Your home’s roof is made up of more than asphalt shingles. There’s a series of roof components that protect your home from the rain, wind and snow. It is critical to understand all of the parts of a house roof in order to explain a problem to a roofing professional and understand what he or she is talking about when he or she is doing repairs.
Here’s an outline of every term we’ll cover in this article:
Roofs come in all sorts of shapes and sizes, but you only need to know a handful of terms to describe their essential architectural features.
These are the parts of a house’s roof:
The anatomy of a roof, or the layers of a roof, give it structure and protect the home.
5. Roof Frame
Let’s begin describing the anatomy from the top of the roof.
The roof begins with the most recognizable of roof components: the shingles. In the past, wooden and slate shingles were typical; but, for the last 100 years, asphalt shingles have become the most common residential roof covering in North America. Generally speaking, there are three styles of asphalt shingles:
After being applied, shingles need to seal to one another. Though the roofing professional will first secure the shingles to the roof with nails, IKO’s shingles have a heat-activated sealant that will help achieve better wind resistance. After sufficient exposure to warm weather, the sealant will bond the shingles to the course below them.
If your roofing professional applied your shingles in cold weather, he or she might have manually sealed the shingles to provide wind protection until warm weather arrives. Also, IKO offers a high-wind application procedure for our Cambridge™ architectural shingles, which a roofing professional can use to provide an added measure of protection to help meet the challenges of high-wind conditions. Or you can chose a shingle from our Performance line for added wind resistance.
Shingles can also be designed to serve other functions on the roof or to create a unique look.
Learn more in our guide to the different shingle patterns.
Flashing is a thin sheet, usually made of metal, that a roofing professional installs around any vertical surface that intersects with the roof plane, such as the surface of a chimney.
Of all roof components, flashing seems to be the least clear to the homeowner. To understand the need for flashing, think of a chimney. Chimneys don’t have shingles or underlayment, and they punch right through the roof decking into your home below. Chimneys have protection to keep water from rushing in through the top (a chimney cap); but what about the sides? What’s to stop water from running down the exterior of the chimney, wiggling right past the edge of the shingles, underlayment or decking and into your home? Flashing is the answer.
There are many roof flashing applications. You will see flashing installed around other residential roof features, including:
It’s often necessary to install flashing around a roof’s architectural features, the design elements that create the shape of the roof. Architectural features that need flashing include:
Underlayment is a fabric-like barrier, traditionally made of asphalt-saturated felt, but now commonly available as a synthetic. It’s applied directly to the decking and serves a few different functions. Underlayment protects the shingles from any resin the decking may release and serves as a water barrier in case water gets beneath the shingles. It also offers some fire resistance.
Further, underlayment may help prevent “picture framing.” Picture framing is generally the result of the expansion/contraction of the wood panels used for the roof deck. As they move, the deck panels create ridges or bumps in the surface of the roof. These bumps look unappealing and may interfere with the water-shedding function of the roof.
There are different kinds of underlayment, including synthetic underlayments. These underlyaments have become more popular over the last several years because they are lightweight and have printed grid lines that make them easy to install. Additionally, synthetic underlayments may have features you can’t get in traditional asphalt-saturated felt. For example, IKO’s RoofGard-Cool Grey is a lightweight underlayment designed to absorb less heat, providing a more comfortable surface for the shingle applicator.
Ice and water protector is another thin layer of material that is installed beneath the shingles. This material helps defend a roof from ice dams and wind-driven rain, which can drive water up between shingles. IKO’s ice and water protectors are self-adhering and made of modified bitumen. This material closes around nails, providing a watertight seal. Some, like ArmourGard™, also act as vapor retardants, which means they allow very little water vapor to pass through them.
In some climates, it makes sense to use an ice and water protector over the entire roof deck, particularly in high-wind and hurricane-prone areas of the country. However, if the attic does not have proper ventilation, the ice and water protector could make them worse. Even in climates with less severe weather conditions, ice and water protectors can provide an added water barrier for vulnerable areas of the roof, like valleys or the roof’s edge, or around roof features like skylights.
When they build a home, contractors will add a wooden frame for the roof on top of the house. This framing, also called a roof truss, serves as the roof’s skeleton, which the other parts of the roof will all rest on. There are various national and local construction codes that dictate the structure of your roof frame. In this article, we will focus on the parts of the roof above the roof frame.
The basic layers of a roof that we’ve covered so far aren’t enough to protect your home. Water can’t just roll off your shingles and down the face of your house, or your bricks or siding would be damaged. Plus, the water would collect around the base of your home, which could cause foundation issues. So, at the roof’s edge, a series of roof drainage components are installed to protect your home from these potential problems.
First, you have to understand that there are two types of edges on a roof: eaves and rakes. An eave is a horizontal edge where the roof hangs over the exterior wall. A rake is a sloped edge where a roof hangs over the exterior wall. It is essential to handle the drainage from a roof at the eave properly and protect against wind-driven rain at the rake.
Here are the parts of a roof edge:
All of these roof components work together as a system to drain water away from your home and protect it from the elements.
Understanding and being able to name the parts of your roof are helpful when you get your roof repaired or try to describe a problem to your roofer. Plus, if you’re building a custom home, knowing the parts of a roof is invaluable. You can use the architectural parts of a roof to describe what shape you want your new roof to be.
There’s more to learn about the shape, structure and edge of residential pitched roofs; discover it by visiting IKO’s Roofing 101. Or, if you need help with one component of your house’s roof, contact a roofer in your area through our Contractor Locator.
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