As anyone who lives in the Pacific Northwest knows, it is important to have a good roof on your home to protect it from the constant downpour that occurs nine months out of the year. But how many of us really know what's going on under our shingles?
In this post, we're going to peel back the layers to help you understand the different parts of a roof and their functions in keeping your home safe from leaks and ice dams.
First, check out this helpful graphic from CertainTeed:
There are six main elements to a roof, as you saw above. But before any of that goes on, there is a plywood deck that acts as the base for the roof. This needs to be carefully inspected when your roof is being replaced to make sure there are no deficiencies and that none of it is rotting.
1. Waterproof Underlayment
What is it? A sticky underlayment that goes on the edges of the roof: the valleys, the hips and ridges, the rakes, and the eaves, as well as around any roof penetrations.
Why do you need it? It acts as a barrier to prevent water and ice from building up in the eaves and creating an ice dam.
Why WinterGuard? CertainTeed's WinterGuard® underlayment features a standard adhesive bottom but can be repositioned before deck adhesion. It is available in three finishes: sand, granular, and high tack/high temperature (for keeping shingle, metal, slate, and tile roofs from getting too hot in warmer temperatures). WinterGuard is a "composite material of asphalt polymers, formed into a rolled sheet. The asphalt makes it vapor-tight, and the polymers make the asphalt elastic and sticky", meaning it seals around nails that are driven through it. Check out this video to see WinterGuard in action.
2. Water-resistant Underlayment
What is it? This is the underlayment that covers and protects the bulk of your roof.
Why do you need it? Having a water-resistant, but not waterproof, barrier allows moisture to pass through but not water itself. This is what protects your home from anything that gets past the shingles themselves.
Why DiamondDeck? CertainTeed's DiamondDeck® underlayment is synthetic, made of felt that's been saturated with a asphalt and fiberglass blend. It is scrim-reinforced to improve the protective surface and fully-adhering, meaning less wrinkles for a cleaner, flatter roof surface. An excellent choice for Northern climates, DiamondDeck withstands high winds, so if shingles get blown off, you don't actually need to replace them for up to six months. DiamondDeck holds up better and longer, giving it great value for the cost. You can watch this video to see DiamondDeck as it's applied to a roof.
3. Starter Shingles
What is it? These are the first shingles to be laid down, hence the name "starter," and they line the edges of the roof.
Why do you need it? Starter shingles are laid differently than normal shingles, defending the rest of the shingles from wind uplifts along the edge of the roof.
Here's another way of looking at the layers:
4. Roof Shingles
What is it? These are what most laymen think of when they think of a roof. They are made with a base material, a coating asphalt, a mineral filler, and finally a surfacing material like mineral granules.
Why do you need it? Shingles are the first line of defence for your roof and home.
Why CertainTeed? CertainTeed makes architectural shingles, meaning they are significantly sturdier than the 3-tab shingles of the past. They also offer more color options than their competitors and most people prefer their aesthetics to other shingles. In 2005, CertainTeed won the Professional Remodelers Best in Class award for their superior quality roofing system. You can watch CertainTeed shingles being made here. CertainTeed also offers shingles made with their StreakFighter® Algae-Resistant Technology, which you can read about here and here.
5. Hip & Ridge Caps
What is it? Hips and ridges, as you can see in the diagram above, are the peaks of a roof. They get capped, and the caps then get covered with special shingles to match the roofing shingles and give a nice, finished look to the roof.
Why do you need it? In order to ensure proper attic ventilation, which we'll explain more in a moment, there should be a 1" gap in the roof at the hips and ridges down to the plywood deck. This then gets covered by a ridge vent to allow proper circulation for warm air coming up from out of the attic. They also add another layer of protection to keep water from getting under the shingles and to keep the wind from blowing your roof off.
6. Roof Ventilation
What is it? This should really be the number one thing because a lot of it happens before any shingles get laid down. Heat rises, so having proper ventilation is critical to protection your home. This is often in the form of ridge vents (see above) that allow warm air to leave the attic without allowing the outside to get inside.
Why do you need it? Roofs need to be properly ventilated for a number of reasons: it keeps the framing, insulation, and plywood from being damaged or rotting, and it helps combat potential mold and mildew problems. A properly vented roof will give the shingles a longer life expectancy as well. You can learn more about ventilation here, here, and here.
It is also vital to make sure your roof is properly flashed with drip edge and step flashing to protect the home in the seams of the roofing materials and around the roof's edges.
You can watch a full CertainTeed Integrity Roof System® Installation here.
We are a Shingle Master Certified company partnering with CertainTeed Roofing Products to bring the you quality roofing products and installation you deserve. Our Shingle Master Certification allows us to offer a Sure Start Plus 4 Star 50-year warranty.