How many homes are topped by asphalt shingles? Why?
Asphalt shingles are the leading choice for residential roofing in the United States because they provide quality, durability, versatility and economy. Over 12.5 billion square feet of asphalt shingle products are manufactured annually – enough to cover more than 5 million homes every year. Four out of five homes are roofed with asphalt shingles.
Asphalt shingles offer consumers the broadest array of colors, shapes, and textures available. With an enormous range of styles, asphalt shingles can match almost every type of architectural design and achieve virtually any desired effect – and do it affordably.
Product Performance – Asphalt shingles perform well in extreme temperatures and in areas where wind, water and ice are prevalent.
Affordability – The efficient, high-volume production and relatively low application cost of asphalt shingles provide consumers with an overall value that is tough for other roofing materials to match, especially in terms of comparable life expectancy.
Low Maintenance – Asphalt shingles, when properly chosen and applied, require little or no regular up keep, and are easily repaired if damaged.
Ease of Application – Asphalt shingles are considered to be the easiest of all standard roofing materials to apply. In addition, the flexibility and strength of asphalt shingles supports their application on a wide variety of roof designs.
Fire and Wind Resistance – Asphalt shingles are manufactured to resist external fire and flammability standards, and carry Class A, B or C fire ratings, with Class A providing the greatest fire resistance. These fire ratings are defined by nationally recognized standards and tested by independent testing agencies. In addition, many asphalt shingles carrying a “wind resistance” label indicating that they have been manufactured and tested to demonstrate acceptable resistance in high-wind locations.
What are the different types of asphalt shingles?
Strip Shingles – These asphalt shingles are approximately three times as long as they are wide. Manufactured in both standard and metric dimensions, strip shingles are distinguished by the number of cutouts or tabs that they have. The most common type of shingle is the “three-tab” shingle. Different textural and lighting/shadowing effects can be achieved with strip shingles depending on the number, shape and alignment of the cutouts.
Laminated Shingles – These special shingles contain more than one layer of tabs to create extra thickness. They are also referred to as three-dimensional or architectural shingles because they create visual depth on a roof and impart a custom look. Laminated shingles continue to be a favorite among builders, roofing contractors, and home buyers.
Interlocking Shingles – As the name suggests interlocking asphalt shingles are individual shingles that mechanically fasten to each other and are used to provide greater wind resistance. They come in various shapes and sizes providing a wide range of design possibilities.
Large Format Shingles – Generally rectangular or hexagonal in shape, these shingles do not utilize cutouts or tabs.
How do I determine if a roof should be replaced?
Sooner or later every roof needs to be replaced, usually due to the long-term effects of weathering. If a residential roof is more than 20 years old, it is a prime candidate for re-roofing. To determine if you need a new roof do these two things:
On the Ground, walk around your home and inspect your roof with binoculars. Look for cracked, curled or missing shingles as well as any excessive loss of the protective mineral granules.
DO NOT CLIMB ON THE ROOF; walking on the roof is dangerous and can damage your roof.
In your attic, take a flashlight and look at the underside of the roof deck and rafters for any stains or wet spots indicating water leaks.
Can the new shingles be applied over my existing roof?
Sometimes – Asphalt shingles can often be applied directly over existing roofs without the necessity of tearing off the old roof. However, new shingles cannot be properly applied over hard or brittle materials, uneven surfaces for nailing, or roof decks with warped, rotted or unsound support. In these circumstances, the material should first be replaced or repaired.
Some local ordinances forbid re-roofing over two or more layers of shingles. If a home already has been shingled several times, it is important to first determine if the roof deck can support another layer of shingles before undertaking any re-roofing project. Powell Roofing seldom puts a new roof over an old roof, we tear off down to the decking to be able to do a proper inspection of the surface.
What is Roll Roofing?
In addition to asphalt shingles, asphalt roll products are used for residential roofing applications (primarily for underlayments and flashings). There are four basic types of roll roofing materials, each tailored for use in certain job requirements:
Smooth Surfaced Roll Roofing – Also termed coated felt, this smooth-surfaced roll roofing is covered with ground talc or mica. It is used primarily as flashing to seal the roof at intersections and protrusions, and for providing extra deck protections at the roof’s eaves and valleys.
Saturated Felt – This asphalt-impregnated, organic-based felt is used as an underlayment between the roof deck and the roofing materials. Saturated felt is produced in a variety of weights.
Specialty-Eaves Flashings – This self-adhering, polymer-modified bituminous sheet material is designed for special flashing applications along roof eaves and in other areas. It is used particularly in regions where ice dams and water backups are common.
Mineral Surfaced Roll Roofing – This type of roll roofing is used alone as a primary roof covering, most frequently on small or secondary-use buildings such as supply buildings, barns, garden sheds, etc. The top surface of the roll is imbedded with mineral granules.
