November 18, 2016

What is a Roof Drip Edge and Why Is It Necessary?

Almost every shingle manufacturer shows a metal roof drip edge in their installation instructions. The Asphalt Roofing Manufacturers Association “Residential Asphalt Roofing Manual” indicates that roofing drip edge be included in the construction of a shingle roof. Yet, many residential roof installations do not have them installed.

Unfortunately, the drip edge is often omitted from a bid unless the scope of work specifically requires it, normally as a money-saving tactic. When the drip edge is included, the type of metal, gauge and dimensions are rarely included.

Many roofers believe the roof drip edge is unnecessary as long as the shingles are extended far enough over the edge of the deck into the gutters, something that is not true. The fact is you need a drip edge on roof edges for many different reasons.

Critical at Eaves

The most critical location for a roofing drip edge is at the eaves of your house as this is where the most drips occur. Rake edges should also get drip edge as well as at the edge of the felt underlayment. Felt can be installed on top or underneath the metal.

The edge of the roof that catches the most water needs the best protection possible. Shingles that are extended more than three-quarters or one-inch over the edge of the roof will bend, eventually fracture and break. If there is no metal drip edge, water may not cascade off the eaves into the gutters, allowing water to get into the substrate by turning up under the shingle.

Damage Under Shingles

If water gets under your shingles, it can cause short-term staining, but more importantly, it can cause long-term deterioration of the roof deck and along the fascia board.

If the water damage is allowed to exist for a prolonged period, it can also affect the ends of the roof joists and trusses. Eventually, you may develop leaks and damage inside your home that could be extremely costly to repair.

Not a Money Saver

Ironically, not including a drip edge on roof bids is often done as a money-saver but can lead to catastrophic damage later. This leads to extensive repair costs both inside and outside the home.

In some cases, a builder may rush the roof and cover it with felt in order to speed the interior work. In these cases, the builder may hurriedly run a cutter along the roof deck, but because they are rushing, they often do not do so in a straight line. This causes the edge of the felt short of the edge and, when fascia board is added later, the felt is even further from the roofing drip edge.

If you are in need of a new roof or are planning to build a new home, contact us to learn more about roofing, shingles and drip edges. You can speak to one of our knowledgeable customer service representatives by calling or completing the easy form online.

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