Building A Subfloor

Materials:

builder's transit
broom
measuring tape
6-millimeter plastic sheeting
utility knife
hammer stapler
pressure treated 2x4s
pressure treated 2x6s
safety glasses
dust mask
ear protection
pneumatic nailer
16-penney nails
stud finder
subfloor adhesive
insulation
chalk line
sledgehammer
circular saw
4x8 sheets of plywood flooring
caulking gun
subfloor adhesive
T-square
2-1/2 inch screws
screw gun
baseboard trim
finishing nails
hammer
carpet knife
carpet
carpet padding

1. Use a builder's transit to check the floor for level (figure A). If it's level, begin building your subfloor. Remove the baseboards remaining along the wall and then sweep off the floor to remove any debris.

2. Lay down a 6-millimeter sheet of plastic on top of the slab to act as a vapor barrier. Use a utility knife to cut the plastic to size and secure it to the bottom of the wall with staples.

4. Use a stud finder to locate the studs and then drive 16-penney nails through the 2x6 band and into the studs. Cut joists to length and attach to the outer band by toenailing them into the 2x6s with 16-penney nails (figure C). Continue working along the length of the room until all of the joists are installed and the floor framing is completed.

5. Place insulation between the joists, keeping the paper side up and being sure not to compress the insulation (figure D). Cut the insulation with a utility knife. Wear long sleeves, a dust mask and eye protection whenever you work with insulation.

6. Measure out 4-feet from a corner and snap a chalk line across the joints to ensure you keep plywood straight during installation. Apply the subfloor adhesive to the joists using a caulk gun. Put the first 4x8 sheet of plywood in place, line it up with the chalk line, then use a T-square to make a straight line along the top of the plywood to mark the location of the joists (figure E).

7. Use a screw gun to secure the plywood to the joists with 2-1/2 inch screws (figure F). Continue the same process with the rest of the plywood, applying glue to all of the joists and securing the plywood with screws. Be sure to stagger your joints. Use a sledgehammer and a scrap piece of 2x6 to help push the pieces of plywood together and insure that you have a snug fit. Cut plywood to fit using a circular saw.

9. Nail tack strips with the teeth inclined toward the wall to the plywood subfloor. Start in a corner. Be sure to leave about a 1/2-inch gap between the strip and the wall (figure H).

10. Install carpeting. First roll out the padding and cut it to width using the carpet knife. Leave the padding an even distance from the tack strips (figure I). Attach the pad to the floor using a hammer stapler.

11. Roll the carpet out overlapping the walls about two inches around the perimeter of the room. Use a carpet stretcher to hook the carpet over the tack strips (figure J).

12. Make sure the carpet is well seated on the tack strips then stretch and tuck it under the baseboards. Cut away excess carpet along the wall and continue tucking the carpet under baseboards with a stair tool.