Solid hardwood strip flooring installed over a wood subfloor at grade needs an expansion allowance. At the walls, the installer should:

Giải thích

Wood flooring expands and contracts with humidity, so a small perimeter expansion gap (often roughly equal to the board thickness) is left and concealed by baseboard and shoe molding. Butting tight causes buckling, a 2-inch mortar-filled gap is wrong, and gluing ends to the wall prevents needed movement.