View Single Post
Unread 01-16-2019, 04:25 PM   #4
Veteran DIYer- Schluterville Graduate

STAR Senior Contributor

Join Date: Jul 2004
Location: Nashua, NH
Posts: 14,076
There are two components of deflection...
- along the joists...doesn't really matter what's on top (within reason) that number is critical
- in between the joints. This is where extra plywood may come into play. The minimum depends on the joist spacing and the ply thickness.

Both must meet industry standards. It's easier to fix a between the joist deflection issue than along the joists, since it can all be done from the top.
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 online now   Reply With Quote