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

Barn Basement

Alexander Lane | Posted in General Questions on

Hello all, I am trying to put a floor in the basement of my barn in Western Mass., and would like to outline my plan and get thoughts on whether it seems sensible. I’m trying to make a workshop down there. Not trying to meet any code here, just going for somewhat comfortable and durable. 

It is a fieldstone foundation with good concrete footings underneath. Right now there is a dirt floor. Occasionally the soil seems a little damp. Having a slab poured was too pricey ($3,600).

I plan to:
-Dig down a bit more for more headroom
-Slope the dirt slightly to the outside edges
-Put a trench around the edges sloped to a hole in one corner
-Put down polyethylene
-Put a perforated pipe in the trench that leads to a 5-gallon bucket in the hole
-Cover all that with a few inches of gravel
-Put PT 2x4s on edge on top of the gravel, 16″ on center
-Rigid foam between the 2x4s, spray foam around the edges
-Lay a plywood floor on the 2x4s

If the bucket fills with water I’ll put a sump pump in it emptying to a dry well outside.

What do you think?

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.

Replies

  1. Expert Member
    Malcolm Taylor | | #1

    Alexander,

    I'd suggest a slight variant on what you are proposing.
    - Compact the gravel
    - Cover with poly (keeping the poly above the gravel allows it to act as a capillary break).
    - Lay a layer of continuous rigid foam.
    - Either PT 2"x4"s on the flat with a plywood sub-floor.
    - Or 2 layers of sub-floor on the foam.

    https://www.greenbuildingadvisor.com/article/the-concrete-free-floating-plywood-slab-assembly
    https://www.greenbuildingadvisor.com/article/another-take-on-a-concrete-free-slab

Log in or create an account to post an answer.

Community

Recent Questions and Replies

  • |
  • |
  • |
  • |