What is the purpose of a drip edge on a roof?
Is a drip edge necessary? We have complied a guide for all your drip edge questions for shingle roofs. Drip edges are metal flashings that are installed around the edges of a roof to control the flow of water. These metal sheet are usually in the shape of an “L,” and direct water away from the fascia and into the gutters. Without its use, water would get under the shingles causing damage in numerous places of the roof. Your local roofing contractor will tell you that is is a requirement by most building codes in North America to help protect homes from damage. As we always suggest, look for the best roofing company in your area to ensure your roofing work is done properly. Not all work is created equal.
As we stated above the main key purpose of installing drip edge is to direct water away from the fascia. Water droplets stick to one another and to the surfaces they are on, it is designed to work with gravity allowing water to be forced into the gutters. Even if a home has no gutters, water will still be forced away and not collected down the fascia or soffit cavity. Without it water would stick to the shingles, working its way underneath and causing leaks.
Wind driven rain is a serious condition in which the wind forcefully pushes water all around the roof of a home. Each layer of the roofing system is designed to keep the moisture from harming the roof’s deck, which include the shingles, underlayment’s, and ice & water. Strong winds can easily push water upwards and the drip edge must compete to keep the water out. There should be about 2-4 inches of lower flange hanging off the edge of the roof to combat wind driven rain so the roof does not become compromised.
What type of materials are used?
Usually it is made from numerous types of materials such as plastics and metals, the metals must be corrosion resistant or galvanized.
Copper: Many people choose copper because of its aesthetics, it has a beautiful golden color that makes the roof pop.
Aluminum is a very common material used. Although it is not as strong as steel aluminum does not corrode and it is often made in many colors that match many homes.
Galvanized steel is another common material used. Galvanized steel is designed to work wither water and prevent rusting. The preferable type of steel is 24 gauge so it can withstand strong winds.
Plastic, vinyl and fiberglass can also be used but these are harder to find in some areas and are not the best suited.
Drip edge comes in three basic profiles, each profile can be called more than one name so it can be a bit confusing. The C type is in the classic L shape. This type of profile is bent in a 90 degree angle with a lower flange. Type D profile is in the shape of a T, this has a lower flange on the bottom. This type is often times called D-metal or the T style. F type is an extended version with a longer edge, this is used when installing a new over existing shingles and on the rake edges. This type is often called F style or the gutter apron.
The standard sizing of drip is sold in 10.5 foot lengths and also 8ft or sometimes smaller. The overhang length ranges from 2-5 inches, you may find other sizing in your local materials store, but smaller sizing is intended for windows and not a roof.
What color should roof it be?
If your homes trim and fascia are white your local roofing contractor will most likely recommend that the best choice is white so your home is seamless. If you have for instance gray shutters on your home and other pops of gray, then choosing a gray might look nice tying it all together. Choosing a color or any building material is personally preference.
Can you install it on existing roof?
It is most often replaced when a new roof is installed, but it is possible to replace the drip edge at any time. We would not recommend a local roofing contractor who suggests leaving the old drip edge. It is best to replace the it on an existing roof in the warmer months, shingles can become brittle in the cold and break.
Do you need to replace it when replacing the roof?
No you do not have to replace it but you should, the old drip edge is most likely “old” looking and dirty from being outside for so long. If you are making the effort to replace you roof, you should replace everything so the entire roofing system looks nice. Leaving old materials to save a few bucks isn’t worth loosing on the appearance. If you want your roof to last as long as possible, everything should be replaced when doing a re-roof.
How to install:
It is installed different on the eaves and rakes, once the roof deck is prepared the drip edge will be installed before the underlayment. Always consult with your local roofing company before doing any DIY work. Your roof is the most important part of your home, look for the best roofing company in your area to be sure the job is done correctly.
Step one: If you are using a type C, you can install a furring strip which will aide in its performance. A furring edge is a strip of wood that is installed on the vertical surfaces of the house under the roofs edge. When this is installed it keeps the flower flange away from the homes siding to direct water away from the home.
Step two: First install drip edges on the eaves and placing the it down, so that the water will go into the gutters. The flange will point down and away from the roof.
Step three: Using roofing nails, nail every 12 inches, never allowing more than 12 inches without a nail. When placing it piece down, it should never over the first by an inch.
Jon Dominic says
Crisp and clear! Your blog post talks about everything the homeowner needs to know and understand about the purpose of a drip edge on a shingle roof. Good job!