20 Apr Roofing Underlayment 101: An Overview of Roofing Underlayment
This blog is an overview in a series about roofing underlayment. You can find detailed breakdowns of the importance of each element individually by clicking on the links below:
Essential Elements of a Roofing Underlayment System:
Roofing underlayment is a water-resistant material on your roof that provides it with an added layer of protection against outdoor elements. Not only does it help against roof degradation but it also prevents it from happening in the first place. In this blog, we’ll be listing down the main elements of underlayment for roofs.
Essential Roofing Underlayment Elements
1. Roof Deck
The roof deck is the first and one of the most important elements to consider in the roofing process. For most home applications, 3/8″ plywood is used as a standard as it provides better resistance against moisture compared to other common alternatives such as OSB and board style roofs.
Before installing an underlayment, it is vital to check for and replace any damaged, misaligned or rotted boards on the roof deck. The roof deck should also be clean and any unleveled surfaces remedied before beginning with the underlayment.
2. Drip Edge
A drip edge is an aluminum flashing that is installed at the bottom of all roof areas to guide water into the trough and seal off the base of the roof. It protects against ice damming and closes the gap between the fascia and the roof so animals can’t burrow into the attic. A drip edge also grants support to the integrity of the shingles that overhang past the roof. While you can find many types and profiles of it on the market, the 1×3 inch is the standard for most residential sloped roof
3. Ice and Water Shield
Shingles alone can only do so much to protect the decking against moisture intrusion into a compromised area of the roof. An ice and water shield is an adhesive layer that seals off the most vulnerable areas of your roof such as along its base, roof-to-wall joints, chimneys and valleys.
4. Synthetic Underlayment
Arguably one of the most crucial roofing underlayment elements, synthetic underlayment acts as a buffer between the shingles and the roof deck. Good synthetic underlayment is extremely tough and durable, both acting as a second line of defense against elements as well as eliminating the risk of water seepage into the roof deck. Synthetic underlayment also keeps the shingles up off the roof deck and gives them a smoother surface to lie on which helps prolong the lifespan of your roof.
Occasional Underlayment Elements
A valley is formed when 2 different sections of roof meet at an exterior angle of fewer than 180 degrees. Valleys act as a channel that guides the water flow off your roof. Valleys come into two main styles – closed and open. In closed valleys, the primary roofing material e.g. the shingles is used to cover it while, in open valleys, a galvanized metal piece is installed when the roof sides intersect. Open valleys tend to be more resilient against water flow over time as shingles erode whereas metal does not.
6. Step Flashing
While not common, it is recommended to have step flashing installed in any area where shingles intersect against a wall or any vertical surface like a chimney. It helps seal off the gaps in the roof that result from any irregular protrusions. Each shingle requires its own piece of step flashing.
In need of a roofing company in Hamilton and surrounding areas? Consider hiring our expert team of roofers for the task. For a free quote or any queries, call 905-746-5792.