We all strive to keep the proverbial "roof over our heads" and once you have it you do need to pay attention to it. The job of a roof is simple---keep out water. The forces that work against it are many--the sun and ultraviolet rays, heat, inadequate insulation, and improperly applied materials are just a few. Most people want a roof that's not too expensive, requires no maintenance and lasts forever but in making choices it is very important to remember that cost alone does not determine quality. There are many kinds of roofing and there are some issues specific to each kind so we hope you'll take the time to go through the list. Not all of these materials will meet the needs of your home but by carefully selecting the right material, making sure it's properly installed and performing some maintenance occasionally, you can have a roof that functions properly for 20-50 years or even longer. If you have any additional questions please just give us a call.
Metal roofs are coming back into vogue. In the late 1700's zinc, copper and lead were the most popular materials used for roofing. Nationally, standing-seam steel roofing is the most popular residential metal roofing today. (The term standing-seam describes the upturned edge of one metal panel that connects it to adjacent sections, creating distinctive vertical lines and a trendy historical look.) Metal can also be made to resemble wood shakes, clay tiles, shingles, and Victorian metal tiles. Aluminum or coated steel is formed into individual shingles or tiles or into modular panels four feet long that mimic a row of shingles or tiles.
Metal roofs are durable, fire retardant and almost maintenance free. They are also energy efficient- metal reflects heat and blocks its transfer into the attic. Research by the Florida Solar Energy Center in 1985 showed that metal absorbes 34 % less heat than asphalt shingles and homeowners switching to metal roofing reported savings up to 20% on their energy bills.
Steel roofs offer other environmental benefits as well. They are made from 60-65% recyclable material and because it weighs very little, metal roofing can be installed over existing roofs eliminating the need to dispose of excess material in a landfill.
Installing some metal roofing can be an involved process and should be done by a professional. The inital cost of a premium metal roof is higher than most other roofing materials. You will need to compute the lifecycle cost to see if paying more to begin with for a metal roof will prove to be a better investment than some other form of roofing.
Asphalt shingles are the perfect choice for a clean look at an affordable price. Higher quality versions offer a more durable option and may be available with recycled content. Most brands offer Class A fire protection. Asphalt shingle roofs normally last 15-30 years for standard grade shingles, and up to 40 year warranties are provided for top end architectural shingles. Maximizing life also depends on the quality of the workmanship and maintenance. When the roof has lived its life, another layer can be added to restore the roof. A second layer roof generally provides between ½ and 2/3 the life of a one layer roof (due largely to greater heat retention), and at the end of its life, the roof must be stripped of all shingles before re-roofing. You will find that it is generally more cost effective to strip the first layer before replacing it. Triple layers are typically not permitted because of the extreme weight load they place on the structure. On the negative side, asphalt shingles don't have the life span of other materials like tile or metal and they don't offer the dimensional look of tile or wood shakes. They can blow off in a high wind.
Shingles can only repel water if properly installed and in good condition. Any irregularities such as torn or damaged tabs, abrasion or erosion of the mineral surface, raised fasteners (often appearing as if something is stuck under the shingle), or other flaws can allow water to pass through or around the shingle and into the house. Proper and prompt repairs can lengthen roof life significantly. Patches, sealant or caulks can be signs that some leaks have already occurred. The lighter the shingles in color, the less heat they will absorb from the sun. This usually translates into less thermal stress and a longer life for the roof. Use the lightest colors you are comfortable using.
Wood shakes offer a natural look with a lot of character. They offer some energy benfits too helping to insulate the attic and allowing the house to breathe by circulating air through the small openings under the felt rows on which wooden shingles are laid. A wood shake roof does demand proper maintenance and repair though or it will not last as long as other products. In the high heat and humidity of the
Wood roofs can last 15 to 30 years, depending to a great extent on how they are installed and maintained. The quality of shingle or shake, the slope of the roof (steeper is better), the amount of exposed shingle, and the amount of sun or shade can greatly affect roof life. Open sheathing (boards with spaces between them) which are nailed to the rafters or trusses and are then covered with 30 pound roofing felt under the shingles or shakes can give the longest life thanks to good ventilation on the underside and edges of the shingles which promotes even drying. If mounted on solid sheathing such as plywood or waferboard, butted too closely together, or otherwise prevented from drying evenly on all surfaces, curling, warping and splitting can be accelerated. Cracked, curled, or displaced shingles or shakes should be repaired. As a rule of thumb, replacement of the entire roof covering may be logical if more than ten percent of the wood roof requires repair. Consider professional cleaning annually with high-pressure air or water to help prolong life and reduce moss and fungus development. Every five years or so treatment with special chemicals can improve life expectancy. Walking on a wood roof does damage and should be discouraged!
Roofing tile is a good choice for homes with a southwestern, Italian or Spanish Mission design. This is a material that will last for a very long time and frequently it's life span is longer than the material underneath it. Tiles won't rot or burn and they can't be harmed by insects. It requires little maintenance and comes in a variety of colors, types, styles and brands.
