Is time to replace the roof on your home? Are you trying to figure out everything you roof needs to stay leak-free for decades?
If you’re like most homeowners, you probably don’t know much about your roof. This is understandable because you shouldn’t have to think about it until there’s a problem or it’s time for a replacement.
But when the time does come for a new roof, there’s a lot that goes into it. After all, a roof is much more than the shingles or main material you see.
There are different components that comes together like a puzzle to prevent water intrusion. But what are these components? And what do they do?
For over 35 years, Bill Ragan Roofing has helped homeowners understand everything that actually goes into making a quality roof system. So, let's look at all the materials and components that make up a residential roof system.
By the end, you'll know the what, where, and why for:
Roof decking (also called roof sheathing) is the wooden boards (plywood or planks) that make up the foundation that the rest of your roof is installed on. There are two types of roof decking: plank decking and sheet decking.
Plank decking is made up of elongated and rectangular wooden boards that come in two different sizes, 1x6 or 1x8, depending on the span of the rafters. Sheet decking (or sheathing) is flat sheets of wood, either plywood or OSB, that are much wider than planks.
OSB (oriented strand board) is made up of wood chips/strips compressed together to form a flat 7/16” sheet, while plywood comes in several different thicknesses (⅜”, ½”, ⅝”, and ¾”). If your roof’s decking is rotten or can’t handle the installation of a new roof, it’ll need to be replaced.
However, your roofing contractor won’t know if or how much will need replacing until your old roof is torn off during your roof replacement.
Drip edge is metal flashing installed at the roof’s edges (eaves and rakes) to keep water from getting underneath your roofing material and components. Without it, your fascia board and roof decking will rot from extended exposure to water.
Installing drip edge at the rakes and eaves is actually a required building code, and it must be installed correctly as well. Unfortunately, I see too many roofs without drip edge because some roofing contractors leave it off to keep their prices lower or from pure laziness. I
f your roof estimate doesn’t have a line item for drip edge, you need to bring it up or find another roofer altogether.
Roof underlayment is a material installed between your roof decking and your roofing material (asphalt shingles, metal roof, etc.) to provide an extra layer of protection. If water does get underneath your roofing materials, underlayment is there to protect your roof decking.
There are two types of underlayment: felt and synthetic.
Felt underlayment has been around the roofing industry longer than synthetic and comes in 15 lb. and 30 lb. rolls. Both types do the job, but 30 lb. felt underlayment is thicker, stronger, and less likely to tear than 15 lb.
Synthetic underlayment is made out of woven/spun polyethylene or polypropylene, which means it won’t hold moisture. It’s more durable, holds nails better, and repels water better than felt underlayment.
Felt isn’t a bad choice, but I recommend spending the extra money for the functionality and better water protection synthetic underlayment offers.
Ice and water shield is a waterproof membrane that protects your roof from ice and water damage if it gets under your roofing material. But unlike underlayment, it’s installed on/around certain problem areas that need added protection instead of over the entire roof deck.
These areas include roof valleys, around penetrations, and roofs that have a 2/12, 3/12, or 4/12 pitch. If you live above the snow line in the US, there’s also a building code that requires installing 2 rows ice and water shield along the edges of your roof to prevent leaking from ice damming.
This is considered an "upgrade" for areas like Middle Tennessee to prevent ice damming leaks when we get heavy snowfall.
Starter shingles are an asphalt-based roofing accessory used as the first course of shingles on the edges of asphalt roofs. They look like shingles without the tabs but are thinner and pre-cut for easy installation.
Starter shingles are installed along the rakes and eaves over the underlayment before the actual shingles are installed on top of them. While this is mainly for asphalt shingles, every roofing material has a starter component.
Your roofing material is the top layer that makes up the bulk of the roof system you see from the outside. There are plenty of options, but the most popular residential roofing materials are asphalt shingles, standing seam metal roofing, cedar shake roofing, synthetic roofing, and slate roofing.
The roofing material has a huge impact on the cost, aesthetic, lifespan, and warranty options of a new roof. So, it’s important to pick the right one for you, your home's aesthetic, and your budget.
Ridge capping is installed where two slopes meet to completely seal your roof system at the very top. It will be made of the same material as the main roofing material, except that it’s pre-bent to form perfectly on a roof’s ridge.
No matter which material you choose, your roof needs the associated ridge capping. While ridge capping is needed on the ridge, there's also hip capping on hips.
Roof flashing is a metal material that directs water away from certain areas (walls, chimneys, roof valleys) of your roof. Even though all the components in this article are important, roof flashing is probably one of the most important.
Roof flashing can be any metal type, but aluminum, steel, and copper are the most common options. While roof flashing usually outlives the other components, it's always recommend replacing it when it’s time for a new roof if the existing metal is questionable.
This is simply to prevent future problems and ensure everything installed on your roof is the same age.
Roof vents allow your attic and home to breathe properly by pulling fresh air through intake vents before pushing it out of exhaust vents. There multiple roof vents to choose from, it depends on the the type of ventilation system (active and passive) you have or want.
If you have an active ventilation system, you’ll choose turbine vents, power vents, ridge vents with a baffle, or solar-powered vents. For a passive ventilation system, you choose from static vents (box vents), ridge vents without a baffle, or gable-end vents.
I recommend an active ventilation system for performance reasons. No matter what, your roof’s life will be cut drastically short if your attic isn't vented properly and your energy bills will be higher.
A pipe boot (also called roof boot) is a type of flashing that goes around the base of the pipes coming out of your roof. Without them, water leaks down the pipes into your attic and home.
The most common type of pipe boot used on roofs today is a synthetic rubber called neoprene. But just know that neoprene pipe boots will need replacing every 10 years or so once cracks form.
However, they’ll be cheaper than copper (or another metal), more durable than plastic, and won’t attract animals like lead.
Now you know the 10 materials that must be included in your roof replacement. If your roof is missing even one, you’ll be looking at roof leaks in the future.
So, use this list while looking at your estimate to ensure everything your roof replacement needs is included before signing. However, learning what gets replaced is just a small piece of the information you need to know when getting a new roof.
After all, a roof replacement is a large and expensive home improvement project. The last thing you want is to be taken advantage of by a bad roofer or make the wrong decisions.
That’s why I wrote another article breaking down the things every homeowner needs to consider before replacing their roof.
Check out 7 Things to Consider Before a Roof Replacement to start the process with the right mindset and information needed for the best experience possible.