GBA Logo horizontal Facebook LinkedIn Email Pinterest Twitter Instagram YouTube Icon Navigation Search Icon Main Search Icon Video Play Icon Plus Icon Minus Icon Picture icon Hamburger Icon Close Icon Sorted

Community and Q&A

Finished Basement Floor Insulation

nynick | Posted in Energy Efficiency and Durability on

We’re planning to finish the basement in our old house during the overall renovation. As I’ve mentioned before, we’re looking to have 2″ of Closed cell sprayed on the walls behind 2×4’s located 2 inches away from the walls and put no insulation in the ceiling. The basement floor slab is uninsulated.
While the architect was here the other day she suggested laying some PT 2×4’s flat on the concrete floor, laying 1 or 2 inch foam boards down and then laying plywood and flooring down so the floor doesn’t feel cold.
We’ll be using this area sporadically, maybe as a TV or Rec room, but not as daily living space. Since all the mechanicals will also be down there, it’ll be simple to condition this space and we had planned to anyway.
Do I need to build an insulated floor down there?

GBA Prime

Join the leading community of building science experts

Become a GBA Prime member and get instant access to the latest developments in green building, research, and reports from the field.


  1. jadziedzic | | #1

    I finished my basement some twenty-odd years ago and did not install any sort of insulated floor. We had glued-down commercial grade carpet installed in the game room and we don't notice any coldness through the carpet. There are no water leaks into our basement so I was comfortable with the glue-down method. If your basement slab is damp maybe consider something like the Dri-Core panels with a finished floor on top of that.

    Keep in mind if you install 2x4 sleepers and something like 3/4 plywood or Advantech the first step up from the (now higher) basement floor will be a couple of inches shorter than the remaining steps, which is both a safety hazard and a building code violation (the maximum allowable height difference between adjacent treads is 3/8"). That difference in "cadence" is especially noticeable when coming down the stairs and can cause tripping.

Log in or create an account to post an answer.


Recent Questions and Replies

  • |
  • |
  • |
  • |