Deck Sanding Tips

Sand the deck in preparation for refinishing.

Decks define outdoor living spaces. Your deck offers a centralized spot for entertaining, but if its paint is peeling, or if the wood is rough and splintering, it can detract from the deck's ambience. Sanding the wood will remove old paint and rough spots, enabling you to refinish the deck. Minimize your labor and speed the sanding process with some deck sanding tips.

Clean and Prep the Deck First

Before you sand, wash the deck with trisodium phosphate to remove body oils, greasy spots and grunge from the wood. Mix the TSP, available at hardware stores, with water as directed on the container, and sponge it onto the deck, scrubbing with a stiff-bristle brush. Rinse the deck off with a water hose, and let it dry completely. Countersink any nails or screws that extend above the decking surface before sanding. Just one nail head can tear up a sanding disk.

Power Up

Sanding by hand is time-consuming and labor-intensive, but you can rent an upright deck sander that will cut sanding time. A random orbital sander, fitted with 80-grit sandpaper, will sand off the old decking surface without making cross-sanding marks in the grain. To reach beneath the bottom railing and between balusters, use a vibrating hand sander with a long, flat sanding attachment. The vibrating sander also works well on the top of the railing and on the flat surfaces of square balusters.

Use the Right Grit

Sandpaper and sanding disks come in grit sizes that offer different sanding effects. An 80-grit removes old paint and smooths rough grain, but it's too aggressive for finish sanding. Switch to 120-grit and sand the deck again before applying a sealer or paint.

Considerations

If your deck's in sorry shape, forgo the random orbital sander and opt for a small hand-held vibrating sander. Years of exposure to the elements can cause decking to "cup," making the sides of the planks warp upward. When this occurs, a large power sander can't adequately reach the lower wood surfaces.

If most of the decking is in good shape, but one or more planks are badly damaged, replace those planks before sanding.

References

• Deck Doctor: How Do I Sand a Deck?
• Orbital Sander Review: Different Types of Sanders