Planning To Build a Shop/Garage, Insulation Question

[Milo]

Just in the planning stage for constructing a free standing multi-use, climate controlled, building to house motorcycles, tool benches, gun safe, a couple of exercise machines, storage, etc. probably around 24x36. I'm thinking a 12'x 24' carport on the end would make a good place to park the rotary cutter, rear blade, FEL with easy access from the 24' side.

So far I've decided on footers and block which will be insulated and the concrete floor poured to that, with at least one 4" (or 6") block exposed above the slab and framed walls resting on that. That rim of block will be directly exposed to the outside and radiate cold right in so it'll have to be covered. My thought was to have the 2x4(or 6") wall flush with the blocks on the inside, filling the wall cavity with fiberglass, covering the inside studs straight down to the floor with foam board such as 1" T&G blue board, then drywall. Am I on the right track here or is there a better way? Any problem with rigid foam board under drywall? It'll be kept heated or cooled all year so I want it very well insulated. Exterior will be Hard-plank to match the house.

 

[hslogger]

I vote for two by six walls. just say no to 2 by 4 for rigidity and insulation area. I would rather see you pour your footer and stem wall, then pour your floor. Nothing wrong with foam board but I again, vote for fiberglass insulation.

 

[Milo]

Thanks hslogger I may go with 2x6" that's what I used for the house.

Of course all the wood (even 6") framing, with OSB and Hardi on the outside, and drywall in, is only what R6? Whereas 2x4 at R4, plus 1" foam board at R5, gives R9 at the framing and R18 over the cavities. The cold spot would be the row of block covered only with 1" foam and drywall.

 

[Raspy]

A common way to insulate basement walls is to shoot 2X4 PT plates against the wall with a powder activated nailer. Then put rigid Blue Board insulation between those plates, or studs. You could even nail on a second stud over the first and double the insulation thickness from 1 1/2" to 3". Then make the inside of those even with the wall studs that sit on top of the stem wall. Then your sheetrock can run down the wall to the floor with no offset. The Blue Board is water proof and closed cell. It's fine in that environment.

I built my house with 2X6 studs and used a blow in insulation that goes in before the sheetrock. They staple cloth over the studs and fill the bays with a hose by blowing it in through a slit in the cloth. This is better than bats, with no voids and ends up at about R20 or better.

An excellent way to heat would be to install PEX for radiant heating. Run the rebar on 12' centers, tie the PEX directly to it with rebar ties and hold the PEX back a foot from all exterior walls. You'll get minimum heat loss and a fine place to work.

 

[Milo]

Rather than fur the row of block I was just thinking of covering it completely. Basically there'll be 1" foam between the concrete pour and blocks so thought to let it continue straight up the exposed block and framing to the bottom of the trusses making a flush wall. doesn't leave an easy way to attach drywall at the bottom though. May have to put a nailer strip down on the bottom.

Floor heat would be really nice but I wouldn't think it'd be as effective bringing the area up to temperature after being set back. My thinking is in Winter to keep the building say 55 degrees when I'm not around for days at a time, then turn it up when I plan to use it. Same in Summer let the AC keep it maybe 78 then bump it down a few when I use it. So thinking a mini-split system. But open to options, thanks.

 

[MossRoad]

You should run rigid foam insulation up the outside of the block from the footing to the base of the wooden wall and cover the top of it with flashing between the block and wood, like this...

http://insulation.owenscorning.com/...s-crawlspaces/foam-insulation-exterior-walls/

 

[Ehanson]

Very cool to build a shop, ours is 3 years old now, it is 26 X 32, whatever the size, it is far bigger than the 12 X 24 Garage I was in previous to the shop.
Definitely 2 X 6" construction.
The only difference I would change is insulating the floor. I would spend the money and do the insulation and good moisture barrier in the floor.
Here is some pics to dream on. Thank goodness for good friends and family, they helped immensely.
Dropbox - P1951.JPG
Dropbox - DSCN4335.JPG

Notice how quick a shop can fill. The furniture I made, the sailboat is gone.

 

[Milo]

Moss that looks good but if possible I'd rather the exterior of the block be exposed up at least 8", in the summer it's easy to trim against with a string trimmer or lay mulch up to and in winter snow and melting snow lays against it.

 

[bcantell]

Mossroads graphic is awesome for a building with a cellar, but not for a building with a poured floor with block or poured walls. You're on the right track but you want the floor to rest on compacted soil up to the wall, or even better, on a shelf. I wouldn't have insulation board between the floor and wall, if that's what you're thinking.

You can solid insulate the exterior of the foundation walls up to grade, insulate under the floor, then insulate the interior of the walls over grade. I don't see any reason you can't insulate the interior with solid from the wall to the floor except you'll have to build out the walls or have a shelf. You're electrician might not like it much.

2x6 for sure, and you could go 2' O.C. to save $$$.

I'd use Green Zip for the wall sheathing and Red Zip for the roof sheathing and tape the walls real good, I only tape the roof if I'm not shingling right away. I wouldn't use OSB on a dog house.

You haven't said what your plan is for the roof system, but I assume you're drywalling & insulating the ceiling.

If cost is not a concern and you want the best there is, closed cell spray insulation is the way to go. It will cost a lot more, but will save in heat and A/C for the life of the building. Plus it adds stability and sound proofing to the building.

Adding up the cost of fiberglass and solid on all the walls, spray might not be that out of line cost wise.

 

[thepumpguysc]

I built/had it built the same dim..but mine is metal.. I put 2" foil faced 4'x8' foam board between the studs, cut it to fit & a very easy install using a circular saw.
I don't have to worry about the cold as much as I do the heat.. here in South Carolina it gets over 100*..
After the install, the building was cool as a cucumber in the mid day heat in a METAL building.. I put the foil face to the outside to reflect the heat..
The big box stores wanted OVER 30.00 a sheet & NO delivery, but I found a small rural wood distributor in the country that ordered the board for 20.00 a sheet DELIVERED.. I still have 10 sheets left over..
To bad you weren't closer..