Exterior Wood Care for Pressure-Treated Lumber

By Matt Weber

Staining and Sealing to Fight Mother Nature.

The natural beauty, durability and affordability of wood are what keep pressure-treated lumber at the top of the list of materials for decking and outdoor projects. However, all outdoor wood, including cedar, cypress and even hardwoods, should be well maintained and protected from weather to ensure a long life and top-notch performance. In this article, EHT takes a new look at some of the basics of exterior wood care and how to get the most from you topcoats.

Clean Start

Staining and sealing your deck is one of the best ways to protect your investment from the elements. Start with proper cleaning and preparation. First, inspect the entire area for bad wood-not just the deck boards. Check the steps and handrail system for dry rot, loose balusters and broken boards.  Replace damaged pieces and secure any loose fasteners or balusters.

To simply remove dirt and grime, there is a wide range of wood-cleaning products on the market. To renew the appearance of previously coated surfaces, use a more aggressive deck stripper. Stripping is also important when changing colors, because leftover traces of an old pigment can affect the way a new color appears. Both cleaners and strippers brighten wood surfaces that have dulled and grayed from sun, dirt and rain exposure. When applying, wear gloves, safety glasses and disposable clothing. Before starting, cover any areas you want to protect, wet down plants and shrubs, and wet your deck surface with water.

Mix the product and apply it according to the manufacturer’s instructions. Applying with a roller mounted to extension handles usually works well. Work the chemical into the wood grain. For vertical surfaces, this can be accomplished with synthetic brushes (2 to 4 inches). Keep the surface damp with water and let the product agitate the wood surface for 20 to 30 minutes before rinsing.

The deck-cleaning solution may be followed by power washing at 500 PSI- but be careful. Too much pressure can cause the power washer to damage the wood, causing the surface to “fuzz.” Use only a low-pressure nozzle and work the water stream with the grain and never against it, which can cut into the surface. Once cleaned, let the wood dry for at least 48 hours before applying stain. A properly cleaned deck should be stained within 30 days. After 30 days, a light cleaning with bleach and water before staining will do the trick.