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

Crushed concrete as aggregate under basement concrete slab

bongo30| Posted inGeneral Questionson

Can 3/4 crushed concrete be used under basement concrete slab? The only other option we have is 3/4 bluestone gravel and it’s twice the cost. Thank you.

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

    B30 B30,

    Sure, for the majority of the substrate, but because crushed concrete will take up water much as the slab itself would, you will still need to top dress with a thin layer of stone as a capillary break.

    1. bongo30||#3

      If that’s the case, it probably just makes sense to do all stone instead of crushed concrete. It’s only 4” of aggregate under the slab, doesn’t make any sense to mix both. Thank you!

  2. plumb_bob||#2

    Ask your local inspector. The code I use (BC) requires a clean granular material with no fines, so if the material you are proposing conforms then it may be allowed. In principal I do not see a problem.

Log in or create an account to post an answer.

Community

Recent Questions and Replies

  • |
  • |
  • |
  • |