There are a wide variety of roofing types and materials, and every region of the U.S. tends to favor one type of roof over another as weather conditions and home styles vary. In this article, we’ll explore 5 popular types of roofing: Asphalt Shingles, Ethylene Propylene Diene Monomer (EPDM), Rolled Asphalt, Slate, and Metal.

Asphalt Shingles

Asphalt Shingles

Asphalt shingles are a popular choice for homes with steep roofs. The steepness, or pitch, of a roof is measured by how much it rises over a certain horizontal distance. For instance, a 1:12 pitch is almost flat, rising just 1 foot for every 12 feet horizontally, whereas a 12:12 pitch forms a sharp 45° angle.

These shingles are typically used on roofs with a pitch of 4:12 or greater. However, some manufacturers also approve them for roofs with a 2:12 pitch, provided a special layer like an ice and water shield is placed between the roof's base and the shingles. The flatter the roof, the higher the chance of water leaks or wind damage. An ice and water shield adds an extra layer of protection against such issues.

There are two main types of asphalt shingles: the flat 3-tab and the architectural style. Until about a decade ago, 3-tab shingles were most common, lasting anywhere from 15 to 30 years. However recently, architectural shingles have become the new norm for new roofs and replacements, with 3-tab shingles becoming less common, though still produced. Architectural shingles have a minimum lifespan of 25 years, with some varieties reaching 40 years or more. The lifespan of these shingles often depends on the thickness of the shingle, with longer-lasting types having a thicker base and more asphalt granules.

When it comes to building standards, up to two layers of asphalt shingles are allowed. However, adding a new layer over an old one can significantly increase the weight on the roof's structure. This might necessitate additional attic ventilation, as a hotter attic can affect the shingles' performance and potentially void their warranty. It's also worth noting that layering new shingles over old ones may shorten their lifespan. For example, a new 30-year layer over an old one might only last around 15 or so years. While layering saves money initially, it may not be cost-effective in the long run.

For roofs with architectural shingles, it's recommended to use only ridge shingles or appropriately cut and color-matched 3-tab shingles at the roof's ridge. Using architectural shingles here is not advised as their design can lead to wind damage. This installation guideline is typically outlined in manufacturers' instructions and warranty terms.

Ethylene Propylene Diene Monomer (EPDM)


Ethylene Propylene Diene Monomer (EPDM), often referred to simply as 'membrane', is a popular material for flat or low-pitched roofs. It's important to note that even 'flat' roofs should have a slight incline, typically 2:12 or less, to ensure proper drainage.

For most flat roofs, EPDM is installed in multiple sections, with rigid foam panels placed underneath for support. The seams, where these EPDM sections meet, are bonded together with a special adhesive to ensure a watertight seal. Additionally, EPDM strips are used along the roof's edges and around features like vents to prevent leaks. When EPDM reaches vertical structures like chimneys, walls, or parapets, it's crucial to extend the material up approximately 12 inches on these surfaces. Termination bars are used at these junctions to further prevent water leakage.

In residential settings, EPDM is typically black and comes in thicknesses of either 0.045 inches or 0.060 inches. The material wears down at a rate of about 0.001 to 0.0015 inches per year. This means that a well-installed and maintained EPDM roof with a thickness of 0.060 inches should have a lifespan of at least 40 years.

Rolled Asphalt

Rolled Asphalt Roof

Rolled asphalt is a great alternative to EPDM for flat roofs. Like the material used in asphalt shingles, rolled asphalt differs in that it comes in rolls and is applied using a hot torch instead of nails. These rolls are typically 39 inches wide and are slightly overlapped during installation to ensure coverage.

The expected lifespan of rolled asphalt roofing is around 8 to 15 years, which can vary depending on how well it's installed and maintained, as well as the roof's pitch and the quality of the material used. One factor to consider with low-pitched roofs is that they tend to retain sunlight and rainwater longer, which can accelerate the deterioration of the roofing material. To extend the life of a rolled asphalt roof, it can be resealed with a UV silver coating. Please note that this coating isn't meant to waterproof the roof but rather to reflect UV rays that can break down the asphalt over time. As the material ages, you may notice the asphalt granules beginning to loosen. Among the various types of flat roofing options, rolled asphalt roofs are generally the most economical choice.

Slate Roof

Slate Roof

Slate roofs, a classic feature of older homes, come in hard and soft varieties. Sourced from mined rock, slate is known for its durability. Each slate tile is typically secured with two nails. However, over time, if one nail rusts and fails, the remaining nail might cause the slate to pivot, creating a hinge-like effect.

Slate's color varies based on its mining location, with Vermont being a common source, though other states like Pennsylvania also have slate quarries. Unlike asphalt shingles, slate can't be bent, making it challenging to ensure watertightness over roof ridges or hips. To address this, metal strip flashings are often used in these areas to prevent leaks.

With proper maintenance and timely repairs, a slate roof can last incredibly long – over 75 years and sometimes even 100 or more years. Hard slate typically outlasts soft slate as it's less prone to water absorption and warping. On roofs older than 50 years, mismatched slate tiles are a common sign of past repairs, as finding an exact color match for older slate can be difficult or even impossible. This is due to slate's color being dependent on its original quarry.

When inspecting an unfinished attic beneath a slate roof, signs of past leaks and even tiny spots of daylight are not uncommon. Annual inspections by roofers with specific training and expertise in slate roofing are ideal for maintaining these roofs' integrity. Additionally, there are asphalt-based and rubberized shingles available that mimic the look of slate for those who like the look of slate but a more affordable alternative.

Metal Roof

Metal Roof

Metal roofs have a very long history – they are known for their durability and can be made from various metals like copper, tin, and aluminum. Each type of metal has distinct characteristics in terms of wear and tear and cost. Copper, for instance, is often the most expensive option among these.

Over time, the exterior coating of these roofs can deteriorate, exposing the underlying metal to rainwater, which can cause rust, holes and leaks. Repainting the roof can be an effective solution and maintenance routine. The ideal time for repainting a metal roof is when you first notice a small amount of light rust. Modern metal roofs often come with paint that's been baked on in the factory, enhancing their durability.

With proper maintenance, a metal roof can last over 40 years. It's important to leave the upkeep of these roofs to professionals who are specifically trained in working with metal roofing materials. Their expertise ensures that the roof remains in good condition for as long as possible, so you get the most out of your investment.

Being familiar with the popular types of roofs proves beneficial when needing a roof repair or replacement. Get to know your roof and its history with a Roof Inspection.

Author Bio:

WIN Home Inspection

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