Flat Roof Against Wall

Step 3 flashing angled roofs with the step method you can use the step method to flash an angled roof.

Flat roof against wall.

Sheet of housewrap or even better a piece of self adhering roof underlayment to the wall before the first truss or roof rafter is placed against it. If the roof runs flat up against the brick wall you must install the roof side of the flashing either under the last layer of shingles or over the roof material if it is metal. The flat roofing material must go up the wall a minimum of 12 or up the wall and over the top of the wall if the wall is less than 12 high. When building a single story flat roof addition on a two story house the flat roof will normally simply butt up against the side of the wall.

If the membrane is asphalt built up or modified bitumen a cant strip is typically used. Flat roof and flashing against brick wall install base flashing under shingles or over metal roofing material. Housewrap creates the foundation. It is common for flat roofs to terminate against walls that are higher than the roof.

Ideally i like to start by installing a 3 ft. This makes it very simple however it does create a weakness in the design. Here is an attempt though maybe not a very good one to make the roof flashing serve also as a through the wall flashing with a tile roof. For example a one story garage with a flat roof may be attached to a two story house.

The sheet acts as a backup at a vulnerable junction. You have to install the roof side of the flashing either under the last layer of shingles or over the roof materials if the roof runs flat up against a brick wall. Flashing must be applied along the gap between the flat roof and the brick wall to ensure that everything is watertight and secure. Proper roof wall abutment flashing examples.

In the case of the perpendicular gable the roof rafters are parallel to the wall the rafters that form the wall side gable are flush against the wall and the ridge board at the peak of the roof. Follow the photo for illustrated instructions.