Older three-tab composition roofing was generally rated for 20 years of life, and in most cases met or exceeded that. Traditional three-tab is still available, but in addition to the flat profile of the older product styles, "dimensional" composition roofing products provide deeper shadow lines and longer life (25- to 50-year- or lifetime-rated thicknesses). In most cases these are ratings, not warranties.
Cost, color and style come in a variety of choices. Some manufacturers are installing moss-resistant granules that help eliminate moss for the first several years of the roof's life.
Most composition roofing materials can be laid over older roofing products (not over shakes), cutting strip-off and landfill costs. Please consult with your roofing supplier/contractor for specifics to your home for layered roofing, and keep in mind multiple roof layers will lessen the ultimate life in almost all cases.
Composition roofing is a proven product, although periodic defects arise in the manufacturing. The latest widespread problems occurred when manufacturers shifted from organic to fiberglass mats and altered asphalt content; internal cracking in individual shingles can be seen on numerous roofs installed from the late 1980s to the early 1990s, some requiring repair.
When switching from cedar to composition, a layer of plywood must be installed beneath (if not already in place) to allow the new composition roof to lay flat. While composition is generally less money, adding this layer of plywood makes the costs more comparable.
Cedar shakes
Cedar shakes were a superior roofing product years ago, cut and split from the heart of first-growth trees. These roofs, many lasting 75 years and more, did not require laying tar paper underneath.
Today, it is the lucky homeowner who can milk 20 years from a typical cedar roof.
As first-growth timber was logged off and environmental pressures increased, the material became thinner, smaller and of lesser quality. Tar paper became de rigueur as the newer shakes began to eventually split, cup and leak. But tar paper lessened the ability of the wood to breathe and dry from below; some say this, too, led to quicker deterioration.
Within the past few years, it has become unheard of to find the required slats beneath new-construction wood roofs. The solid plywood or oriented strand board (a less-expensive plywood substitute known as OSB) further decreases breathability of a wood roof.
Shakes are also high maintenance and can ignite more easily than other materials. If that sounds like bad news, consider the qualities shakes possess beyond all others: undisputed good looks and complete environmental renewability (albeit in quite a few years). Shakes are excellent in high winds and hold up well in hail compared with other materials.
Recent improvements include fire treating and wood preserving at the time of milling as extra-cost options, this obviously adding to their attractiveness.
You can buy cedar in multiple "cuts" and grades, depending on budget and style desired. Shakes are split, and shingles are cut. Shingles are thinner and more uniform, this characteristic being very important for historic buildings. Cedar shingles are rarely used because of cost.
Metal
Metal roofing is absolutely second to none in snowy areas because it is so slippery, allowing snow to slide off easily. This characteristic also makes it impossible to walk on when wet. Depending on the budget, metal roofing comes with visible seams and fasteners, or hidden.
Rumor has it that every raindrop is heard under a metal roof. This may be true in a barn, but not necessarily so in a house. You'll hear raindrops no more than you would with any other roof type under a properly insulated roof system.
The stylization of metal is unique and hasn't caught on heavily in urban areas, although having vertical seams is very attractive, if not more attractive, than horizontal seams or individual shingles, even in urban settings, in my humble opinion.
Lifespan of metal roofing is variable from 50 years and up, depending on gauge of the material used.
Metal shingles/stone-coated steel roofing is something many people overlook when considering roofing types. Most are designed to be laid over existing roofing materials and provide a "permanent" roof coating. The granulization baked onto the metal makes these roofs able to be walked on. Metal roofing of any kind generally requires workers who specialize in this material for installation.
Next week: tile roofs, slate, imitation shake and pricing. |
