Mike Holmes: Snow piling up on your house is a good indicator of the roof’s condition

Mike Holmes, Postmedia News | February 7, 2015 – Postmedia News 

The icicles on this home as well as the bare roof ridge show that there's some problem with the insulation of this home.

The Holmes GroupThe icicles on this home as well as the bare roof ridge show that there’s some problem with the insulation of this home.

Many cities across the country were hit with a major winter storm earlier this week, and for some, it was the first big one of the season.

One area of the house that gets hit the hardest during a winter storm is the roof. It should be strong enough to take the brunt of bad weather, and you need to make sure it can.

To start, take a look at your roof. Ideally, it shouldn’t get a lot of snow buildup; the snow should just slick right off. Flat roofs get the most snow buildup, and that’s one reason they typically get more leaks.

Ice also tends to accumulate on lower-sloped roofs because these roofs are difficult to insulate and ventilate — there often isn’t much room for insulation and air movement in a shallow attic.

If your roof gets a decent amount of snow on it, make sure it’s not melting in specific spots. That means there’s heat loss likely due to poor insulation and/or ventilation in the attic.

After a snowfall, every homeowner should take a look at their roof and check for hot spots — areas on the roof where the snow has melted. It’s normal for some melting around venting and fireplace exhausts, but you shouldn’t see any bare patches on your roof. A snow-covered roof means your attic is doing its job.

Also keep an eye out for icicles — another sign of heat loss. If your roof is warm enough to melt the snow but it’s cold enough outside for snow to refreeze, your roof is losing heat. That’s not healthy for your energy bills or the environment.

Cathedral ceilings or hot roofs can be prone to heat loss, ice dams, condensation and moisture issues. Some municipalities don’t allow them.

A cathedral roof is one with no attic space, so the underside of the roof should be insulated with spray foam. There needs to be enough space in the roof framing for the right thickness of spray foam to be applied, which provides the necessary R-value. That can be tricky to accomplish.

What about the weight of snow itself? If there’s ice too, that can be a heavy load. Add the weight of two layers of shingles and that’s one roof I wouldn’t want over my head.

I always recommend removing the first layer of shingles when re-shingling. It’s not against code to have two layers of shingles in most regions, but you shouldn’t put more weight and stress on your roof than is necessary. It can wear it out prematurely and void the warranty on the new shingles.

I also like to see ice and water shield installed over the entire roof, on top of the plywood sheathing (yes, it should be plywood) — not just along the edges near gutters. This adds a second layer of protection against leaks and moisture, so if water gets in below the shingles the sheathing is watertight.

Another reason I like ice and water shield is it seals around nails, unlike tar paper, roofing felt or asphalt paper. If you have shingles on your roof, as most North American homes do, for every nail that goes through the tar paper there’s a tiny hole — an open invitation for water in your attic.

Check your attic (and garage) after a storm too. If you see frost on the sheathing it’s not a good sign. It means your attic isn’t breathing, which could lead to mould or rot. Any signs of mould, rot or bad structure in your roof is a red flag. Call a professional roofer.

Snow shouldn’t be coming in either, as it too can lead to mould and rot. Plus, big enough openings in your roof structure leaves room for critters to get in.

Your roof and attic are crucial when it comes to protecting your home over winter. Keep them in top shape.

Watch Mike Holmes on Holmes Makes It Right on HGTV. For more information visit makeitright.ca.

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