Should I Get an Orbital Sander for My Deck Refinish?

Sanding Decks

• Refinishing a deck involves removing the old finish and smoothing the wood grain before applying the new finish. Soft woods, such as redwood and cedar, may require only a light sanding to remove the weathered surface and reveal new-looking wood beneath. Treated wood decking may require additional sanding. Orbital sanders come in small hand-held models and large floor models. A floor model is the best choice for flat decking, but you’ll need a hand-held model for the railing cap. If you have balusters, sand those by hand.

When to Use an Orbital Sander

• When the deck planking is relatively flat and smooth, an orbital sander is a good choice. An orbital sander features a disk that vibrates rapidly in a circular motion and a disk head that vibrates in a back-and-forth motion. The combination of these motions reduces the risk of the sander leaving scratches on the decking.

When Not to Use an Orbital Sander

• If the decking planks are cupping, meaning the edges of the planks are heaving upward, an orbital sander might not be the best choice. In this case, the sanding disk makes contact only with the raised edges of the planks, making it difficult to control an orbital sander, which tends to slide or bounce. In this situation, sand softwood planks by hand, or rent a walk-behind drum sander to grind away the high edges of harder woods.

The Process

• Before you start sanding, prep the deck surface. If you use a deck stripping solution, make sure the wood is completely dry before sanding. Use a hammer and nail set to countersink nails that have worked out of the decking or a drill to countersink screws. Start by attaching a coarse-grit sanding disk to the sander, and switch to a fine-grit disk for subsequent sanding passes. Follow all the safety instructions that came with a power sander.