When looking at a roof from down below, it’s easy to assume that the asphalt shingles you see from the street are all that make up the roof. However, a roof is made up of several different materials and components that all come together to form a complete roofing system.
On average, we work on over 750 roofs per year. Much like the homeowners we work with, you probably have questions about your asphalt roof replacement. What materials are used? Why do you need them for a successful replacement? To help you better understand, I’m going to break it down for you.
By the end of this article, you'll know ten different materials that are included in an asphalt roof replacement. Let’s get started.
1. Asphalt Shingles
Featuring a durable asphalt coating that is resistant to moisture, inclement weather, and fire hazards, asphalt shingles are designed to protect your home with minimal maintenance.
Their durability and longevity make them the roofing material of choice for the vast majority of homes in North America. However, one of the biggest reasons homeowners tend to choose asphalt shingles is because of their versatility. There are three categories: 3-tab, dimensional, and luxury shingles.
Starter shingles are asphalt strips that are laid on the roof before the actual shingles are installed. They are designed to cover shingle joints at the eaves to help waterproof your roof. They’re typically installed along the edges of the roof to greatly improve wind resistance by sealing finished shingles at eaves and rakes.
Starter shingles are generally covered with natural roofing granules. They’re also a generic rectangular shape, so they’re really compatible with almost any overlying shingle style.
3. Roof Decking
Roof decking is plywood or OSB boards that connect the roof to the frame of your home. Shingles and other roofing components are all installed on top of the decking.
When you get a roof replacement, you might have to replace your roof decking. Because it lays under the shingles, it can be difficult to tell its condition until the old roof has been torn off.
There are a number of signs of roof rot, such as moldy smells, wet walls, and consistent leaks even when it’s not raining. These symptoms are usually caused by bigger problems such as ice dams, clogged gutters, and other issues that cause water to pool on your roof and create rot in the first place.
If your contractor finds that the decking is rotten, sprinkled with black mold, or shows heavy water damage, it will need to be replaced. However, decking isn’t usually completely replaced; only the sections with such conditions will need replacement.
Roofing underlayment is a waterproof or water-resistant material laid directly on a roof deck before any other roofing materials are installed.
Wind-driven snow and rain can trap water under your shingles, exposing your deck and the interior of your home to moisture damage, leaks, mold, and rot. Underlayment provides an additional layer of protection that shingles alone can’t offer.
If you want the safest, most water-resistant roof or to extend the lifespan of your roof, be sure to include underlayment in your installation. Preventing water infiltration before it becomes a leak is always easier than dealing with costly repairs or damage.
5. Ice & Water Shield
Ice and water shield is a self-adhering, rubberized membrane that protects your roof from leaks caused by heavy storms, wind-driven rain, and ice dams.
There are several areas on your roof that are especially susceptible to leaks. For example, homeowners who live in colder climates are potentially more at risk when it comes to ice dam formation.
Ice dams form because of the continuous melting and freezing of snow caused by heat escaping from your home. When the snow melts, this melted water runs down until it reaches the unheated bottom edge or soffit area of your roof. Once this melted water freezes, it becomes an ice dam.
Without the proper roofing ice & water shield, the water that builds up behind an ice dam can leak into your home and cause damage to your walls, ceilings, and insulation.
When water can’t move past an ice dam, it typically moves under the shingles because it has nowhere else to go. Ice and water shield protects shingles by creating a watertight seal between them and the roof deck, helping to prevent water penetration.
Let’s go over some of the most crucial areas where ice and water shield needs to be applied:
Eaves & Roof Edges- The eaves and roof edges are especially vulnerable to ice dams and will form near the gutter. An ice and water protector is critical to have in these areas to help direct water into the gutter rather than penetrate through the nails and into your roofing structure.
Chimneys, Vents, Skylights & Flashings- Installing an ice and water protector is essential in these areas specifically to protect your roof from wind-driven rain. Skylights, which penetrate the roof deck, will also require an ice and water protector.
Valleys- A valley is an area where two different roof slopes come together. This creates a “V” shape that allows rainwater to flow freely down your roof and into your gutter system. The large volume of rain that’s channeled through the valleys can cause wear and tear that leads to damage. Because of this, ice and water shield needs to be installed around the valleys to protect them from the constant flow of water every time it rains.
Roof flashing is a thin metal or aluminum material that roofers install to direct water away from vulnerable areas on your roof. It’s installed directly underneath the shingles to redirect the water to another location.
These are some of the most common areas that need flashing:
Side walls and front walls (the roof surface that joins the wall)
Roof penetrations (plumbing vents, kitchen vents, and skylights)
Roof edges (eaves and rakes)
During reroofing, it is typically good to replace each and every piece of flashing because old flashing may begin to fail before the new roof’s lifespan is over. On the other hand, there are limited situations where a roofer may choose to reuse your flashing, such as if the flashing can’t be removed without damaging your siding.
7. Drip Edge
Drip edge is a type of aluminum flashing designed to protect your roof from water damage. It attaches over the top of fascia boards and the edge of the roof beneath the roofing. Drip edge should be installed on the eaves, rakes, and roof gables.
Their bent design allows them to keep water from flowing backward towards your roofing components. This prevents erosion of the fascia board by keeping it dry and preventing water from getting underneath your roofing components.
Drip edge must be included in your roof replacement. Be aware, some contractors will leave it off their estimates to make it look like they’re giving you the best deal. Read this article if you want to learn how to identify a high-quality roofing estimate.
8. Roof Boots
Have you ever wondered what those small pipes sticking out of your roof are? What do they do? Sometimes referred to as vent stacks, these pipes are used to reduce air pressure in your plumbing system by safely releasing sewer gases outdoors.
Roof boots are synthetic rubber boots that wrap around the base of these pipes. They create an airtight seal that stops water from following the pipe down through your roof and into your home. In order to effectively prevent leaks, roof boots must be replaced every time you get a replacement.
Cracked pipe boots are one of the most common causes of roof leaks. To catch a cracked pipe boot before it becomes a problem, it’s crucial to have them inspected regularly through roof maintenance. Read this article to learn more about developing your roof maintenance routine.
9. Ridge vents
A quality installation will also help to ensure that your roof is properly ventilated. As the uppermost part of your home, your attic is sandwiched between indoor and outdoor temperatures. When these elements clash, condensation and moisture are bound to follow.
Ridge vents are installed during your replacement to help your attic breathe and prevent too much moisture. They also help to avoid leaks caused by large fluctuations in temperature.
10. Ridge Capping
Ridge cap shingles are specifically designed to be installed on the ridges of roofs. They’re typically pre-bent and thicker than regular roof shingles that tend to crack when folded over a ridge. Their shape also makes them more efficient in shedding water and debris.
Additionally, ridge cap shingles have more adhesion and a thicker nailing area compared to regular shingles. These qualities help prevent shingle blow-offs and tears near the nailing hole.
So, What's Next?
Now that you know all of the components included in an asphalt roof replacement, you may be wondering how long the whole process can take.
Replacement times can vary according to the type of shingles you choose, the complexity of your roof, and even current weather conditions. Learn more about how long your replacement could take here.
Our best piece of advice for protecting your home during a roof replacement is to hire an experienced roofer. We aren’t telling you this because we’re trying to sell you, but because we have seen too many homeowners not get the best roof possible. Read this article to learn more about the benefits of hiring an experienced contractor.