What is a drip edge on your roof (and why do you need one)?

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• Eaves – Eaves are the horizontal edges of the roof that hang out at lease few inches past the wall. Gutters are typically installed at the eaves.
• Gable end – Usually triangular, the gable end is the outward-facing wall of a house where the two slopes of a pitched roof meet to form a ridge.
• Rake edge – The rake edges are the sloped edges on the gable ends of the roof. Rake edges typically don’t have gutters.
• Fascia – The fascia is the outward-facing, horizontal board that runs along the edge of the roof.
• Soffit – The soffit is connected perpendicular to the fascia on the underside of the eaves. Soffit at the eaves main purpose is to ventilate your attic and roof system.

While the drip edge is typically recognized as the horizontal flashing at the end of the eaves, it should also be connected to and installed along the rake edges. When water hits the rake edges, it will run down the metal toward the drip edge installed at the eaves.

Types of drip edge

For the most part, there are three main types of drip edge. While each one accomplishes the same purpose (to direct water away from the house), they may be used in slightly different ways.

• Type c – Type C drip edge is L-shaped (bent at a 90-degree angle) with a lower flange. While it is not always the preferred type of drip edge flashing, it can work well with low-pitched roofs.
• Type d – Also called “hemmed edge,” or “T-shaped” drip edge flashing, Type D is bent specifically so that water runs out further away from the fascia. It’s great for directing water directly into the gutter or away from the foundation.
• Type f – Also called “gutter apron” flashing, Type F is also L-shaped (bent at a 90-degree angle). It drapes directly over the fascia and prevents water from running underneath the shingles.

Installation and materials

The top part of a drip edge is typically fastened directly into the roof, while the lower flange fits snugly against the fascia without a fastener. When installed at the eaves, drip edge/gutter apron should be nailed (every 12 inches) directly into the plywood decking. When installed at the rake edges of the roof, drip edge should be installed over the underlayment. In either case, the top half of the drip edge should always be fastened underneath the shingles if at all possible.

To ensure proper water runoff, roofers need to make sure the drip edges at the eaves and the rake edges of the roof are connected. Most of the time, they will cut and bend a piece of the metal to fit snugly around the corner of the roof so it creates a solid seal between the two pieces. This is common with other types of roof flashing as well. It’s important to make sure the metal pieces overlap by at least one inch to prevent leaks.

Whether you’re installing drip edge on a new roof or an existing roof, there are several materials you can choose from:

• Aluminum – Aluminum drip edge flashing is the most affordable material, and it’s sturdy enough to hold up for many years. It also doesn’t corrode, making it a solid choice for most homes.
• Galvanized steel – Steel is much stronger than aluminum, but it is also more expensive. It’s important that the metal be at least 24 gauge galvanized steel to hold up against strong winds and prevent rust.
• Copper – Homeowners typically choose copper drip edge flashing to provide curb appeal. While it may be the most expensive option, a 20-ounce copper drip edge is very sturdy and can sometimes last for 100 years.

Why a drip edge is essential for your roof

While many local building codes now require a drip edge for proper roof installation, some older homes may not have had it installed in the first place. For many years, the roofing industry used outdated techniques that didn’t always protect homes most effectively. Now, due to multiple decades of innovation, drip edge is required by most building codes for good reason. Without a drip edge, your home is especially vulnerable to multiple types of damage.

On the other hand, having a well-installed drip edge on your roof can protect your home from harsh weather and deterioration for many years. If your home does not have a drip edge or functional equivalent, it’s important to hire a trusted roofing company to install the drip edge properly.

Dangers of not having a drip edge

In the same way water runs down the edge of a glass, rain can also run over the surface of your shingles and back underneath them. Without a drip edge to block and redirect the water, rain will continuously run under your shingles and cover your plywood decking. Over time, this will rot the wood and may create mold issues, especially when there is no direct sunlight to dry it up after a storm. This will cause your roof to decay much faster than it should and often makes for a very expensive replacement project.

In the same way, a roof without a drip edge can allow water to run back against the fascia. Over time, this can deteriorate the support system of your roof and cause it to collapse. It may also cause water to leak into your walls and down into your foundation in such a way that you won’t notice the leak for a long time. Leaks like this can create mold issues in your walls, damage your electrical system, and erode the foundation of your home.

Benefits of having a drip edge

There are plenty of ways a drip edge can help protect your home from the elements:

• Sealed gaps in the roof edge – Over time, a gap can form between the roof edge and the fascia. As rain continues to run back against the house, it may cause this gap to become larger, allowing water to deteriorate the roof decking. This can also allow small animals like squirrels and mice to be able to crawl through the gap into your attic. Having drip edge flashing seals this gap.
• Protected fascia and house foundation – When water runs off your shingles, it may run backward and drain against the fascia. This will eventually deteriorate the wood, but a drip edge can redirect the water away from the fascia and into the gutters. Similarly, if water is allowed to run directly off the edge of your roof and against the walls of your home, it can leak down into your foundation. This can create serious problems that call for expensive repairs. With a drip edge, water can be directed away from the edge of the house and protect your foundation from water damage and erosion.
• Fortified roof edges – The edges of a roof tend to wear out faster than the other parts. Installing drip edge protects them from this deterioration by directing water away from the edge. Because it also fits tightly against the roof edge, it can hold the roof decking and fascia together and prevent damage from excessive movement.
• Protection against ice dams – Ice dams typically form on the roof’s edge, with icicles hanging from the fascia or soffit. But if a T-shaped (Type D) drip edge is installed to hang over the eaves or rake edges, icicles are more likely to form on that piece instead. Since metal drip edge is made of a stronger material than the wood fascia or roof decking, the ice likely won’t harm the roof’s integrity. Metal is more likely to withstand the weight of the ice.

When you don’t need a drip edge

While drip edge flashing is essential for most homes, some roof designs achieve the same function in other ways. For instance, if you have pre-bent aluminum fascia that is flush against your roof decking, you don’t need to install drip edge flashing, (according to most local building codes).

In other cases, you may have an older home with rake molding installed on the rake edges of your roof. Because many of these homes were built before industry standards were updated, many local building codes don’t require drip edge to be installed at the gable ends of these homes.

Final thoughts