How to Finish a Basement Wall or Ceiling Joist

Sand the joist with a fine-grit sanding block. Go with the grain of the wood. There should be no rough surfaces when you are done.

Stain or prime the joist. If staining, use a paint brush and go with the grain of the wood to apply a light coat of the stain. Let this first coat dry for four hours. If priming, brush on a thin coat of latex interior primer. Again, go with the grain of the wood. Let the primer dry for at least four to six hours. If you stained the wood, sand it lightly to rough up the surface and skip the next step.

Paint the joist. Apply a thin coat of latex paint on top of the primer. Let it dry for four hours. Examine the joist. If you see any wood grain or brush marks apply a second coat.

Seal the wood with polyurethane. Apply one coat of non-yellowing polyurethane on top of the wood stain or the paint. This will protect the joist from moisture damage. If you desire a high gloss, let the first coat dry completely, then sand it lightly and apply a second coat of polyurethane.