Finishing
Once your deck is built, it can be stained or sealed immediately, provided it is dry. To select the best finish for your deck, talk with your local building products retailer or paint supplier and follow strictly the finishing directions and recommendations provided by the product manufacturer.
Water-repellent sealer should be applied to all exposed surfaces and ends on your deck as soon as practically possible. (Do not apply if the wood is wet.) The proper application of a good sealer will help protect your deck from weathering and maintain its appearance.
As with any wood, sealer should be reapplied to your cypress deck every one to two years. For best results, a deck cleaner should be used to remove dirt and mildew before any sealer is reapplied.
The best sealing products are those that actually penetrate the wood. Most also contain a moisture inhibitor such as paraffin wax and a binder. Some also contain a pigment to add color to your deck.
When purchasing a sealer, be sure to distinguish between “paintable” sealers, which contain lower concentrations of water repellent (to facilitate the application of paint) and stand-alone sealers, which contain a high percentage of water repellent. Consider using a water-repellent preservative. These products usually contain a mildewicide along with a moisture inhibitor.
If you want to stain to your deck, penetrating transparent or semi-transparent oil-based products formulated especially for decks usually work best. You can use more than one coat as long as subsequent coats are applied while the previous coat is still wet (usually within 30 to 45 minutes). If the stain has already dried, subsequent coats create a film that will eventually produce unsightly cracks in the finish.
Do not use a stain formulated for siding or other horizontal surfaces. Paint or heavily pigmented stains (solid color stains) also are not recommended for your cypress deck.