Flooring-grade particle board (also known as chipboard) is usually made with tongue-and-groove edges, including the board’s shorter sides. Supporting blocking should be placed around the room’s perimeter.
Position the first board across the joists. Insert wedges between the board and the wall, to create an expansion gap of 3/8" (image 1).
Screw the board in place, using particle board screws. These should be inserted at 6-inch intervals, positioned along a joist (image 2).
Apply wood glue along the tongue of the board. Then slot the next board in place (image 3).
To create a tight joint, tap the boards in place, using a scrap piece of particle board as a knocking block (image 4).
As you tighten the boards, you will probably need to wipe away excess glue with a damp sponge.
Continue to lay the particle board. At the edge of the room, mark and cut the boards to fit the remaining space and fix them with screws (image 5).