Better bolster those loose stairs

Q: I returned home from a business trip last week and, walking up the stairs, one of the steps actually lifted up from the back as I put my foot on it, then flopped back into place as I continued up. I put some wood glue along the back edge and tapped it tight against the vertical board behind it, but it has come loose again. Any tips? — Edward F., via e-mail

A: If you can access the underside of the stairs, place sturdy screws through the riser (the vertical board between each step) and into the back of the step to make sure it stays in place. Many staircases are enclosed, however, so you’ll have to make the repair from the topside.

•I’d recommend inspecting the step closely before securing it to make sure it’s not damaged. If you can pull the step away from the riser and stringers (the vertical bracing on either side of the step) without damaging the wood, do so. (A pry bar and hammer are helpful.)

•Inspect all surrounding wood for damage and scrape away old glue and paint from the contact surfaces.

•If the step is damaged — cracked, broken or rotted — it should be replaced; measure and cut a new tread to size and test fit. If it’s not damaged, remove old nails and test fit.

•Apply a bead of construction adhesive along the tops of the stringers, and set the step in place. To fasten it from the topside, drill pilot holes through the tread into the tops of the stringers (two or three each side) and drive screws through them. Countersink the screws and fill the holes with wood putty or plugs.