How to Attach a Wood Sill to a Concrete Slab

Place layout marks on the concrete slab by snapping lines with a chalk box. Place the wood sill flat onto the concrete slab. Adjust the wood sill until it is in the spot where it will be secured to the concrete.

Measure 6 inches in from the butt end of the sill plate and place a mark where you'll drill the first hole. Measure every 16 inches from the first mark across the entire sill plate, making sure to stagger the marks slightly from edge to edge; this will prevent the sill from bowing and splitting when the anchor bolts are inserted.

Prep your hammer drill by inserting a masonry bit, which should be slightly longer than the anchor bolt, into the chuck and locking it in place.

Drill through the wood sill and directly into the concrete slab with the hammer drill until the drill's chuck reaches the face of the wood sill. Plunge the spinning masonry bit up and down into the hole to remove debris and dust. Use compressed air to remove any remaining dust and debris from the hole.

Slip a concrete anchor bolt into the drilled hole and tap the back of it with a hammer until it is fully seated inside the hole. Attach a ratchet to the nut of the anchor and rotate it clockwise to engage the expanding sleeve inside the hole.

Repeat this process with each layout mark on the sill, working your way across the entire wood sill. Make sure that the sill stays inside the layout marks that you made on the concrete slab. Manipulate the sill, as needed, by pushing the unsecured end left or right before drilling.