Flat Roofing Materials. An article by Steven Briesemeister
It's a fact, some may suggest, that your roof is one of the most important parts of your house and is the one thing that provides the building structure, the building occupants and the building contents with protection from the elements! Evidence suggests that many roofs are in a state of disrepair but some homeowners ignore this until the roof gets worse or until the weather gets worse. With regular maintenance and the early identification and fixing of any problems you can usually avoid the big problems that have equally big price tags attached to them. Regular maintenance in this way will also help extend the life of your roof.
Selecting flat roofing materials.
Flat roofs have extra difficulties associated with them. Because they do not slope rainwater does not automatically run down the roof and drain off. It is absolutely vital that flat roofing materials are as water resistant and water tight as possible to prevent serious damage to the roof itself and to the rest of the building and it's contents. New types of flat roofing material are being used and while these offer more in the way of protection they are also more expensive as a general rule. There are still three main types of flat roofing materials that are used on a regular basis on new and older houses.
Built up flat roofing materials.
Built up roofing is basically just that. Built up roofing consists of laying down several layers of tar and water resistant materials and then covered with gravel. This is quite an old technique but the introduction of new waterproof materials has seen the strength and durability of this technique increase. The gravel acts as a good fire resistant layer and can be made to look very attractive. It is usually the cheapest of the flat roofing materials available, however, it is very heavy and may require strengthening of the joists. It is also impractical to use on residential houses that are being lived in because it smells terribly. The gravel itself can clog gutters and other vital aspects of water drainage.
Modified Bitumen flat roofing.
Modified bitumen is another stalwart in the world of flat roofing materials. Once upon a time it was necessary to use torchdown techniques that involved burning the roll of material onto the roof, however it is now possible to get adhesive varieties, thus cutting out the potential fire hazard that is sometimes associated. The mineral surface that is used to create modified bitumen can be created in light colors, effectively reflecting the heat and sun. This will cut down on your energy bills during the summer months, and it can even be installed by any avid (and competent) do it yourself fanatic.
Rubber membrane.
Rubber membrane is another method of coating your flat roof. As far as flat roofing materials go it is durable and resistant to general wear and tear. Leaks are easy to find and repair, but the cost is really quite high. The standard black rubber does not reflect heat and paying for a lighter membrane will cost you more, however, it is quick to fit and will cause little disruption to your house life during the process.
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Flat roofs
By Naldo camarones.
Flat roofs are a great way to keep a building safe from water. Knowing exactly what to do with a flat roof will ensure you have a working roof system that will last a long time.
Though they may look good, and are very common, flat roofs do require routine maintenance and detailed repair in order to effectively prevent water infiltration. If this is done correctly, you'll be happy with your flat roof for a very long time.
Flat roofs aren't as glamorous and/or popular as its newer counterparts, such as slate, tile, or copper roofs. However, they are just as important and require even more attention. In order to avoid throwing away money on short-term repairs, you should know exactly how flat roof systems are designed, the various types of flat roofs that are available, and the importance of routine inspection and maintenance.
A flat roof system works by providing a waterproof membrane over a building. It consists of one or more layers of hydrophobic materials that is placed over a structural deck with a vapor barrier that is typically placed between the deck and the roof membrane.
Flashing, or thin strips of material such as copper, intersect with the membrane and the other building components to prevent water infiltration. The water is then directed to drains, downspouts, and gutters by the roof's slight pitch.
There are four most common types of flat roof systems. Listed in order of increasing durability and cost, they are: roll asphalt, single-ply membrane, multiple-ply or built-up, and flat-seamed metal. They can range anywhere from as low as $2 per square foot for roll asphalt or single-ply roofing that is applied over and existing roof, to $20 per square foot or more for new metal roofs.
Used since the 1890s, asphalt roll roofing generally consists of one layer of asphalt-saturated organic or fiberglass base felts that are applied over roof felt with nails and cold asphalt cement and usually covered with a granular mineral surface. The seams are typically covered over with a roofing compound. It can last about 10 years.
Single-ply membrane roofing is the newest type of roofing material. It is often used to replace multiple-ply roofs. 10 to 12 year warranties are typical, but proper installation is crucial and maintenance is still required.
Multiple-ply or built-up roofing, also known as BUR, is made of overlapping rolls of saturated or coated felts or mats that are interspersed with layers of bitumen and surfaced with a granular roofing sheet, ballast, or tile pavers that are used to protect the underlying materials from the weather. BURs are designed to last 10 to 30 years, which depends on the materials used.
Ballast, or aggregate, of crushed stone or water-worn gravel is embedded in a coating of asphalt or coal tar. Since the ballast or tile pavers cover the membrane, it makes inspecting and maintaining the seams of the roof difficult.
Lastly, flat-seamed roofs have been used since the 19 th century. Made from small pieces of sheet metal soldered flush at the joints, it can last many decades depending on the quality of the material, maintenance, and exposure to the elements.
Galvanized metal does require regular painting in order to avoid corrosion and split seams need to be resoldered. Other metal surfaces, such as copper, can become pitted and pinholed from acid raid and usually requires replacing. Today copper, lead-coated copper, and terne-coated stainless steel are favored as long-lasting flat roofs.
