View Single Post
Unread 10-23-2020, 02:21 PM   #2
jadnashua
Veteran DIYer- Schluterville Graduate

STAR Senior Contributor

 
Join Date: Jul 2004
Location: Nashua, NH
Posts: 14,202
You need at least 1/2" of ply. TO keep the buildup lower, you could go with a membrane versus a cbu product. FWIW, planks just move too much, and you need something more substantial than cbu on top of them for stability.

Have you checked your floor joists for strength? Are the planks T&G?
__________________
Jim DeBruycker
Not a pro, multiple Schluter Workshops (Schluterville and 2013 and 2014 at Schluter Headquarters), Mapei Training 2014, Laticrete Workshop 2014, Custom Building Products Workshop 2015, and Longtime Forum Participant.
jadnashua is offline   Reply With Quote