Imagine, you are standing on the sidewalk, looking at an average house. You see the siding, the windows, the front door, and high up, you see the roof. Does the roof have asphalt shingles? Wood shakes maybe? Maybe it is made of metal or rubber tiles? What you see is where the focus goes, but it’s what you don’t see that really matters. There’s more to the roof than meets the eye. So let’s talk about what goes on under the shingles.

roof deck

We learn to crawl before we walk, so when we talk about roofs, let’s start with ground zero, the surface area of ​​your roof that is made of wood. Its wooden roof deck is comparable to the metal body of a car. It is installed over the basic frame of the house to provide a surface area on which to install the shingles. Without a roof deck installed on your home, there would be nowhere to install your shingles. And of course, without the shingles, the roof deck would rot from exposure to sun, rain, snow and ice, etc. It would not be a comfortable home at all!

In newer homes, sheets of plywood or OSB boards are fastened on top of the attic wood joists to form the roof deck. Plywood or OSB boards are installed in a staggered fashion with small gaps between them to allow the wood to expand and contract as it warms in the summer and cools in the winter. Older homes often have 2″ x 6″ lengths installed instead of plywood or OSB board. When it’s time to replace your roof system, remember to have your Calgary roofing contractor replace all damaged wood.

Remember, if your roof deck is rotting or damaged in any way, people walking on your roof could crack or break the wood, causing further damage to the roofing system, such as the shingles…and to the person walking on it. path. in that! However, most roof coverings can withstand some exposure to water or ice before they need to be replaced.

Metal: drip edge and sloped edge

The drip edge and raked edge is the first part of the roof system to be installed. It is a long, narrow piece of metal that is installed along each end of the roof deck, that is, along the eave gutter and along the gable ends.

Some local area building codes require the installation of Drip Edge and Rake Edge and other building codes do not. Check with your local city building offices to find out. In Alberta, for example, the Building Code does not require the installation of drip edge or rake edge. Therefore, many new homes and/or budget roof systems do not have drip edge installed to allow for more affordable roof prices. However, we recommend that drip edge and raked edge be installed on every roof system, no exceptions.

Drip and rake edge is available in a variety of different colors and sizes and can be custom built for your roof system needs. Installing a proper drip edge often saves hundreds and sometimes even thousands of dollars when your roof system needs to be replaced.

If your roof system does not currently have a sloped or drip edge installed, don’t panic, it will survive quite well. Just keep in mind that when your roof needs to be replaced, the roofing contractor may need to replace part of your wooden roof deck as needed.

Metal: Chimneys and Skylights

Arguably the most important part of any complete roof system. Metal installed in valleys, chimneys and skylights bears the brunt of water flow on each roof. Improperly installed, a new ceiling system can turn your living room into a waterfall.

Every chimney and skylight needs what’s known as a “back tray,” which consists of sheets of metal bent at about a 90 degree angle (depending on the slope of your roof) and tucked under the shingles and under the siding, stucco or flashing on chimney or skylight. Each back pan needs a small 2″ section of metal that protrudes 1″ or more from either side of the chimney or skylight to divert water away from the corners. The water should hit the metal back pan and go to either side where it can continue its way into the eave channel.

Metal: Valleys

Just as water runs along the valleys between two mountains, water runs along the valleys at the peaks of their roofs. Valleys generally receive the highest concentration of water flowing through them, so installing them correctly is extremely important!

As mentioned in the Leak Barrier section, valleys have Leak Barriers installed below them. Although some building codes do not require the installation of such a seepage barrier, we recommend that one always be installed in every valley.

A word of caution: Many roofing contractors install valleys in a style called “closed.” A closed valley consists of shingles woven into the valley, as opposed to an ‘open’ valley which has metal sheets running from top to bottom. Both the ‘open’ and ‘closed’ styles of installation are acceptable by most building codes and most manufacturers, however the ‘open’ style installation has consistently outperformed the ‘closed’ style. .. and it costs exactly the same price to install. Ask your roofing contractor to use the ‘open’ installation style for the valleys of your roofs, this could save you from having to replace your roof system prematurely and may also prevent headaches in the long run. Typically, an ‘open’ valley is installed with 4′ wide, 30 gauge sheet metal, which comes in 10′ sheets. This metal can be ordered in any color to match the shingles in your roof system.

leak barrier

Think of a leak barrier as a “second layer” of protection for your roof deck. A backup plan, if you will, and also a protection against moisture buildup. Leak Barriers are almost always installed over drip edge and metal rake trim along eave areas, gable areas, and valleys due to the risk these areas present for seepage, ice dams , deterioration of the tiles and reflux of water.

If you’ve ever looked at your roof in the winter, you’ll notice how ice and snow accumulate along the eave gutters and into the valleys of the roof. As with rake edge and drip edge, some building codes require the installation of leak barriers and some building codes do not. In Alberta, the Building Code requires that a leak barrier be installed in all eave channels and valley areas of a roof system due to issues related to snow and ice buildup. As an optional upgrade, some higher-end roof systems even have leak barriers installed on top of the entire roof deck (as opposed to just along the special areas just mentioned) where a leak barrier would normally have been installed. standard roof deck protection.

Virtually every roof in Calgary, Alberta has leak barriers installed, and many different types of leak barriers are available on the market today, each offering a different level of reliability, functionality, and warranty and produced by many manufacturers. different manufacturers.

Choosing the right leak barrier and installing it correctly is an important step in every roof system. Talk to your roofing contractor to learn more about leak barriers, how to choose the right one, and how to choose a professional roofing contractor to install it.

roof deck protection

Roof deck protection is very similar to a leak barrier. The difference is that the roof deck protection is installed over the entire roof deck area instead of just in “special areas” as we discussed in the Leak Barrier section.

Roof deck protection is generally inferior in quality to a leak barrier. However, as with leak barriers, there are many different types of roof deck protection available to choose from, from basic felt/tar paper to advanced plastic woven sheets of tear and wrinkle proof material. Choosing reliable roof deck protection is an important part of a quality roof system.

A word of caution; most roofing companies use felt paper as roof decking protection. Although the use of felt paper is standard and acceptable practice, some problems can arise if the felt paper becomes wet during or after installation. Have you ever noticed how paper tends to curl when it dries after it was wet? Similarly, felt paper can curl if touched by water or excess moisture. For this reason, and because the cost is quite low, we recommend installing higher quality base deck protection, such as GAF/ELK base deck armor. For a relatively small additional cost, you’ll be rewarded with much more reliable roof deck protection.

Ask your trusted local roofing contractor which underlayment would be best for your roofing system and why.

Conclusion

So there it is, life under the shingles. See how much happens behind the scenes? Professional roofing contractors know this inside and out and can help immensely in ensuring that a roofing system is reliable for many years. Product suppliers like GAF/Elk and IKO can also help answer specific product questions.

All the best with your roofing project, and remember, be proactive, make informed decisions.