How to Anchor Wood Stairs to a Concrete Floor

Drill four evenly spaced holes across the top of the anchor plate, secured between the left and right stringer. Drill the holes large enough to accommodate the threaded shafts on anchor sleeve bolts.

Position the staircase and mark the holes you drilled into the anchor plate onto the concrete floor. If possible, remove the staircase while you work. Otherwise, prop the staircase off the floor so you can access the concrete floor with a drill. Drill holes at each marked location using a masonry drill bit with the same diameter as the concrete anchor sleeves. Use the hammer drill to drill the holes approximately ½ inch deeper than the length of the anchor sleeve bolts. Vacuum the debris from the holes with a vacuum cleaner or use compressed air.

Drive the concrete sleeve anchors into the concrete, using a rubber mallet, until the top of the sleeves rest flush with the surface of the concrete. Position the stairs over the anchors, lining up the holes in the anchor plate with the anchors in the concrete floor. Thread the anchor sleeve bolts into the anchors and tighten them with a socket and ratchet.