# walls or subfloor first



## swimmer_spe (Nov 10, 2016)

I am going to begin finishing my basement. It is concrete block foundation.

I want to put down the interlocking tiles that are wood and plastic; I think they are called dry core subfloor. I then want to put 2x4s along the exterior wall so that I can insulate the room, as well as have space to put in electrical outlets.

Do I put down the subfloor first, then the walls or the walls first then the subfloor?


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## nealtw (Nov 10, 2016)

I would build all the walls firsts but some people do build interior walls on top of drycore.
If you ever do have any kind of flood, the drycore will need to be removed so having walls on top of that just creates another problem.
I wouldn't put it under shower or tub or in the mechanical room.


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## slownsteady (Nov 17, 2016)

Read the dricore installation instructions. Also check YouTube videos from dricore. I remember them addressing this issue.


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## swimmer_spe (Nov 17, 2016)

slownsteady said:


> Read the dricore installation instructions. Also check YouTube videos from dricore. I remember them addressing this issue.



I should have read this:
http://dricore.com/nw/subfloor_faq.php


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## slownsteady (Nov 17, 2016)

Be aware that dri-core is not the absolute best answer. If any moisture collects under the floor, the OSB in Dri-core will mold.


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## swimmer_spe (Nov 17, 2016)

slownsteady said:


> Be aware that dri-core is not the absolute best answer. If any moisture collects under the floor, the OSB in Dri-core will mold.



Is there anything guaranteed not to mold?

The room is the high side of the basement. The drain is at the other side of the basement.
The basement bathroom is located closer to the drain than the room.
The only water related thing in the room is the water meter. 

The floor so far as been dry since I moved in in June. I will watch in the spring to see if the room has any seepage


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## Sparky617 (Nov 18, 2016)

Ceramic tile won't mold, but it is cold.


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## nealtw (Nov 18, 2016)

The question is all about the water proofing and drainage on the outside that protects the basement from leaks.
No body wants to dig that up just to check and it is really hard to judge where in the lifespan of those systems you are..
Even when those systems are working fine the bottom of the footing could be in wet areas and water will wick up thru concrete toward warm and that is why we want some concrete showing on the outside between the ground and the siding.
So when you build walls inside they don't want to touch the concrete and insulation will keep the inside of the foundation cool so wicking is not a problem.
You want a vapour barrier behind the drywall so warm moist air from the living space does not get to the cavity.

Then when you build that outside wall with a 1" cavity behind it the top of the cavity wants to be blocked on the top for fire stopping. This part always sounds hard but it is the easy part and really helps with keeping the rooms in the basement square.


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