How to Refinish a Teak Swim Deck

Clean the teak deck using a cleaning mixture composed of 75 percent mild liquid detergent and 25 percent chlorine bleach. Be certain the detergent can be combined with bleach safely. Apply this solution by scrubbing it lightly onto the wood, following the grain, using a non-wire bristle brush. Let the cleaner stand on the wood for several minutes before rinsing thoroughly with water.

Restore the teak's light color, if the basic detergent mixture proves inadequate, using a single-part teak cleaner with oxalic acid. Wet the teak, brush the cleaner onto the wood and let it sit before scrubbing with bronze wool. Use a brush and water to rinse off the cleaner.

Decide whether to apply oil, sealer or varnish to treat the teak. Oil, which should only be applied if varnish has never been applied to the deck, is the least durable wood finish option for teak. The oil only helps recover and maintain the wood's appearance; it doesn't protect the wood. Sealers, which can also be applied to unvarnished teak, are mixtures of oils and polymers or resins that provide another option. Varnishes provide the longest-lasting wood protection of any type of finish. For a deck in the sun, use a spar varnish fortified with UV inhibitors to maintain the teak's color.

Brush oil or sealer onto the clean deck if either of those finishes are being used. No sanding is required for these.

Apply a second coat of oil or sealer to the deck.

Strip, if varnish is the type of finish being used, any old varnish with a cabinet scraper or sandpaper.

Sand the area to be varnished using 220-grit sandpaper.

Brush on the varnish according to the manufacturer's instructions.