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How a Roof Works

It’s something we all have but really, how much thought do you really put into your roof? Sure, if there is a problem with it it is thought about, but on an ordinary day, do you know what your roof is made of and how it has been affixed to the top of your house?

When your house was built, it was framed into the shape that you see today. On to the framing, or rafters at the top goes sheets of plywood which is then referred to as the roof deck. This will be the area that the roofing material will be attached to, but before the shingles come out, there are some other steps to get through.

We all know that water is the mortal enemy of the roof. Roofs are designed to keep water in the form or rain, sleet, hail and snow away from your home and also designed to withstand wind that can pick up the shingles and render them useless. To help with that, a roof is designed in layers. The layer that goes onto the roof deck is a piece of #15 felt, a thick material that intercepts water that may get past a damaged shingle. This material can also be reinforced with fiberglass for added strength and moisture wicking capability. Next goes the drip edge, strips of aluminum or galvanized steel that helps block the wind and rain from the edge of the roof surface in addition to helping to maintain a tight seal.

Now it’s time for the shingles. Shingles can come in all colours, sizes and shapes and can be made of slate, wood, metal and even recycled tires. By far the most popular shingles are made of asphalt. These shingles have been used for over a hundred years and are beloved by many because they are easy to install, easy to repair, have a great warranty and are by far the cheapest option available. These shingles start with a felt or fibreglass mat that is then impregnated with asphalt. Granules are then added to the outer layer that helps to prevent UV light damage as well as giving them their unique look. These shingles are placed on the roof deck over top of the felt layer and nailed to each other and the roof deck. A factory applied adhesive that is heat sensitive then allows the shingles to be further attached to the roof and they become self-sealing with a summer worth of hot sun beaming down on them.

A roof is only as good as the sum of its parts. Everything overlaps to work together to resist the weather, shedding water and resisting wind. If a piece of the roof is compromised, it could mean weather gets into the house, and that’s something no one wants to see.