- 1). Remove all flooring and any material covering the subfloor until the underlayment is exposed. Pull out any staples from the underlayment that may be left over from carpeting, using end cutting nippers. Unscrew all screws holding the underlayment in place, using a power drill.
- 2). Separate the old underlayment from the subfloor, using a flat pry bar and a hammer, being careful not to damage the subfloor underneath. Inspect your subfloor for damage such as cracks, holes, dips, bulges and any unlevel surfaces.
- 3). Repair all damaged areas before laying down your underlayment. If the subfloor is concrete, patch up any cracks or holes and level out uneven surfaces, using floor patching compound. For a wooden subfloor, cut a square around the damaged area, using a circular saw adjusted so the blade only cuts through the subfloor and not the support beams below. Nail four two-by-four blocks, measured to the size of your square, between the joists under the cut edges of the square for support. Cut a square out of your new piece of subfloor the same size you just removed and fasten it to the top of the blocks you just nailed to the joists of the subfloor, using 2-inch deck screws and a drill, placing each 5 inches apart.
- 4). Lay a full sheet of plywood on the subfloor along the longest wall, ensuring the edges of the underlayment are not aligned with the subfloor seams. Fasten the plywood to the subfloor with 1-inch-thick screws and a power drill every 6 inches along the edge of the plywood and every 8 inches in the center of the plywood. Drive the screw head so that it lies slightly below the surface of the underlayment.
- 5). Lay down the plywood sheets, fastening each sheet to the subfloor, until the entire floor is covered. Ensure the edges of the plywood do not coincide with the seams of the subfloor. Leave a ¼-inch expansion gap between the subfloor and all wall edges. Cut the plywood sheets as needed with the circular saw so they will fit around walls, doorway areas and other obstacles.
- 6). Mix some floor patching compound with the latex additive according to the manufacturer's directions. Use a wallboard knife to spread it over the seams of the subfloor and to fill in the sunken holes made from the screws that attach the underlayment to the subfloor. Allow the patching compound to dry overnight.
- 7). Sand the patching compound, using a power sander. Sweep up the dust left over from sanding, using a broom and vacuum.
- Advertisement -
- Advertisement -