Will Ice Damage your Deck this Winter?

Some guys like ice.

Ice can be fun.

Do you like ice?  I like ice…in its place.  In an Olympic rink, ice can propel a figure skater to a spectacular performance.  On hot August day, ice can transform a Coke from nice to wonderfully refreshing.  I like ice.  But not on my front steps.  Or on my backyard deck.

Ice can make you fall and can hurt you.  And ice is sneaky.  It hides under snow, so you do not see it.  You’re just walking along a snowy sidewalk and WHAM!  You’re on your ***.

Ice can hide in plain sight.  On roads in the northeast we call it black ice, but it is not black, it is clear — and the dark asphalt shows through.  So the road looks clear and safe.  But really the road is clear and dangerous.  With catastrophic results.

Ice on your deck threatens to injure you and your family.  Would you walk down these steps? 

Ice can hurt you, but can ice hurt your deck?

Yes, indirectly.
Ice frozen on your deck floor will not damage the wood or a plastic surface.  Ice will not rot you deck.  But, as I said, ice is sneaky.  It may trick you into damaging the deck yourself.  Perhaps your daughter tries to fetch a toy on your deck, and she falls on the ice.  You want some revenge…chop that ice into harmless little pieces.  Wait.  Do not attack ice with a steel shovel or some other sharp implement.  You will gouge the wooden floor boards or dent that beautiful low-maintenance surface.  Instead just spread some calcium chloride to melt it away.  Or, if you can wait, let Mother Nature remove it in the spring.  Mother put that ice on your deck, let her remove it.

Can ice damage your deck in other ways?  Well, yes.

Remember last winter?  Record cold and record snow.  Massive snow falling from some roofs badly damaged and even destroyed some decks — you saw that in my article about snow on decks.  But ice?  Ice is more insidious than snow.  It doesn’t need “massive” to cause havoc.  Mother skillfully crafts ice into heavy weapons.  Then she sharpens them so they can cut and pierce.  Icicles.  You remember icicles — those shiny, iconic symbols of winter.  She forms icicles at the edge of your roof, builds them bigger, sharpens them, and then aims them at your deck below.

Why sharpen the icicles?  To concentrate the force.  Remember your physics?  Force = Mass x Acceleration.   Well, Mother Nature wrote the book of physics.  She knows that if she spreads an icicle’s weight over, say, 12 square inches, it will not break a deck board when it falls.  But sharpen that icicle’s point to one square inch, and it will puncture your floor.  So Mother builds up the weight of selected ice daggers, and when they are big enough and sharp enough, she drops them.  And pokes holes in your deck.  Here’s some icicle damage before we repaired it last year.

So what can you do?  Hang out a second floor window and break the icicles with a broom stick before they damage your deck.  Really, a broom stick? Just whom do you think you are dealing with here?  You’ll reach way out to get that big icicle, and Mother will pull you out the window.  No, you won’t fool Mother Nature.   She’ll just move over another foot, beyond the reach of your foolish broom stick, build a bigger icicle, and then drop it.  I think Mother does this for laughs.

You could put some big wood planks, like 2×10 planks, over your deck boards to protect them from icicles above.  That might absorb the icicle’s weight, spread it out, and perhaps save your deck floor.  Estimate where Mother is aiming before you place your planks.  Just don’t estimate badly.  Of course, Mother may add some wind when she drops that icicle, just to mess with you.  OK, then try plywood.  Wide sheets of thick plywood.  That might work.  (I think someone is laughing at you.)

Icicles falling from a first floor roof will not break your deck.  They need more height.  Remember the acceleration in F=M*A.   The point of an icicle falling six feet from a first floor roof cannot gain enough acceleration to puncture a floor board.  But second floor icicles falling 15 feet can.  They are dangerous.

Is that all?

Almost.  Besides being sneaky, ice can be patient.  Consider the posts on concrete footings that support a deck.  Some deck builders insert their wood posts into the concrete before it hardens.  That’s a strong connection, right?  Embed the post several inches into the concrete — it’s solid, and you don’t need one of those metal brackets.

For a while.  (Chuckle)  To avoid rot, deck support posts are made of pressure treated wood.  Well, PT shrinks as it dries.  Slowly, over many months.  But concrete takes its final shape in a day or so.   So the PT post shrinks and opens a gap between it and the concrete.   The gap may seem small — a quarter of an inch or perhaps a half — but Mother does not need much.  During autumn, she fills the gap with rain water and then waits.  Mother is patient.  In time winter cold freezes the water into ice.  The ice expands and breaks the concrete footing.

“Fantasy” you say.  Can’t happen.  Heat expands, and cold contracts.  Everyone knows that — right?  Well, it turns out that there’s some fine print in that particular Law of Nature.  As water freezes, it expands.  Really.  That’s why icebergs float.  As they freeze, they expand, become less dense, and weigh less than the volume of water they displace. The expanded ice is buoyant and floats.¹

Still skeptical?  Here’s some deck footings in Lexington that Mother played with.  We replaced the entire deck.

So ice can damage your deck.  But don’t battle Mother Nature, join her. 

NOTES:

1. For a detailed explanation of ice expansion, see this brief, authoritative article.
2. And by the way, LL Bean sells little crampons that fit over your boots and allow you to walk safely on that icy driveway.  Conquer ice for just 30 bucks.

We at Archadeck of Suburban Boston offer professional design and build services for clients west and north of Boston.  Over the past 26 years we have designed and built over 950 projects.  We have enhanced the depth of our expertise by limiting our work to decks, porches, sunrooms, and patios.  To view some of these projects, visit our website. To learn how we treat our clients, check us on Angie’s List or read a recent article about us in Remodeling Magazine. For a free design consultation and a relaxed and rewarding design and construction experience, contact us via e-mail, subboston@archadeck.net or by phone, 781-273-3500.

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