Can You Leave Snow on the Deck?

Before we get to the topic at hand, permit me a personal admission: I don’t leave snow on any walking or driving surface, at least not for long. I’m the guy in the neighborhood with the extra wide shovel, clearing the sidewalk at my end of the block before dawn so early walkers don’t pack down the snow.

After one late spring snowstorm, I wanted to burn off the gas in my snow blower so it wouldn’t go stale over the summer. I blew my walk and drive, then that of one neighbor, then another, on and on around the corner. When my blower finally ran out of gas, a neighbor thanked me and added, “Are you running for office?”

Decks are the one exception to my snow-clearing sensibilities. They’re increasingly built with composite materials that are low maintenance. Why add to your shoveling duties by clearing the deck? Composite boards can take whatever winter dishes out, right?

Let’s find out.

Can You Leave Snow on the Deck?

Of course, you can leave snow on your deck. But should you? No, says Vince Christofora, an engineer and owner of Woodstock Hardware in Woodstock, New York.

Here are three reasons why you should remove at least some snow from your deck.

Weight damage

“Decks, like roofs, should be designed to handle snow loads for the areas in which they are built,” says Christofora. “Footings and the structure of the deck should be sized accordingly. If you let snow pile up on your deck and have an undersized or not well-designed deck, you should be concerned about the weight, just as you would be with a roof.”

Consider the math. Christofora says concrete weighs 150 pounds per cubic foot; dirt and gravel 110 pounds; and snow 15 to 20 pounds. “It’s not necessarily fluffy stuff, especially when it builds up,” he says. “Removing snow even after a lighter storm helps, and allows you to be ready in case there is an unexpected mega-storm.”

Damage to deck boards

Water in any form that covers deck boards is never good over time.

“Leaving snow on the deck can shorten the life of your deck coating because there’s water sitting on it non-stop,” Christofora says. “One of the best things you can do is make sure your deck has a good coat of stain, paint or sealant on it before the winter season arrives.”

Christofora says he still sees a lot of wood decks in the Northeast. “We don’t see as many pressure-treated decks as we do cedar, mahogany and exotic woods, which are expensive,” he says.

“The general consensus is maintenance-free is not really maintenance-free. They get dirty and moldy, and you need to clean them like a regular deck. Now they make stains and waterproofers that you can use on composite wood decks.”

Safety in an emergency

A deck clear of snow may save a life in an emergency.

“You don’t know when a rescue squad might need to come up the deck stairs with a stretcher to get somebody who’s hurt out of the house,” says Christofora. “What if there’s a fire? It’s dangerous getting out of the house when the deck is covered with snow or slippery because of the snow.”

Removing Snow from a Deck

When removing snow and ice, Christofora suggests following the same guidelines whether it’s wood or composite. Tools or products to use include:

Plastic shovel

“To avoid damaging — scratching, gouging, etc., — a wood/composite deck, use a plastic snow shovel, not a metal one, and make sure the plastic shovel does not have a metal edge,” Christofora says. Shovel parallel to the boards, and leave a thin layer of snow so you don’t damage the surface.

To provide traction without melting the ice, use sand or a non-toxic product like Ecotraction. “There are non-slip tape/treads you can use for traction, but they may freeze up and become slippery in winter weather conditions,” he says.

Electric snow thrower or small snow blower

These are light enough for low decks. Be careful not to damage the surface.

Ice melter

Avoid rock salt or calcium chloride, Christofora says. Choose an effective, more environmentally friendly ice melt blend like SafeStep 6300 magnesium and potassium chloride.

“Whatever you use, to avoid damaging the deck surface, sweep off the product after the product has done its job, within a day or so,” Christofora says.

Ice Chopper

“In extreme conditions, if you are going to use a metal ice chopper, be careful not to damage the deck,” says Christofora. “Chopping can get out of hand.”