Replies

1. 
   BrianPontolilo | Dec 02, 2018 08:41am | #1

   I've seen it done both ways. When the wall's bottom plates are on the concrete floor, they are usually pressure treated and I have seen builders use sill seal as a thermal break when installing plates on basement floors. That said, I'm not sure why partition walls shouldn't just be installed on top of the subfloor. Without any significant load, I can't see them compressing the floor system and pulling away from the framing they are attached to above.

   I bet you'll get some more thoughts on this. In the meantime, here are some articles that may be helpful with your basement remodel:

   https://www.greenbuildingadvisor.com/article/all-about-basements

   https://www.finehomebuilding.com/2014/11/05/build-a-risk-free-finished-basement

2. 
   gdunkle | Dec 02, 2018 10:43am | #2

   Thanks, Brian! Yeah, both ways seemed reasonable to me, but I didn't know if there was a consensus on which was the best practice.

   Thanks also for the article links. They led me to:
   https://www.greenbuildingadvisor.com/article/how-to-insulate-a-basement-wall

   Which set me straight on interior basement insulation not needing to be vapor-permeable. I didn't realize the thinking on this had changed. Now, I'm wondering if I should go with Thermasheath Rmax Polyisocyanurate Rigid Foam Insulation Board rather than Kingspan Insulation Unfaced Polystyrene Foam Board Insulation?

1. Expert Member
   MALCOLM TAYLOR | Dec 02, 2018 04:01pm | #3

   gdunkle,

   There are a few good reasons to put the walls on top of the subfloor.

   - Makes installing the foam and plywood a lot easier. Much less cutting and waste.
   - Keeps the bottom-plate high enough to provide backing for trim.
   - Securing the walls to the subfloor doesn't involve drilling into the slab.
   - if you ever decide to renovate, moving the walls is a lot easier

3. 
   gdunkle | Dec 02, 2018 06:13pm | #4

   Excellent points. Thanks, Malcolm.