Roof Valley and Drip Edges Installation

When installing a roof, it’s essential to consider the potential for water damage. One key area of concern is the roof valley, where two slopes of the roof meet. If water accumulates in this area, it can seep into the building and cause damage.

To help prevent this, you should install a drip edge along the roof valley. This is a piece of metal or vinyl that directs water away from the building and prevents it from pooling in the valley. You should also install drip edges along the edges of the roof. This way, you are directing water away from the building that helps keep the foundation dry.

Roof valley and drip edges installation is not a DIY project unless you’re trained and have specialized tools. As they say, leave it to the experts, like Irvine Roofing!

Roof Valley Installation

The first step of installing a roof valley is installing some metal expansion flashing at the point where the roofs intersect. We use masonry nails to drive them down firmly. They are also easy to remove later on in this process if necessary. The cut area should be repaired with roofing cement afterward. Slip another piece of metal flashing under the shingle and extend it out about 12 inches along either side of the valley, overlapping three times.

We keep putting more pieces in until we reach the edge where one tile ends and another begins that is almost 3 feet long or more depending on your needs, then puncture holes along under each nail with an awl before sealing everything with tar included in the roof valley kit.

Our Process


Set Up Inspection

Call us and we’ll be out to your home to offer a free inspection.


Review Your Home

We provide a thorough inspection so that you can be sure of the condition of your home.


Create A Plan Of Action

We’ll provide you with details about the condition of your roof and how we’d suggest resolving the problems.


Execute the Plan

Our team will ensure that your property is as clean or cleaner than how we found it.


What Are Roof Valley and Drip Edges?

A roof valley is a space created between two intersecting roof slopes. They are often found on taller buildings and are necessary to drain water properly. A drip edge is a thin metal or plastic strip installed along the eaves of a roof to prevent water from running down the side of the building. It helps to keep the roof deck dry and prolongs the life of the roofing material.

Drip edges provide an aesthetically clean look to a roof’s edge. They can be colored to match the roofing materials or left silver/white if desired. They also promote a dry building envelope by preventing water from running down behind shingles. It helps prevent black streaks from appearing on walls and siding — not to mention increasing protection for underlying building materials such as window flashing, fascia boards, gutters & downspouts.

A drip edge provides many benefits:

  • It prevents water from dripping down building walls and staining them with rust stains. This is especially helpful when the building’s exterior is brick, stone, or masonry. This will also reduce damage caused by moisture to the wall covering, such as paint and siding materials.
  • In addition to preventing water from running down onto a finished wall below, a drip edge also prevents moisture from creeping in behind the exterior covering and causing deterioration of the wall backing (studs, insulation, etc.).
  • It prevents snowmelt and ice damming at the eave of a building by directing water away from it. This is especially important when there may be an extended period of freezing temperatures followed by thaw periods. This is when ice dams are most likely to form and cause leaks in the roofing system above it (in addition to causing damage to the exterior wall of a building).

Dramatically reduces wind-driven rain coming under the eave into a building. As experts, we have personally watched it being blown completely off a roof around a corner and into a window on the side of the house.

Both a roof valley and a drip edge should be installed during a new roof installation. The drip edge is usually attached to the fascia board, while the valley flashing is installed in the valley between the two roofs slopes. We ensure that both components are properly sealed to prevent water from leaking into the building.

If you suspect roof damage, it is a good idea to call certified contractors to check the condition of the valley and drip edge. If either component is damaged, it needs to be replaced immediately to prevent water damage.


Valleys are unnecessary, but they are recommended for roofs with more than one slope. Without a valley, the water would flow over the edge of the roof and cause damage to the fascia, soffits, gutter, foundation, and/or interior of the home. Drip edges are excellent for any roofing project where shingles meet at either the ridge or overhang, preventing water from traveling behind the shingles and rotting away any roof components.

Many types of metal flashing are available, but most roofers use either aluminum or galvanized steel flashing. Aluminum flashing is lighter and easier to work with, but it is less durable than galvanized steel flashing. On the other hand, galvanized steel flashing is more expensive, and it is stronger and less likely to corrode.

The cost of a roof valley and drip edges installation will vary depending on the size of the project and the materials used. However, typically, homeowners can expect to pay between $500 and $1,000 for this type of project. Other factors that affect the cost are design specifics.

Principles in Roof Valley and Drip Edges Installation

Builders have many different ways to handle roof valleys and drip edges. Much of it is a matter of personal preference. Some are governed by local custom – but there are even more reasons why the installation of these components varies among individuals and regions.

In California, to successfully get a weatherproof seal at a roof valley or along the edge of a building’s eaves, a few basic principles must be followed:

  • The most important of these is that the upper edge of any valley flashing must never be covered with any material – not shingles or building paper. The upper-most portion of a roof valley receives the greatest exposure to the sun’s ultraviolet rays and seasonal temperature fluctuations. These elements can cause the protective coating on the upper surface of your shingles to deteriorate, making that material very fragile. Covering it with shingles will only speed deterioration and render the valley flashing ineffective.
  • Another reason why metal valley material is preferred over shingles is because of its resiliency in extremely hot weather. Metal, especially aluminum, doesn’t tend to warp the way shingles can, so it forms a more watertight seal. To ensure that your roof valley is appropriately sealed and protected against the weather, we use a metal valley flashing. This also ensures that it extends beyond the roofing material by at least two inches on each side.

The same principles apply when installing drip edges. The most crucial factor is ensuring that the drip edge extends beyond the roofing material by at least one inch on each side. This prevents water seeps underneath the shingles and causing damage to the roof deck.

Drip Edge Installation

The drip edge should be placed along the roof’s eaves, extending out about 1/2 inch. It is important to ensure that the drip edge is appropriately aligned and that there are no gaps between it and the roofing material. Nails or staples can be used to attach the drip edge to the roofing material. Be sure to seal all seams with silicone caulk or roofing cement.

As homeowners, it’s always best that both the roof valley and drip edges are well-maintained to prevent water damage to your home. Make sure that any debris or leaves are cleared away from them. It is also a good idea to inspect the roof valley and drip edge after every rainstorm, particularly if you have them installed recently. Remove any nails or other pieces that may become loose, and apply more tar if necessary.