Installing drywall over concrete basement walls


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Old 01-13-16, 06:25 AM
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Installing drywall over concrete basement walls

Hi!

I'm putting up drywall on my basement walls. They are made of cinderblock. I plan on installing 1" metal studs, rigid board insulation, and 1/2" drywall on top of that. My problem is that I need drywall screws no deeper than 1.5" (1" really) so that it won't go through the cinderblock. Where can I find 1.5" or less drywall screws? HD or Lowes don't seem to carry them and a google search came up empty for me too.

Thanks!
 
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Old 01-13-16, 07:52 AM
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Unless this space is for storage you will need to install outlets at least every 12' or wall space. 1" of stud space in not enough for anything other then a handy box which you can only fit a few wires.

1 1/4" fine thread drywall screws should work fine/ You will be attaching 1/2" rock which means only 3/4" of screw will penetrate the stud. Grip-Rite #6 x 1-1/4 in. Philips Bugle-Head Fine Thread Drywall Screws (5 lb.-Pack)-114DWS5 - The Home Depot
 
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Old 01-13-16, 08:10 AM
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.... and it's best to have an air gap between the framing and the foundation wall.
 
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Old 01-13-16, 10:10 AM
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Thank you for your messages. Based on what I am reading it looks like i should furr out the wall more than an 1 - maybe an 1-1/4 or 1-1/2 so that there is room for the electrical outlets. This will let me use 1-1/4" screws. Thanks for the advice!
 
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Old 01-13-16, 11:34 AM
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I disagree with the air gap. You dont have to have your framing touching the cinderblock, but there must not be any open space between the block and insulation for air to circulate. Ideally your rigid insulation would go against the block, then your framework in front of that with batt insulation.

You can also get foam sheet insulation that is already grooved out to accept a 1x3. nail or screw the 1x3 over the foam and into the foundation and you have a ready made surface to hang drywall.
 
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Old 01-13-16, 11:46 AM
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If this wall is below grade it should have a few inches of air gap. This is so the wall can dry out. No air gap and your interior wall will wick up the moisture from the block wall. If above grade it can dry from the other side.
 
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Old 01-13-16, 11:49 AM
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I'm a painter not a carpenter but the way I usually see it done is a stud wall is erected in basements set just off of the foundation wall. When it's above grade they normally fasten furring strips to the block wall .... never paid a lot of attention to how the electrical was run when furring strips were used.
 
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Old 01-13-16, 12:01 PM
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This is why a vapour barrier is necessary against the wall but only below the grade level. Foam insulation will act as your vapour barrier, otherwise you need plastic on the wall. It only goes to grade level so moisture can dry to the outside of the exposed wall.

The problem with the air gap is it will lead to convection currents behind the wall reducing insulation value and leading to condensation.

MYTH: LEAVE AN AIR SPACE BEHIND THE INSULATION IN THE BASEMENT TO AVOID CONDENSATION.
 
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Old 01-13-16, 12:15 PM
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Keep in mind that a space between the concrete wall and the stud wall may be necessary due to variations in the concrete wall.
 
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Old 01-13-16, 12:23 PM
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You are right stickshift, but that space must be kept to a minimum. if your studs are more than 1/2" from the wall, you should cut insulation to fit between the studs and wall, or better yet sprayfoam the gap.
 
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Old 01-13-16, 12:28 PM
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that space must be kept to a minimum
Absolutely. Thanks for clarifying something I left out, Keith
 
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Old 01-13-16, 01:35 PM
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A VB on a block wall below grade will cause moisture issues because the block can not dry out.
 
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Old 01-13-16, 01:53 PM
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A block wall does not wick moisture through the wall the same way a solid concrete wall does and is much less of an issue. Regardless, any moisture that does come through can still dry to the top of the wall.

Basement walls -- Moisture & Vapour Barriers

Having said that, if you have water running through a block wall to the inside, that is a different issue and needs to be addressed before it is covered up.
 
 

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