Shop Insulation

[Jake Helmboldt]

With the cold weather and various discussions about shop heating, I'm wondering about shop insulation.

My "shop" is a 2-car masonry garage (block w/ brick face). Other than the insulated doors I installed (there were none when we moved in), it is uninsulated. I plan to put fiberglass bats in the rafters and sheetrock the upstairs, but what about the block walls? I'm wondering a couple things:

1. Is it even worth insulating since masonry in itself is fairly well insulated?

2. Would it be worth the cost and effort to install foam insulation sheets (1" thick) to the walls and sheetrock over them, or would the R-value increase be negligible?

Any other suggestions? The shop is already tight so I don't want to lose much space by firring out the walls to install thick fiberglass insulation.

Jake

[Kyle Kraft]

Masonry isn't well insulated, it is a thermal mass. When its cold it is slow to warm and vice versa. Sit next to an exterior block wall during a Michigan winter and you'll know what I mean! I would try to insulate the block wall somehow and install some sort of vapor barrier, as moisture would migrate through the insulation and tend to condense on the cold block.

[Jim Becker]

My shop is also block walls. I furred it out with half-studs (essentially 2x2s), insulated between them and then put up my walls. (T1-11 or OSB, depending on which "generation" of shop space you are in. I also installed a poly vapor barrier and that really cut down on infiltration.

[Larry James]

Jake,

I insulated my basement walls with a product called Insulpink (intended for basement walls???). It is 1 1/2" thick and 2' wide. Easy to install on 2' centers with furring strips and cover with 1/2" sheet-rock. This would give you an R value of about R7 with a total thickness of 2".

As Kyle and Jim noted, a vapor barrier is necessary. OSB or a similar wall covering, as Jim suggested, would probably be better for durability and mounting stuff on the walls.

Larry

57000

57001

[Joe Chritz]

Check your insulation contractors for spray on polyurethane insulation.

1 -1.5" is all you need and it is fantastic stuff. I have both my house and shop done with it and have never been sorry.

It is a little more than using pink board, but the time factor made up for the extra cost in my case.

Also, as mention above you definately need some thermal break for that block wall.

Joe

[lou sansone]

although more expensive than the pink and blue board, I like cellotex for rigid foam insulation, it has the highest r rating, plus a reflective layer as well.

lou

[Jake Helmboldt]

So it would be vapor barrier, insulation, OSB (or other interior surface) in that order? Any reccomendations on affixing the barrier? I'm guessing the furring strips would hold it in place and then the insulation between furring strips, and OSB then screwed to the strips?

Joe, with the spray-on insulation, what do you do to mount a solid surface for wall material?

thanks for the tips. Jake

[Steve Jenkins]

I found a source for do-it-yourself foam insulation. I'm thinking of doing the floor in my house. Hardwood over crawlspace and it's really cold in the winter.
http://www.tigerfoam.com/

[Art Mulder]

Masonry isn't well insulated, it is a thermal mass. When its cold it is slow to warm and vice versa.
Yup, you've got a huge hunk of thermal mass there. Shame to insulate it on the inside and lose it's moderating effects. The ideal solution (from a thermal point of view) would be to insulate the outside of the shop. This gets all that lovely thermal mass inside where it will help moderate your temperatures. But that is likely a much more costly option.

(I have no idea how it would pay off in the long run, but I have just read a fair bit about thermal mass.)

[CPeter James]

although more expensive than the pink and blue board, I like cellotex for rigid foam insulation, it has the highest r rating, plus a reflective layer as well.

lou

The "R" rating is as I remember it is 7.2 per inch. I have 6" in my house ceiling and 4.5 in the shop. I put 1 3/8" on the inside on my foundation when I built a room in the cellar. Fir out the walls with studs on side and put the insulation in between and the Sheetrock over it. It will amaze you the difference. I use the Tapcon screws and construction adhesive to put the studs up. They will never come off.

CPeter

[Joe Chritz]

You would still need some kind of furring strip, which would go on before the insulation.

You would not need a vapor barrier as the urethane insulation is its own vapor barrier.

Joe

[Chris Friesen]

The ideal solution (from a thermal point of view) would be to insulate the outside of the shop. This gets all that lovely thermal mass inside where it will help moderate your temperatures. But that is likely a much more costly option.

There are two things to consider.

If you want to keep it the same temperature all the time then it makes sense to insulate the outside of the walls (and underneath the slab). This way the thermal mass will help even out temperature fluctuations. However, it will take a long time to change temperatures.

On the other hand, if you want to leave it cold most of the time and only heat it occasionally, then you want to *minimize* the thermal mass of the insulated area. In this case you want insulation inside the walls and on top of the floor. That way the insulated area can change temperature quickly.