Choosing the Right Roofing Material
Choosing the right roofing material can be a bit of an overwhelming task, particularly if your budget doesn’t limit the possibilities. There are a vast array of roofing materials that a home owner has to choose from. Each has its pros and cons. Since asphalt shingles are the dominant product on the market today, this website will tend to focus on them regarding installation.
Without going into too much detail, here are a few products worth considering:
- Concrete roof tiles have been around for a while now and have proven to be an extremely resilient product. They are expensive, but the concrete tile roofs that we installed in the late 70’s are as good today as the day we put them on. They are very heavy and require a constructed framework of horizontal strapping to lay on. Also, you would have to ensure your roof structure is engineered to be able to withstand the extra weight. They come in a variety of colors and designs.
- Metal roofing also comes in a variety of configurations and colors. Usually somewhat more expensive than asphalt shingles because it also requires the construction of a horizontal framework made of 2”x6” (at minimum) strapping for the panels to rest on. A very good product, but a word of caution about installation. From my experience, I have seen many roofs where metal roofing has been laid on top of old asphalt shingles without strapping the roof first. Do not do this! Metal roofing screws need to be screwed snug into solid wood, not plywood. Old curled up shingles create bumps and elevations under the metal that cause your screws to be somewhat elevated from the roof surface. To make them snug, you would have to ‘dimple’ the metal. Dimpled metal and elevated screws will both cause issues that will limit the life-span of your roof. Dimpled metal will rust sooner and elevated screws will loosen over time by vibrations (washing machines, high winds etc). Snow and ice repeatedly sliding off your roof will also force elevated screws to loose over time.
- Synthetic roofing shingles are a wonderful alternative and my personal preference because many are made from recycled plastics and rubber. They are often designed with a thicker profile in an effort to look like cedar shakes and shingles. The cost is less than cedar but substantially more than asphalt shingles. They also come in a variety of styles and usually have really good warranties to back them up. They have been around now for a couple decades and appear to be holding up nicely. Test results show them to last longer than cedar and metal products. The one drawback is that they do cause snow and ice to slide off them, much like metal. There are a variety of snow slide products out there to inhibit slides but I won’t go into that in this post.
- Cedar roofing products are beautiful to look at when installed initially. Many other products try to mimic the thick profile appearance of cedar. Cedar is very expensive. The trick to longevity with cedar, besides proper installation, is getting high quality edge grain material. Insist on 100% edge grain shakes from your supplier. With an edge grain cedar shake, the grain is vertical to the butt end and the annual rings from the trees growth are many and tightly spaced. The alternative is a flat grain, where the grain is horizontal to the butt end and the annual rings are widely spaced and sometimes barely visible. It doesn’t take long for a flat grain shake to dry out and split into a mass of cedar slivers. The only thing holding out the elements is the thing felt paper under each row. You also need to be aware of the fire hazard of cedar shakes. Cedar products have been slowly losing popularity because of this one issue with them. They can be fire treated, but this adds extra cost to an already fairly expensive product. You also need to remember that cedar shake are typically applied onto wood strapping rather than plywood sheathing. This means there are 6-8″ gaps between the straps that are not conducive for installing asphalt or synthetic shingles. To replace a cedar shake roof with asphalt or synthetic shingles you would need to install plywood sheathing over top of the strapping before shingling.
- Asphalt shingles are by far the least expensive of all sloped roofing materials and therefore the most popular. They are also the simplest to install and can fairly easily be done by a reasonably fit and capable home owner. I’ve talked about the two major types of asphalt shingles in previous posts, describing their individual applications, pros and cons. For these reasons, this website is primarily concerned with the application of asphalt shingles.
All these products are designed to be used on slopes of 4:12 (slopes with 4” rise for every 12” of horizontal) and greater. Slopes less than that are technically considered flat and require a whole other assortment of materials and roofing methods that are beyond the scope of this website. Having said that, there are exceptions where you can install them on a lower pitch but it requires some extra measures that need to be taken. I will try to explain those at the appropriate time.
My next post will give some tips on one of the toughest aspects of roofing your house … loading material onto the roof and stripping off the old roof.