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by Jason Kempen, Home Performance Consultant
Contrary to popular belief, ice dams and icicles are not usually a roofing issue. Sure, roofers will add a
layer of rubber under your shingles to keep the “ice dam lake” from running back up under your shingles
and into your attic, but it doesn’t solve the problem. There is still a block of ice forming at the eaves of
your roof and large icicles are still pulling on your gutters and downspouts and worse is that ice dams
and icicles are a clear sign of energy loss. For all practical purposes, you are blowing heat (and money)
out of the top of your house into an already warming atmosphere.
Enter the practice of basic building science where the house is looked at as a system. Yes, warm air
generally wants to rise in a house. How is warm air working its way up into my attic? Where are the cold
drafts entering in the low areas of the house in this air exchange process?
When you start thinking about these two questions you are thinking like a building scientist and at the
heart of the ice damming and icicle solution.
Certainly attic insulation helps to keep your attic a cold buffering space between you and the outside,
but proper whole-home air sealing is where the science shows the biggest return on investment. For
this reason Focus on Energy offers higher rebates on air sealing at a higher rate than other
weatherization projects. They know that it will provide the most energy savings per dollar spent.
Focus on Energy Trade Allies know good air sealing work starts in your attic to seal the attic hatch and
seal top plates of the interior walls. Pushing your existing attic insulation aside exposes gaps and holes
to the attic for pipes, ducts, and wiring, all of which should properly air sealed. The chimney chase
should be sealed off with metal flashing and fire-caulk to create a fire block and seal it off from the
floors below. To complement this attic work, one must go into the basement and push fiberglass
insulation aside in the sill box cavities to look for utility penetrations for pipes, ducts or wiring that allow
cold air to flow into the house making downstairs floors feel cold.
All this, in addition to a thick blanket of insulation in your attic, keeps your attic cold and the living
spaces below warm. Instead of your snow melting and forming ice dams and icicles on those cold winter
days, you should have a blanket of snow resting peacefully on your roof.
May 26, 2021
As the Business Manager here at Accurate-Airtight Exteriors, I don't often get to observe the work being done by our crews out in the field and... Read more
November 20, 2019
Here at Accurate-Airtight Exteriors, we work with a multitude of different clients in the residential and commercial sector. We often have a... Read more
October 30, 2017
A home energy audit is one of the fundamental steps towards whipping your house into shape, reducing your energy consumption, and saving money on... Read more
September 13, 2017
Many residential buildings built in the 80s and 90s have an abundance of recessed can lights. As you can see in these photos they are often... Read more
January 6, 2017
Using a blower door--a device that sucks the air out of your house to simulate an especially windy day--is the best way to identify where your... Read more
October 19, 2016
The graph below shows which structural air-leaks drive up energy costs the most, allowing you to maximize efforts toward reinforcing your home's... Read more