Heating Your Garage for Ice Dam Prevention: Doesn’t Work

Given how many ice dams you see across town, it might be a nice surprise to discover that garage roofs don’t develop ice dams nearly as often as do other kinds of roofs.

Why?  Because most of the time the garage isn’t heated.  That means it’s far less likely to cause the snow-melt that leads to ice dams.

On the off-chance you do see an ice dam on a typical garage, it’s all Mother Nature’s fault.  If it’s never or rarely heated on the inside, the melting snow on the roof is caused by the radiant heat from the sun, followed by freezing temperatures at night.  Doesn’t happen too often, fortunately.

But garage ice dams can easily happen if you heat your garage. 

That’s because most garages lack one thing that houses have: insulation.  In terms of preventing ice dams, even poor insulation is better than no insulation.  A heated garage can create a heated roof and ice dams even more quickly than your home can, because there’s no significant thermal barrier between the heat in your garage and the snow on your roof.

A leak in your garage typically isn’t as destructive as a leak in the rest of your home.  But water can cause damage any time it gets into a space that’s meant to be dry.

That’s especially true if you have a finished garage – one with insulation and sheetrock and maybe a pool table.  In that case, a leak can be every bit as destructive as in your living space.  Plus, your tools and car may fall prey to rust and falling sheetrock.

Are a toasty, snow-free car and a wintertime cigar cave worth risking an ice dam – one that may leak until you have to pay to get it removed?

If your answer is no, you’ll want to keep the heat off (or very low), or rake your roof, or both.  Maybe fork over for a remote-start for your car, so you can get those bun warmers going rather than heat the whole garage and risk ice dam pandemonium.