As important as the main body of your roof is, the proper completion of the edges are also equally important in assuring your roof functions at its best. Everything from the length of the shingles over the gutters, to whether your house has gutter guards and Drip Edge, or just one or the other all plays into this arrangement.
Correct Gutter Overhang
In considering this balance the following will be examined:
- Gutter Guards and Drip Edge.
- Shingle Length Over Gutters.
1. Gutter Guards and Drip Edge
Drip Edge with Improper Roof Overhang
Gutter Glove Gutter Guards
The most ideal arrangement would be to have both gutter guards and Drip Edge on a house. This is because Drip Edge goes from the roof and down the Fascia, thus protecting water from being able to get in between the Fascia and penetrate areas it should not be in. The other advantage to Drip Edge is it helps to guide the water over the roof and directly into the gutters.
Gutter Installation Diagram
Gutter Guards on the other hand are traditionally looked at as a tool that strictly keeps debris out of the gutters. While this is certainly an essential purpose for gutter guards their functionality can be much more than that. Because of how the gutter guard is installed against the Fascia they will offer a certain degree of reinforcement for the roofline. As a result a stronger roofline helps to define the path water should travel down and again help to direct it into the gutter.
Gutter Guards do not have the same protection to keep water from going up under the Fascia that Drip Edge does by directly blocking it, but they certainly can help to limit those chances by providing the roof reinforcement.
Ideally a roof would have both Drip Edge and gutter guards to achieve the best possible chance of preventing water damage. However, it can be difficult to install gutter guards up against Drip Edge since they overlap some of the same area. So while not the first choice, it would be an acceptable practice to have only gutter guards in place of Drip Edge.
2. Shingle Length Over Gutters
When considering the path water takes over the roof and into the gutter the placement of the shingles themselves is an important factor.
Shingles Sagging from Overhanging to Far into the Gutter Space
Starter strip should always be placed down around the perimeter of the roof line first and should overlap the roof by ½” to ¾”.
It is important to check and roof and make sure that Starter is there. This is because Starter plays a large role in the theme of preventing water from running off in the wrong direction. Starter strip covers the shingle joints at the eves while also improving wind resistance on the edges of the roof adding to the durability of the roofs edge.
When applying the shingles to the edges it is important to make sure the shingle has an appropriate overlap to assure water is directed down into the gutters and not into the roof decking.
Standard practices says to overhang the shingles by the same length as the starter, so about ½” to ¾” (as long as there is a Drip Edge present to protect the Fascia). If there is no Fascia it is safer to overhang the shingles by 1” to 1.5” just to make sure the water is directed to the right place. It is critical to be sure not to overhang the shingles to much though, or you risk the shingles being susceptible to wind blow off.