Flashing Installation for Wood Roofs

The installation of flashing on wood roofs may not be difficult at all and can be a DIY job with the right skills and tools. It is not common for most people to have the tools or knowledge to perform such a task, so a local contractor is usually called to do the job. It is still important to have some important information about this process.

Copper Flashing

Copper is a popular material for use as flashing on wood roofs; however, some experts suggest that it should not be used with red cedar. If it comes in direct contact with the roof, it could cause soluble tannins to etch the copper, which could lead to perforations within ten or twenty years and a shortened lifespan.

Premature failure of such roofs has been documented in some areas of the United States, especially that east of the Great Lakes sometimes exposed to acid rain. To resolve this issue, the Copper Development Association recommends adding a cant or hemming on the flashing joints to hold the edge of the cedar slightly away from the copper to prevent acidic water from etching into the copper and causing damage.

Valley Specifications

Open valley designs are typically used with most wood roofs. Though the requirements from the International Residential Code (IRC) for valley flashing is to have a minimum of 11 inches of extension up each side for shakes and at least 10 inches for shingles, many contractors may decide to use wider valleys of 24 to 36 inches, based on the area and pitch being drained. An extra layer of 36 inches wide No. 30 felt will protect the valley flashing when it is installed directly under the metal. Additionally, applying a layer of self-adhesive bituminous membrane directly to the sheathing will add protection. Make sure to set aside the widest shakes or shingles for valley use and the valley centerline in order to have at least 12 inches for nailing.

Skylights and Chimneys

Skylights and chimneys should be conventionally installed using step flashing on the sides. For shakes, use 4 inches for the horizontal legs and 3 inches for the vertical legs. For shingles, use 2-1/15 inches for both the horizontal legs and vertical legs. A soldered apron can be used below the chimney and a soldered head on top. A chimney cricket can be utilized for larger chimneys that may experience a significant water flow.


Safety should be a priority, using a safety harness/is vital when walking around the surface of the roof to prevent falling and serious injury. Before climbing onto the roof, be sure to check and double-check that the harness is secure, tight, and properly adjusted.

It is also important to ensure that the surface is safe for walking. Do not attempt to climb on a roof if the surface is wet or there are leaves strewn about as this could cause a slip and fall accident. If it is absolutely necessary to climb onto the roof, clean it off using a broom. The best thing to do is to call a roofing professional if there is any uncertainty about the strength of the roof.


Learning about some of this important information about flashing installation will provide an idea on about the best material to use and how it should be properly installed. If unsure about performing the installation properly, contact a local professional to expertly handle this job of flashing installation for wood roofs!

Contact Schulte Roofing – Your Local Brenham Roofer!

Have you been searching for a Brenham Roofer to install proper flashing on your wood roof? The experts at Schulte Roofing at 800-367-7663 can help you and other Brenham area customers with any roofing needs!