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Building/Insulation questions

bczoom

Super Moderator
Staff member
GOLD Site Supporter
Well, Mrs. Zoom just asked/requested (told...) me to finish 2 more rooms in the house.

The garage needs the ceiling drywalled. The paper on the insulation was stapled to the ends of the 2x4's so I can't use glue without a re-do. Think it'll be OK with just drywall screws or should I change the insulation?

I have another room under the garage which is the other one I need to finish.

The construction method will be such that I cannot build a standard framed wall (without changing a lot of plumbing and electric) and will need to anchor the studs directly to the block wall using Tapcons. This method will work better if I lay the 2x4's flat to the wall (opposite to the way you would normally frame it).

Due to the reduced space, I was going to use the 1" foil faced foam insulation board (polyisocyanurate). Should I put the insulation on the block wall then put the studs over it or should I cut and fit between the 2x4's? The former is easier but I'm thinking the latter would make it more secure. Thoughts?
 

Junkman

Extra Super Moderator
I would use 6 Mil Poly over the insulation and then use 1" x 2" furring strips across the 2" x 4" framing and attach the sheet rock to this. If you sheet rock a garage, building codes usually require 5/8" fire code rated sheet rock. On the walls, I would use the foam insulation board, covered with the poly for a vapor barrier and the 1" x 2" furring strips also before putting up the sheet rock. 6 Mil poly everything to keep the wind out and the moisture in so there is no migration of moisture to the insulation. I even put 6 mil poly under the cement floors before pouring them. My garage and cellar floors are always dry and not dampness or musty smells...... Junk...
 

Av8r3400

Gone Flyin'
1/2" 'rock is only required on the wall(s) that are between the garage and the living space. (Code here in Wisconsin.)
 

beds

New member
I put up that polyisocyanurate and it must be sealed to be effective. I went that route because it gave me the best r-value per inch. I would say that cutting it to fit between your studs would make its benefits useless and you may as well go rigid styrofoam. You will get a far better insulation if you can insulate between your studs and the exterior wall. Studs act as a conductor of the heat and cold and putting that foam between the cement and the studs would be your best insulation solution.
 

johnday

The Crazy Scot, #3
SUPER Site Supporter
Brian; I'd do to it similar to what Junkman and beds both said, in that, I'd use some 6 mil poly directly on the concrete wall, install your sheets of foil face polyisocyanurate, then face it with 1X whatever firring strips fastened with the tapcons. Then put up your finish wall material fastened to the firring strips. By putting that poly directly over the concrete, you can get by with plain old SPF lumber, and not worry about moisture getting to it and eventually rotting out.

In your garage, you may want to check with your building dept as to what thickness drywall to use. In my parts, the dept. wants either 2 layers of 1/2", or one layer of 5/8" on the cieling and adjacent walls to living spaces. Also the service door betwixt the living space and the garage has to have a 1 hour fire rating, and a self closer.

As building codes differ in even parts of the same counties, I'll always recommend to ask your building dept. That is what they are paid for, to help YOU.:burp::burp::tiphat:
 

Cowboyjg

Country Club Member
Site Supporter
Brian,

Typical practice.....foam board attached to block wall (attachment methods vary)....tape seams of foam board......attach 1x material (size of 1x and attachment methods vary based on degree of anal retention)....always good to use PT for furring regardless (borate treated is less expensive than ACQ)....run 1x4 or 6 horizontally at floor and ceiling with vertical strips in between (allows for attachment of trim material if desired).....attach drywall...(glue and screws or just screws...see note about 1x)

In truth there are so many thing you can do to enhance your situation but where do you draw the line? That will have to be your call
 

johnday

The Crazy Scot, #3
SUPER Site Supporter
Cowboyjg said:
Brian,

Typical practice.....foam board attached to block wall (attachment methods vary)....tape seams of foam board......attach 1x material (size of 1x and attachment methods vary based on degree of anal retention)....always good to use PT for furring regardless (borate treated is less expensive than ACQ)....run 1x4 or 6 horizontally at floor and ceiling with vertical strips in between (allows for attachment of trim material if desired).....attach drywall...(glue and screws or just screws...see note about 1x)

In truth there are so many thing you can do to enhance your situation but where do you draw the line? That will have to be your call

:a1::thumb::a1::thumb:
 

johnday

The Crazy Scot, #3
SUPER Site Supporter
OhioTC18 said:
Yeah right, tell that to the hundreds of contractors I deal with :whistle:
Know what ya mean Jerry. I've heard all the same crap you probably have. Most new inspectors are surprised by my attitude towards them. I let them know up front that I'm not trying to be smarter than they, and don't need any game playing. All I ask, is you see something I could maybe do better, let me know. And that I'm not challenging them when I ask a question. I feel if more GC's etc. would work like that, it could save a lot of problems. I've had problems with only one building inspector, and one state electrical inspector in the last 23 years. That's all. The inspectors job is to promote safe practices, and he and the contractor should both realize that.:respect:
Now, time for another Killians my man!!!:burp::burp::tiphat:
 

bczoom

Super Moderator
Staff member
GOLD Site Supporter
Thanks guys.

The concensus is to put the foam on the wall first and not put it between the studs.

I did use the poly plastic in the rest of the basement but thought I wouldn't need it in this area as most of it is above grade. The parts that are below grade have a 3' wide french drain all the way to the footer so I figured the moisture would be less. I'll put the plastic in anyway.

I'll downgrade from 2x4's to 1" furring strips which will actually help in other ways as well (like not having to buy new boxes of Tapcons at $25/box...).

The horizontal strip at the bottom will be a little different. One of my issues is that I have 1" sched 40 pipe along the wall as the drain for the A/C. My foam and furring strips will then be hung approx 1.5" from the floor due to the pipe. Once everything is in except the drywall, I'm going to use a 5/4 decking board as a baseboard and then run the drywall down to sit on that. It'll be screwed in so I can remove if/as I need access to that pipe. It'll also be nice as this area has been prone to getting some water in the past. If I do get water, it'll be easy to pop off the 5/4 board and the rest will be fine. When I go to the lumber yard, I'm going to buy a bunch of 4" S&D pipe and dig a new trench to catch the rain from the roof.

Mrs. Zoom is down there putting the 1st coat of Dry-Loc on now so I guess I'll be hitting it later in the week.

Ohhh. On the fire barrier issue in the garage. Our area does require 5/8" on the wall attached to the house. This was already in place (as it was needed before the cert. of occupancy would be issued). It's not required for the ceiling which is all I'm doing.
 

johnday

The Crazy Scot, #3
SUPER Site Supporter
Brian; that 5/8" drywall must go all the way to the peak then, I've seen it done that way many times.:burp::tiphat:
 

bczoom

Super Moderator
Staff member
GOLD Site Supporter
PS. Although the house side is 5/8", why is it needed. The garage is over 50' away from the house. I don't see how 1/8" thicker drywall would make a difference. :confused2:
 

Cowboyjg

Country Club Member
Site Supporter
bczoom said:
PS. Although the house side is 5/8", why is it needed. The garage is over 50' away from the house. I don't see how 1/8" thicker drywall would make a difference. :confused2:



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