The Maintenance of Wooden Decks in Cold Climates

Clean Away Debris

• As fall approaches and cooler weather forces you indoors, it becomes easy to forget about your deck. Leaves, pine needles and other debris can build up on your wood deck and these harbor moisture which remains on the wood rather than draining between the boards. To prevent damage, sweep away debris from your deck before temperatures become cold. Cut back trees and bushes that drop excessive amounts of foliage on your deck and use a brush to remove debris caught between the boards. This allows air to circulate properly, which helps prevent the growth of mildew due to prolonged moisture. Continue to sweep away leaves or other material throughout the winter to prevent unnecessary sources of moisture.

Pre-Winter Sealing

• Your wooden deck needs protection from moisture all year. Ice and snow, a constant part of winter in many regions, can pile up on your deck and unprotected wood becomes vulnerable to mildew growth when this thaws. Moisture can lead to cracks and warping of the boards in the spring. Seal your deck with a water-repellant coating in early fall to protect it throughout the winter.

Snow Removal

• Clearing away snow prevents warping and water damage. Use a plastic and not a metal-edge shovel to avoid damaging the boards. Shovel lengthwise along the boards and remove the snow from the deck entirely. Don’t pile it to one side. Shoveling across the boards can result in gouges from the shovel catching the grooves between boards. Whenever possible remove the snow as it falls rather than allowing it to sit on the wood to avoid ice formation as well. Avoid using salt or chemical ice melts. These can discolor or damage wood boards and may remove the water-repellent coatings.

Mildew Control

• Mildew growth is possible during colder months, particularly during wet weather. Mold and mildew stains should be removed as soon as possible and not left to penetrate the wood over the course of the winter. Mix a solution of three parts water to one part oxygen bleach and add 1/4 cup of ammonia-free liquid dish soap in a spray bottle. Spray on the surface of the wood where mildew is present. Allow the solution to sit for about 15 minutes to kill and lift the stain and then rinse the wood clean. If the stain does not fully disappear, reapply the solution and use a soft bristle brush to scrub the wood clean.