What are the major low-slope roofing systems?
The two broad categories of asphalt roofing systems for commercial, industrial, and institutional are Built-Up Roofing (BUR) and Modified Bitumen Systems (MBS).
What is Built-Up Roofing (BUR)?
Built-up Roofing (or BUR) is the most popular choice of roofing used on commercial, industrial, and institutional buildings. BUR is used on flat or low-sloped roofs and consists of multiple layers of bitumen and ply sheets. Components of a BUR system include the roof deck, a vapor retarder, insulation, membrane, and surfacing material. The components are assembled at the job site to actually form the built-up roof. At the heart of this roofing system is the roofing membrane, which consists of roofing bitumen and multiple reinforcing plies of roofing felt.
Roofing bitumen is the primary adhesion/waterproofing agent used between roofing plies. Bitumen arrives at the job sit in solid form, but is heated and applied as a liquid. Roofing bitumen may be either a product of petroleum refining (asphalts) or a product of the coal-cooking process (coat tar pitch).
Multiple reinforcing “plies” are asphalt-coated roofing sheets or felts installed in three or more layers to strengthen and stabilize the BUR membrane. These multiple reinforcing felts also make the membrane more pliable and resilient, protect the bitumen from water degradation, and serve as a fire-retarding element in the membrane system.
BUR roofing membranes can be protected from solar radiation by embedding gravel in the bitumen, applying a surface coating, or applying a granular-surfaced “cap” sheet. Light-colored surfacing materials can be used to reflect heat from the building. In addition, surfacing agents can provide additional fire protection.
What are some of the advantages of BUR?
Built-up roofing systems have had a long-standing popularity, due in large part to the success and proven reliability of BUR. The stock of 20, 30, and 40-year old BUR roofs still in excellent condition attests to this fact. Specifically, BUR roofs offer:
Multi-layer protection – the multiple layers of bitumen and bitumen saturated “felts” make a watertight barrier capable of providing many years of reliable protection from the elements.
Thermal Performance – Built-up roofing systems exhibit exceptional resistance to stop the conduction of heat between the exterior and interior of a building, resulting in noticeable reductions in heating and cooling costs.
Fire and Uplift Resistance – Built-up roofing systems are tested through Factory Mutual Research Corporation to meet very strict fire resistance requirements and ensure adequate uplift resistance under extreme wind conditions.
Economy – Compared to other high performance commercial roofing systems, built-up roofing is one of the best investments on the market due to its competitive cost per year of expected service life.
What is Modified Bitumen (MB) or Modified Bitumen Membranes (MBS)?
Modified bitumen membranes (MBS) combine the features of a built-up roof with the added tensile strength from its polymer modification. Using a reinforced sheet that is prefabricated in the plant, modified bitumen systems require a less labor-intensive application and can be applied cross-platform in both commercial and certain residential applications.
A modified bitumen roofing system is composed primarily of polymer-modified bitumen reinforced with one or more plies of fabric such as polyester, fiberglass or a combination of both. Factory surfacing, if applied, includes mineral granules, slag, aluminum or copper. The bitumen determines the membranes’ physical characteristics and provides primary waterproofing protection; while the reinforcement adds strength, puncture resistance and overall system integrity.
Factory-assembled modified bitumen membranes undergo strict quality control standards to ensure uniform thickness and consistent physical properties throughout the membrane. The finished roofing system is usually a two – to four-ply system consisting of a modified bitumen membrane and a base sheet, with additional plies for added strength if needed. The substrate often determines which ply system is best specified.
The finished roofing membrane may consist of one or more modified bitumen sheets, or it may be comprised of a combination of build-up roofing (BUR) felts and one or more modified bitumen sheets. The type of substrate and the performance objective influence the specification of the modified bitumen membrane system.
There are modified bitumen membranes tailored to almost every type of construction design and climate for new roofing or re-roofing of commercial buildings, residential high rises, domes, spires, and most categories of low-slope or steep-roof roofing. Thus, there are a variety of modifiers and types of reinforcements and surfacing available.
Why choose Modified Bitumen roofing systems?
Since gaining acceptance in the roofing industry during the 1970s, the use of modified bitumen membrane roofing systems has increased steadily. Today, modified bitumen membranes are the fastest growing roofing materials in the industry.
Considered a quality “hybrid” system, MBS provides the features of a built-up roof with the added tensile strength and elongation of a modified bitumen cap sheets, as well as the quality assurance of in-plant membrane fabrication uniformity and control, and reduced labor requirements for installation.
In addition, MBS products undergo the same fire and uplift resistance testing standards as BUR, providing the commercial customer full assurance of appropriate fire and uplift resistance.