A tiny perforation in your roofing material can lead to major water damage. Although your shingles may be in great shape, they flank many areas where water could seep in. The junctions where the roof meets the chimney, vents, walls or eaves should be protected with flashing. Valleys must also have adequate flashing because they are exposed to significant water flow.
There are various types of flashing. Some are specific to certain situations. An experienced roofer will incorporate the appropriate flashing during roof repairs and installations. Failure to install flashing properly is a leading cause of leaks.
Counter Flashing
Brick or masonry walls that rise above a roof’s surface require flashing to direct water away from the roof. It goes over sidewall flashing to prevent water from seeping in behind it. Counter flashing is commonly used around chimneys.
Although it is often applied with sealant on existing sidewalls and headwalls, counter flashing is most effective when it is installed in the mortar joints. Existing mortar joints can also be ground down to accept counter flashing. Then, they are sealed with soldering and masonry.
Step Flashing
Step flashing is used to direct water away from areas where the roof meets a vertical wall or chimney. You can find it around the following elements:
- Dormers
- Additions
- Where a one-story roof meets a two-story segment
- Skylights
A rectangular piece of metal is folded and placed in the junction, creating a sealed channel for water to flow. You can purchase pre-folded or unfolded step flashing. You may need to fold it manually in areas with atypical angles.
Aluminum and galvanized steel are usually used for step flashing because these materials resist corrosion and stand up to the elements.
Apron Flashing
Apron flashing, sometimes called headwall flashing, is placed along the upper edge of a roof that terminates at a vertical headwall. This L-shaped metal flashing comes in long lengths, creating a seamless transition in these vulnerable areas. Apron flashing is placed behind the siding or combined with counter flashing on masonry.
Gutter Apron Flashing
There is often a gap at the edge where the roof meets the gutter. Gutter apron flashing comes in long lengths and is bent to facilitate water flow into the gutter. It protects the fascia and other water-sensitive materials beneath the eaves.
Drip Edge Flashing
Drip edge flashing has a similar function as gutter apron flashing. However, it has a T-shaped cross-section instead of an L-shaped one. It also protects the fascia from rot and directs water into the gutters. Both types of gutter flashing are available in a variety of colors.
You may have to ask about drip edge flashing when you get a new roof. It is not usually included in standard roof installations. Drip edge and gutter apron flashing are also difficult to add to an existing roof.
Penetration Flashing
The vents on your roof create vulnerable transitions that must be protected with flashing. Some conduit penetration flashing is pre-molded to fit various vent widths. This type of flashing involves using a series of collars, sleeves and membranes to prevent water from entering around a vent.
Ridge/Hip Flashing
Installing flashing where the roof slopes meet at a ridge is essential for safeguarding the structure. Ridge and hip flashings are bent to match the pitch of your roof and may include architectural elements, such as rounded ridge caps, to provide a tidy, finished look. These flashings also come in various materials and colors, including copper.
Valley Flashing
Valley flashing is necessary for protecting channels that collect and direct water. There are several types of products and installation methods for adding valley flashing to a roof. A v-shaped valley meets at the bottom of a downward slope. A w-shaped valley is a length of flashing with a raised ridge in the center. The addition of the ridge prevents water from flowing under the shingles of the adjoining slope.
Open valleys are not hidden by shingles or roofing material. Therefore, the flashing material remains visible. Closed valleys are covered completely by the exterior roofing surface. Shingles may be cut to the angle of the roof or overlapped at the transition. The open style of valley flashing is more durable than closed valleys. However, it is a more complex and expensive installation process.
Cap Metal Flashing
Cap metal flashing is used to prevent water from getting into the top of a parapet. Placing a waterproof membrane beneath this type of flashing provides further protection and strengthens the parapet. Cap metal flashing is more prevalent on commercial roofs than residential ones.
Gravel Stops
This type of flashing has more than one function. It has a raised edge, which contains gravel and other debris on a concrete roof. It also has a drip edge, which diverts water into the drainage system. Gravel stops protect the fascia and give concrete roofs a finished appearance.
Door and Window Flashing
Doors and windows must have proper flashing to prevent water from entering the space around them. You can use a variety of flashings around doors and windows. Self-adhesive and drip-cap flashing are popular options.
Using Flashing Properly
Flashing protects the roof decking and skeleton, as well as the entire structure of your home, from water damage. However, it must be installed with plenty of overlap from the external material to create a water-tight seal.
Although the standard color for flashing is silver, it comes in other shades. Some contractors customize the color of the flashing to complement your home. An industrial coating adds strength and resilience to the material.
Flashing installation should be accompanied by the application of an ice and water shield. This provides additional waterproofing to vulnerable areas. But overuse of ice and water shields can impede the ventilation in your roofing system. That’s why it’s so important to work with an experienced contractor when installing or repairing flashing.
At Presidio Roof, we take pride in using quality materials and installation methods. Let us help you safeguard your roof so that you don’t have to worry about leaks and water damage.