Flashing Roof Against Vertical Wall

Obviously the further up the wall a flashing extends the greater the resistance to water intrusion.

Flashing roof against vertical wall.

At roof to wall intersections see figure 1. The through the wall z bar flashing is sized to the thickness of the vertical blocking backing lumber. A vertical cut about 2 in. A 5 inch wide flashing will result in a 2 1 2 roof deck flange and 2 1 2 vertical wall flange.

The flashing extends up the wall at least 4. Flashing is installed to surround roof features such as vents chimneys and skylights. Metal flashing also called roof flashing goes against a stucco wall to protect it from water damage. I then add a second piece of flexible flashing tape to cover the open corner of the metal flashing and i fold it down onto the subfascia.

Apply the shingles up the roof until a course must be trimmed to fit at the base of the vertical wall. A roof or wall that is not properly sealed off from water can be extremely costly to fix not to mention the hassles that accompany the unwanted water. Most simply use a nominal 6 piece of lumber. Tape the top of step flashing with 4 inch wide minimum self adhering modified bitumen roof tape.

The roof flashing is then placed up behind this through the wall z bar flashing on the outside of the vertical blocking backing material. Likewise a 10 wide flashing will result in a 5 inch wide roof deck flange and a 5 inch vertical flange. Flashing against vertical front walls to apply base flashing against a vertical front wall. For areas where the walls meet the roof you will need to use the step flashing technique but you will need kickout flashing in other areas.

The horizontal part of the flashing will vary depending on the type of roof covering material. Use flashing cement at joints to help secure flashing. It is extended down the face of the vertical blocking backing lumber and over the l metal at head walls and the step flashing at rake walls a minimum of 3. Flashing joints are lapped 6 in the direction of water flow.

The flashing extends onto the roof a minimum of 2 inches 4 inches is preferable in more severe climate areas. By planning ahead you can adjust the exposure slightly and evenly in the previous courses so that the last shingle is at least 8 vertically wide. I fold a piece of metal flashing for the inside corner between the subfascia and the wall. Except where walls are brick the vertical part of the sidewall flashing should extend up behind the exterior wall covering just like with headwalls.

Long helps it to fold onto the roof sheathing. Because most roof flashing is required to extend up the wall a minimum of 4 and some a minimum of 5. Use step flashing that has a 2 to 4 inch longer vertical leg than normal.