unhealty vapors and odors that continued to give off nasties...

Jeff, the only vapors I've heard of associated with the installation is actually water vapor. It comes off as steam as the reaction is a exothermic one which produces heat which vaporizes the water in the foam.

The old spray foam was bad as it used formaldehyde in the formula - that stuff is banned now.

...What is the "pig"....

Oil Tank


Be well,

Doc

[Bryan Berguson]

I'm still planning on using foam insulation for my shop.

I had a conversation with my neighbor, works in construction, and he told me it would cost $40.00/linear foot. He was basing this on a 2x4, but my shop was constructed with 2x6.

Since close cell foam insulates on the order of R6-7/inch, 5.5" would be around r33 - 49.

Is that cost reasonable or is he off?

My shop is 30'x28'x10'. ACtual framing is 8', as the first 2' are concrete block.

Thanks,

Louis

That price sounds pretty close. When I had closed foam sprayed in my basement about 4 years ago, it was 1.25 for the first inch and .75 for each additional inch.

I have soft foam in the walls of the house but I don't remember what it cost us. That's the stuff they completely fill the wall with and then cut off the excess. There is a Soy product now that is practically all natural. The soft foam doesn't have the R value of hard foam but it's generally cheaper and fills the wall full. I've a brochure on the Soy at work. If you're interested, I can get the company name.

The other guys are right about finding a good installer. A friend of mine had a nightmare with his new house and soft foam. An 8000+ sq ft home and they ended up taking ALL of the foam back out after they found 1-2 inch air cavaties between the wall and the foam. Of course they sprayed it on frost covered walls but they were sure that wasn't the problem - yeah, right!

Another plus for the closed cell foam is it adds structure to your building. It glues everything together and makes your walls one complete unit.

One more thing to do, have them foam the tops of your top plate in the actic. That's always a problem area to insulate well but the foam does it perfectly. If you had a basement, the wall space between your floor joists should be done too.

I'm not sure there is such a thing as "too much insulation" but there are alternatives to filling the wall full. You could spray 1 or 2 inches and then put fiberglass bats in. I have it in my house and garage and have been very happy with it. Although, if I were building again, I'd consider dense packed cellulous. It's so dense that it doesn't settle, it's also fire proof and treated with borax (I think) which greatly discourages rodents and insects.

Bryan

[Michael Gibbons]

So there are at least two types of spray-in foam insulation, correct? One that only fills a portion of the cavity and one that overfills the cavity and needs to be trimmed flush. Which one is more efficient?

[Jim Becker]

Michael, closed cell foam is the most efficient...~R7 per inch. You "can" fill the stud bay, but it's not necessary to meet code which is typically R19 for walls these days. My installer for the addition accidentally overfilled the roof rafters, so we have, oh, about, let's say...R50+ up there. No extra charge.

[Bryan Berguson]

So there are at least two types of spray-in foam insulation, correct? One that only fills a portion of the cavity and one that overfills the cavity and needs to be trimmed flush. Which one is more efficient?

The hard foam has a higher R value per inch. I haven't done a direct comparison in cost per R value but that would be interesting information. They both effectively block air blowing through your walls and neither require a vapor barrier.

Bryan

[Ted Jay]

The hard foam has a higher R value per inch. I haven't done a direct comparison in cost per R value but that would be interesting information. They both effectively block air blowing through your walls and neither require a vapor barrier.

Bryan

Also availiable is a DIY kit for the two part and one part foam. It is the Petroleum oil based foams. http://www.fomofoam.com/

The soy oil based foam is more "green". I haven't found a DIY for this type. I think you have to get their people to come in and spray it. http://www.biobased.net/

The amount that each expands is also different. The soy base one touts 100 times, and the petro base 6-7 times.

I have been looking at both, wanting to apply in the extension that I'm doing on the shop, for storage. Then do the shop after I move everything in the storage area.

I know with the DIY kits I have more control over time, as I can move things around as needed, between spraying.

Ted

[Eric Haycraft]

I know with the DIY kits I have more control over time, as I can move things around as needed, between spraying.

Actually, there isn't much work time. You have 30 seconds of downtime per nozzle which goes by very quickly. I tried to test the limits of that and now I have 4 stud bays to redo. The foam is a 2 person job.. one spraying.. one manning the tanks/heaters.

In terms of cost, I hear that having it done is about the same cost as doing it yourself. I wanted to try something new and wanted flexibility in timing, so I did it myself. Also, spray foam costs about the same as foam sheets that you buy at the BORG, but the BORG sheets are a PITA to seal and will cost more when you factor in the hundreds of cans of great stuff needed to seal all gaps.

To get a good r-value, the DIY way is to spray 1" and cover with fiberglass. The foam seals everything and provides a great r-value and air barrier.

1" sprayed pretty well and didn't take too long, but 3" would have taken forever to do. The DIY stuff takes a while to spray with...much slower than what the pros use. If you want more than 1" it will take a very long time and I would not suggest trying to do it yourself.

In my weeks of searching, I never found the 100:1 expanding stuff for DIYers, so I doubt it exists.