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Archive for January, 2018|Monthly archive page

Ice Dams

In Winter Tips For Your Home on January 9, 2018 at 10:05 am

Remember these two words “Ice Dams”.

In the coming months there’s a good chance you’ll be cursing them because of the damage they could cause.

The melting of the snow on your roof causes ice dams. As the snow melts, it gets to the cold overhangs, eaves and gutters. The snow freezes and starts accumulating a large ice block or “dam”.

As more snow melts, the cold ice water runs down the roof toward the dam. The water refreezes as the sun goes down and that ice starts backing up. As you might imagine, shingles are not waterproof. They are designed to shed water so the accumulating ice is now backing up beneath the shingles.

As the ice melts, it rots the roof structure, ruins ceilings, walls and furnishings and causes mold to flourish.

Your best defense against ice dams is increasing the amount of insulation and ventilation in your attic as well as installing ice shields.

The heat that is melting the snow is heat you’ve paid for. It is lost through your attic because you do not have enough insulation.

There are a few things you can do to reduce ice dams and eliminate any damage they can cause to your house. You should bring the level of insulation up to R-49 or higher. Doing so will save you money on heating and cooling costs and it will make your house more comfortable in the summer as well as the winter. The added insulation reduces or stops the heat from escaping into the attic and keeps it where you want it, in the living space of the house. Go to www.technihouseinspections.com and click on “Insulation- Packing it In” to find out how much insulation you need and how to do it yourself or hire-it-done.

Adding adequate ventilation to your attic cools the attic area above the insulation, which also helps to reduce ice dams, prolong the life of your shingles and also saves on cooling costs. But Michigan has severe winters and ice dams are inevitable. The only way to eliminate damage from backing up of the ice is to install “ice shields” under your shingles.

When re-roofing, you should remove the shingles and install ice dam membranes. In our area, code requires at least “two layers of underlayment cemented together or a self-adhering polymer modified bitumen sheet shall be used in lieu of normal underlayment and extend from the lowest edges of all roof surfaces to a point at least 24-inches (610mm) inside the exterior wall line of a building.”

The only exceptions are detached structures such as sheds or garages that do not have a heating and/or cooling system.

That code is from the 2006 Michigan Residential Code but remember that is the minimum code. In reality, you should go 6 to 9-feet depending on the slope of your roof. Lower slope roofs should have more ice dam membranes. You should also install the membranes in and all the way up all valleys and around all skylights.

By the way, if you don’t think heat you’re paying for is causing the ice dams, go through old photos. Better yet, try and remember what the roof looked like a couple days after a snowfall. You’ll see snow on the garage and porch roofs. You’ll see snow along the overhangs of the house, but the snow over living spaces is gone or melting. If the sun alone were causing the snow to melt, it would be melting evenly all over the roof.

Many people use de-icing cables on their roofs to reduce and melt the ice accumulation. Oftentimes it is successful. But remember, heat loss, along with freezing weather are causing the ice dams. I have on occasion seen where those electric de-icing cables caused secondary ice dams farther up the roof. While many people swear by them, I do not feel they are all that effective.

They can be expensive to operate if left on for long periods of time. Every inch of them needs to be inspected annually to verify they have not become brittle or cracked.

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