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Love your roof : Down with Icicles

Don’t let this balmy December weather fool you – winter is coming.  When the cold weather finally descends upon the city, signs of Jack Frost’s handiwork will begin to pop up everywhere.  For many of us, the quintessential image from inside the snow-globe is rows of sparkling icicles dangling from neighborhood eaves.

However picturesque, those glittering stalactites belie a problematic deficiency in your home and are much more sinister than they appear.  The problem is heat loss from insufficient insulation and/or venting in the attic, and it’s not just about your heating bill.  What’s happening is that the heat inside your house is able to transfer through your roof and melt the underside of the snow layer that’s accumulated on it.  When the snow-melt then flows down onto the eaves where there isn’t any heat, it refreezes, forming icicles and ice dams.

Icicles don’t do much damage to your home themselves, other than putting an extra load on your gutters and potentially loosening them from the roof structure behind.  But like smoke with fire, icicles almost always indicate ice damming – a much more problematic condition.  As winter drags on, the snow-melt trickles down the roof and freezes at the eave, then higher and higher up your roof as more water and ice builds up behind the growing “dam”.

Icicles with visible ice dams in and above the gutter. (photo credit:

A few things can happen as a result.  The water that flows under the snow and onto the ice dam will both freeze there on the surface and, worse, back up under the shingles.  When most new roofs are installed, a three-foot high strip of impermeable, rubber ice-and-water shield is laid down under the shingles along all the eaves, specifically to combat this phenomenon, but if an ice dam builds up above that height, any snow-melt will seep through the shingles and roofing paper and find its way into your house.  That water will crumble plaster ceilings, dampen and ruin insulation in the walls, bubble the paint, damage fine woodwork, and can cause rot in a wood structure and threaten electrical shorts and fires.  Needless to say, water inside your house is bad (not including the plumbing – showering and laundry are good for you!).

So, if you find icicles and ice dams on your house there are some things you can do and others you shouldn’t.  First, as long as you’re safe about it and wear a helmet, it doesn’t hurt to knock the icicles off with a hockey stick, but please resist the urge to wail away with a pick-axe to break off the ice buildup on your eaves.  This is how you get holes in your roof.  Pick-axe holes in your roof are bad (no qualifiers, this time!).

An extreme example of the damage that neglected roof damage can cause when water infiltrates the building envelope. (photo credit: flynn battaglia architects)

Roof heating wires or tape can be an alluring option, but if they’re not installed properly, or if you’re not diligent about turning them on when appropriate and turning them off when it’s just too cold for them to work, they can do more damage than good.  And even if all this is done right, the wires alone are not going to get rid of your ice dam and won’t melt the ice clogging up your gutters and downspouts enough to really remedy the problem.  Regularly shoveling or scraping the bottom three to six feet of snow from the roof is usually the best (and cheapest) option, if you can reach it.

If you want to be more proactive than reactive, installing new insulation or improving the ventilation in your attic can drastically reduce the amount of heat that can escape through the roof.  If you have insulation up in the rafters, baffles can and should be installed to create a small air space between the insulation and the underside of the roof deck and, in conjunction with vents at the eaves and at the roof ridge, allow a cold air current to pass through them and remove any warm air before it can heat up the snowpack on top of the roof.  Many homes older than a few decades don’t have eave and ridge vents incorporated into their roof constructions, but it’s usually a fairly simple job for a roofer or a capable handy homeowner and a friend.  There’s a little bit of carpentry and some climbing on the roof with a circular saw, but in most homes there’s enough room to retrofit these features.

In complicated cases, holes like these can be cut to allow cold air to flow through the roof structure, reducing heat transfer and protecting the integrity of the roofing material above.  (photo credit: flynn battaglia architects)

If you’re not the adventurous or DIY type, you can hire out the work and there are plenty of local contractors who can who can do it for you.  If you have unusual roof conditions, a local architect will be able to provide advice on the best way to tackle your retrofit.  For years, the U.S. Department of Energy has funded the Weatherization Assistance Program that has resources for qualifying households to assist in performing many of these energy efficiency-improving projects.  Links are below.

Stay toasty, my friends!

Flynn Battaglia Architects is an architectural firm focusing on design, historic preservation, and planning for higher education, housing and community projects.  It has an award-winning portfolio including national historic landmarks, colleges and universities, waterfronts and cultural resources.  Based in Buffalo, NY, the firm provides unique solutions delivering innovative, environmentally sensitive and cost conscious design.


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