Types of Roofs

There are many different options for your roof that you can choose from:

  • Cedar shakes and shingles: In the Pacific Northwest, old-growth cedar was hand split to create evenly patterned, vertical-grain shakes. Many of these roofs lasted 30 years or more, establishing cedar’s reputation as a fine-quality roofing product. Such roofs are still possible today but require extremely careful selection of material and high quality workmanship. One of the drawbacks of cedar, flammability, can be overcome with chemical treatment. Quality cedar can also be factory treated for wood rot. In order to get the maximum amount of use out of an untreated cedar shake roof, it is important to have the roof treated with a wood preservative (performed by a specialty contractor). Most cedar roofs can be cleaned and treated without pressure washing which can damage cedar roofing.
  • Composition roof: The newest of these roofs have fiberglass reinforcing mesh in the material and comes in a variety of colors, designs and qualities. It is not unusual to see a 25-year old composition roof in good condition, even though the original warranty was for 15 years. A properly installed composition roof requires very little maintenance other than a periodic visual inspection. The best way to inspect such a roof is with a good set of binoculars. Walking on a composition roof for the purpose of inspection should be kept to a minimum – good advice for all types of roofs. Composition roofs should be cleaned with a pressure washer.
  • Metal roof: Metal roofs are becoming very popular, not only because of their improved quality but also because they can provide a new spectrum of colors, clean lines and an alternative to traditional materials for low-pitched roofs. Does rain make more noise on metal roofs? Depends on who you ask and how the roof was installed. Typically the metal roofing is installed over solid sheeting of plywood or oriented strand board. This application reduces any noise problems from the roof while adding strength and longevity. The better quality metal roofs are called Standing Seam metal roofs and are designed in such a way as to hide all of the fasteners which attach the roof to the sheathing. This also gives the roof a very clean line and a very modern architectural look.
  • Tar and gravel roof: Also known as the built-up roof, it is used primarily on flat roofs up to a 3-in-12 pitch. Even flat roofs are sloped somewhat to prevent water from ponding. Tar and gravel roofs are constructed from alternating layers of heavy roofing felt and hot asphalt or tar and finished with a protective mineral coat, such as gravel or mica. The roofs are rated by how many layers are installed, usually from three to five. Read more about Built-up Roofing.
  • Modified bitumen roofing: This type of roofing combines many of the features in the standard tar and gravel roof with the addition of layers of polyester or fiberglass impregnated with bitumen, a derivative of tar or asphalt. The roofing is put down in multiple plies, or layers, and gains significant strength and resistance to weathering by adding the polyester membranes. Other bitumen modifier agents that enhance asphalt’s qualities include atactic polypropylene (APP) and styrene butadiene styrene (SBS). Read more about Bitumen Roofing.
  • EPDM rubber roofing: (EPDM) stands for ethylene propylene diene monomer and is a synthetic rubber membrane which can stretch up to 300% elongation, allowing for expansion and contraction in the building where it is installed. It is virtually unaffected by Ozone and UV radiation, therefore far longer lasting than bitumised products. It does not crack tear or split and is manufactured in various sizes of sheet greatly reducing the number of joints required in a large roof. Read more about Rubber Roofing.
  • Roll roofing: Commonly used for sheds or inexpensive roofs, it is low-cost roofing material with a short life. It is generically known as 90-pound felt because one roll, which covers 100 square feet, weighs 90 pounds. Although it is mineral-surfaced and made from the same material as asphalt shingles, it has a life expectancy of 10 years or less because it is only one layer deep. Shingles last longer because the manner in which they are overlapped makes them three layers deep.
  • Roofing felt: Technically, roofing felt is roll roofing, but it is never used by itself as a roofing material. Although water resistant, it is thin and tears easily. Made of asphalt-impregnated felt, it is used as an underlayment between the roof deck and the roofing material. It is sold as 15-pound or 30-pound felt, a figure that represents the weight of one square (100 square feet) of the material. It is sold in rolls 36 inches wide that cover either two or four squares. When using roofing felt, it is important to roll it out flat and smooth. Any wrinkles and bumps may show through after asphalt shingles are installed.
  • Slate roof: The slate roof is in a class by itself. As with yachts, if you have to ask the price…. But even here one needs to be careful. Not all slate will last in this climate. Vermont slate seems to be the best choice, and some imported Chinese slates are the worst. If you install a good slate roof, the best maintenance is to leave it alone for the first 75 years.