As my kitchen subfloor (T&G planks, 3/4 inch) had water damage and other general damage, I decided to replace it. I cut it flush with the wall, and will soon be ready to replace it with plywood (T&G, 3/4 inch) plywood. I kept reading that you always need 1/4 " expansion gap around perimeter and 1/8" in-field.
A) Do I need that gap in the perimeter for subfloor?
B) If yes, then pbly do I need support underneath subfloor along the wall (which are perpendicular to joists)?
My thinking right now is to have support under wall edge, leave 1/4" gap then fill it with caulk or other flexible materials.
Then I plan 1/2" plywood (staggered) also with 1/4 inch gap on perimeter
Then radiant floor then ditra then tile...