The biggest drawback to tile is its weight. Depending on the material used to make it, tile can be very heavy--so heavy that extra roof support can be required. Originally made from clay, new tiles are being made from lighter materials. Lightweight metal tiles can be installed over existing roofs although we would not recommend that be done. With some new materials, color is added only on the surface of the tile and they can fade over time.
Some types of tiles are fragile, so walking on them can break them making it more difficult to accomplish maintenance like painting or cleaning rain gutters or fireplaces. Initial installation can be complicated.
Finally, tile can cost more than other roofing materials, so again, you must evaluate the cost over the life span of the material and decided whether it is worthwhile for you.
Slate is actual shingle-like slivers of rock and typically shows up on the most expensive homes. It is an expensive choice but it does offer a natural look and can be laid out in a variety of patterns. It's benefits are identical to tile: a very long lifespan, good fire protection, low maintenance and an invulnerability to rot and insects. It comes in a good selection of sizes and colors although colors are limited to those found in nature.
Like tile, slate can be very heavy, sometimes requiring expensive extra support. It, too, is breakable enough that walking on it is difficult complicating such tasks as rooftop maintenance, gutter cleaning and painting.
Yes, concrete is now a roofing material. Shingles, simulated wood shakes, lighter-weight tiles and concrete panels are being manufactured from a variety of fiber-reinforced cement products. Some are coated with plastics, enamels, or thin metals and some contain recycled material. Althought the products themselves are not recyclable, they are a good choice for durability and resource efficiency.
The advantages to concrete roofing vary but in general it has a long life span, requires little maintenance, offers good fire protection and is resistant to rot and insects. Concrete mixed with cellulose can mimic the appearance of wood shakes at the same time improving the durability and fire protection that real wood gives. It can approximate the look of clay tile or slate while eliminating the structural problems caused by the weight of the real material.
Concrete is more expensive than some roofing materials and early types of concrete roofing had trouble with the material curling, breaking and changing color. Technology has improved though and most of these problems have been eliminated. Style and color choices are expanding and by mixing the cement with additives, manufacturers are able to make lighter and lighter products.
HOT MOPPED ASPHALT
This is used primarily on flat or semi-flat roofs that have good access and proper drainage. The advantage to it is that is is less expensive than other roofing materials and holds up fairly well when properly applied. The technique does result in a roof that's not very pretty although it is generally covered with a layer of decorative stone to improve the appearance.
You've probably noticed roofing projects that use this material since it requires a large kettle of melted asphalt. When being applied it produces a huge amount of off-gassing that not only stinks but also poses a health risk to the installers. Because its fumes contribute to smog there are urban areas that restrict its use.
Any time the plane of the roof is broken, flashing is used to avoid leaks where dissimilar items meet. Flashing can be metal such as aluminum or copper, or can be made of plastics such as neoprene. These can deteriorate over time and can allow leaks that may be detectable in the attic or at ceilings. Review them as part of your routine maintenance, and consider having all flashing replaced when reroofing. Even if the flashing outlasts the first roof, it will probably not outlast a second, and may contribute to problems with the new roof.
Watch for signs of deterioration in the brick and mortar, especially above the roofline. Spalling brick (surface deterioration of the masonry) is quite common at the top of the chimney, and this frequently is accelerated by cracks in the chimney crown (the concrete cap pad on top of the chimney). If these are well-caulked and sealed, moisture penetration resulting in freeze damage may be reduced, and repairs postponed if not avoided completely. Severe spalling can ultimately make rebuilding the top of the chimney necessary.
Prior to the early 1980’s, all dwellings that shared a common wall (townhouses, duplexes, and so on) were required to have masonry party walls extending several feet above the roof to provide an adequate firebreak. In order to eliminate these unsightly parapet walls without compromising safety, builders and architects began using new Fire Retardant Treated plywood within 4’ of the common wall as a substitute for these parapets. Unfortunately, early generations of this material did not hold up well, and the combination of the heat buildup common in attics coupled with chemical reactions within the wood frequently led to failures such as delaminating and cellular breakdown in the plywood, corrosion of roof nails and truss plates, and complete loss of structural integrity in many roofs. High quality attic ventilation (to reduce heat buildup) coupled with reformulated treatment chemicals has greatly reduced this problem in recent years. Property at greatest risk was generally built between 1979 and 1985.
Most attics are insulated to some degree with a variety of materials and methods. Generally, unless already insulated to R-30 (equivalent to approximately 10-12” of fiberglass), consider adding more. Many attics have a paper vapor or moisture barrier installed against the attic floor (the top of the ceiling below) to help hold out rising moisture from the inhabited areas. If there is a vapor barrier, insulation being added should not have one – condensation can develop between the two barriers. If there are already two in place, the top one should be cut or sliced every couple of feet to help prevent condensation from developing. Avoid allowing insulation to pack in the eaves to help reduce ice damming, which can cause roof leaks from snow runoff that becomes trapped
Significant portions of this roofing discussion are from the Consumer Energy Center at http://www.consumerenergycenter.org. Please visit their site for more information on a variety of issues.