Replies

1. 
   Gene_Davis | Mar 28, 2006 02:25am | #1

   Here is what I have done when installing solid strip wood flooring over a concrete slab.

   Grind off high spots and fill any lows, to get your slab substrate level and flat.

   Take 4x8 sheets of 3/4" CDX plywood and rip each piece lengthwise, yielding two strips about 23-7/8" x 96.  Rip all your needed plywood this way, enough to cover your flooring area.

   Set a circular saw's depth to cut about 1/2" deep, and crosscut kerfs into each ply strip on about 16" centers.  Just eyeball the cuts.  Squareness and spacing isn't important here.  What you are doing is making the plywood substrate nice and flexible so it will lay right down flat.  Plywood can have some curls and cups and bows, and you don't need to fight that.

   Using Bostick's Best one-component moisture-curing urethane adhesive, and a 1/2 x 1/2 square notched trowel, distribute glue on the floor and lay the ply strips into the combed glue, kerf sides down.  Walk on it and use weights where necessary to flatten any places where it won't lay tight.

   Allow 24 hours to cure, then install flooring, per usual method, with either flooring nails or staples, but use fasteners at 1-1/2" length to avoid longer fasteners from bottoming out on your slab surface underneath.