Can Snow Ruin a Wood Deck?

Weight of Heavy Snow

• Most decks are designed -- and required -- to hold 40 or 50 pounds per square foot. But this is not necessarily true of older decks that were built before building codes changed; or decks not built to code, such as those put together by a homeowner or unlicensed handyman. Just as with roofs, homeowners should remove wet, heavy snow -- known as "snow load" -- from decks to prevent undue strain on floorboards or the underneath supports. This should be done immediately after a heavy snow -- such as dropped in blizzard conditions -- in areas that do not experience heavy snowfall as a norm. In colder climates where heavy snowfall occurs regularly, snow removal should be done continually; this can prevent damage that accrues slowly over a winter of continual heavy snow.

Melting and Refreezing Snow

• As snow melts, it can be absorbed into the wooden boards on the deck. These can swell with the water; a refreezing can then cause them to crack and split. Melting snow then enters the damaged wood and causes increased exposure with additional refreezing. Basically, it's a continual process that eventually will destroy the deck. Maintaining a water-resistant sealer and pressure-treated wood provides some protection. Removing snow before it can melt and refreeze also provides protection. For light, feathery snow, a broom can be used to brush it off the deck.

Snow Removal

• Homeowners can accidentally damage decks in an attempt to protect them from ice and heavy snow. Ice melters and winter salts should never be used on a wooden deck. In addition to damaging the wood, these products can remove the protective sealer and stain or discolor the deck. Do not use a metal shovel; the steel can catch on the wood and create cracks and chips, allowing further winter damage. Instead, use a plastic shovel, running it parallel to the boards rather than raking it across them when removing snow.

Acid Spring Shock

• Acid snow is created as the water in the atmosphere picks up gases and particles, changing the acidity of the water. Although snow tends to be less acidic than plain rainwater, it places those acidic particles onto -- and into -- wooden deck boards as it melts. This is especially prevalent in the spring, when sudden melting provides a large rush of acid water over the deck. Although the phenomenon was first noticed in the 1980s in relation to aquatic life being affected by spring melt, homeowners now experience damage as the large acid rain concentration in piles of snow melts and makes contact with decking. The acidity level can be high enough to eat through automobile paint; decks with cracks and splits from wear and tear, or melting and refreezing snow, are especially vulnerable to additional damage.