How to Install Wood Sills on Concrete

A sill plate is a piece of 2-by-4 or other-sized lumber attached to a foundation pad, usually concrete or block. Studs are then nailed to the sill plate to create the framing for walls. When installing a sill plate directly to concrete, you must use the proper fasteners to keep the sill permanently attached. Simply screwing into concrete will not yield a proper connection between the sill and the concrete surface.

Things You'll Need

• Hand drill
• 1/4-inch carbide drill bit
• Nail
• Hammer
• Hammer drill
• 3/16-inch carbide drill bit
• 1/4-inch-diameter, 4-inch-long concrete screws
• Screwdriver

Instructions

1. Drill a hole though the wide face of the board you plan to use as the sill plate approximately every 12 inches with a hand drill and 1/4-inch drill bit.

2. Place the board onto the concrete and mark each mounting hole onto the concrete surface with a nail. To do this, place the nail in the 1/4-inch hole and strike the nail with a hammer to leave a mark. Do this with each hole. Place the sill plate off to the side.

3. Drill a hole 1/2 inch deeper than the screw will go into the concrete with a hammer drill and a 3/16-inch drill bit. For example, if you use 4-inch-long concrete screws and your sill plate is 2 inches thick, drill the holes 2 1/2 inches deep.

4. Place the sill plate over the holes in the concrete and place the concrete screws into the holes in the board.

5. Drive the screws into the concrete with a screwdriver.

References

• Confast: How to Install a Concrete Screw