by Nick Gromicko, CMI®, Maggie Aey and Kate Tarasenko
What is a shingle gauge?
A shingle gauge is a tool used to measure the thickness of a roof's asphalt composition shingles. That measurement is used to estimate the level of warranty for the shingles. The shingle gauge is a handy device for property owners and managers, as well as insurance claims adjusters, roofing contractors, and home inspectors.
Shingles are exposed to weathering conditions that include sunlight, wind, hail, snow, rain, and temperature variations, all of which degrade the shingles over time and reduce the composite materials’ thickness.
Being aware of a shingle’s warranty level can help in the purchase of comparable replacement shingles, as well as in determining whether the shingles are wearing according to their advertised service life, and not substantially sooner.
Laminate Shingles and Warranty Changes
Laminate shingles are also known as architectural or dimensional shingles. They’re a more durable type of asphalt composite shingle. They’re created with a heavy base mat and multiple layers of asphalt sealant that reinforces the shingles’ waterproof capability. Laminate shingles have a 3-dimensional appearance and can resemble premium roofing materials, including wood and slate.
In 2011, most shingle manufacturers announced that all laminate asphalt shingles installed after January 1, 2011, are automatically covered by a limited lifetime warranty, although neither their composition nor the manufacturing process changed. Prior to 2011, manufacturers typically sold asphalt composite shingles graded by warranties in five- and 10-year increments.
Technological advances weren’t the driving factor behind the warranty change. In a 2011 statement announcing a new limited lifetime warranty for laminate shingles, manufacturer CertainTeed stated, “After having surveyed a cross-section of contractors and distributors, we have decided to demonstrate the strong confidence we have in the quality of our products.” It’s also safe to assume that the upgraded warranty was implemented as a marketing tactic because warranty coverage is considered a valuable factor by both property owners and contractors when deciding which shingles to purchase.
The "After 2011" or Short Gauge
The short gauge can only be used to estimate warranty levels for fiberglass asphalt 3-tab shingles installed after January 2011. A fiberglass asphalt 3-tab shingle has one tab size and shape. The 3-tab shingle is also thinner than laminate shingles, and is 20% to 40% cheaper. Due to the manufacturing warranty changes in January 2011, the short gauge excludes laminate shingles because their thickness no longer fits into as many measurable categories. The short gauge can be used to estimate the warranty level for fiberglass asphalt 3-tab shingles in increments of 20, 25, 30 and 35 years, as well as the lifetime warranty.
The "Before 2011" or Long Gauge
The long gauge can only be used to estimate the warranty level for 3-tab or laminated shingles installed before January 2011. The estimated warranty levels for 3-tab fiberglass are 20, 25, 30 and 40 years. The estimated warranty levels for 3-tab organic shingles are 20, 25 and 30 years. Both 3-tab fiberglass and 3-tab organic shingles are made from asphalt, but they differ in their base mats. The base mat of a fiberglass shingle is made of fiberglass, while the base mat of an organic shingle is a wood product. The estimated warranty levels for laminated shingles installed before January 2011 are 30, 35, 40 and 50 years.
Shingle Gauge Exclusions
Short "After 2011" gauges cannot be used to estimate the warranty level on shingles installed before January 2011, and long "Before 2011" gauges cannot be used to estimate the warranty level for shingles installed after 2011. The openings of the two shingle gauges differ in size.
Additionally, warranty levels cannot be estimated using a shingle gauge on shingles made with modified asphalt, also known as impact-resistant shingles. Modified asphalt shingles are made using a transparent thermoplastic polymethacrylate (PMA), or synthetic rubber styrene-butadiene-styrene (SBS). Modified shingles typically offer enhanced weathering and impact resistance. However, most asphalt shingles, such as 3-tab and laminate shingles, are made using blown asphalt.
Most lifetime warranties are valid for roofing materials installed on single-family homes. Depending on the manufacturer and product, a lifetime warranty for a commercial structure – such as a condominium, school, church, or industrial building – is typically covered by a 40- or 50-year warranty. It’s important for property owners to read their warranty documents thoroughly to be aware of their various conditions and limitations.
Estimating the life expectancy of roofing materials lies beyond InterNACHI’s Standards of Practice. However, inspectors may choose to exceed the SOP and offer this value-added information as part of their services. It can assist property owners in making a more informed decision as to whether they need to contact a roofing professional.
Inspectors should also remember that safety comes first, so they should walk a roof only when it is safe to do so, and always use standard precautions and safety equipment to protect both themselves and their client’s property.
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