Fig A shows a flashing system at the junction of a sloping roof and a dormer. Apron flashing is in stalled as shown in Detail 1 or Detail 2. Counter flashing in Detail 2 may be sheet metal, plastic, or a combination of metal with paper, fabric or rub ber.

Pieces of base flashing are installed as each course of shingles is applied. The upper edge of each piece of flashing should extend 2 in. above each course of shingles. The lower edge should be 1/2 in. above the butts of the shingles forming the next course. The flashing must extend up the wall and onto the roof a minimum of 4 in. Flashing pieces are nailed to the sheathing above the top of each shingle course. Roofing felt and shingles on the wall serve as counter flashing.

Detail 3 shows a type of base flashing that must be attached to the roof before the shingles are in stalled.

The roof portion of this runner flashing is formed ~ with a hook edge and is cleated on 12 in. centers.

The flashing extends up the wall and onto the roof a minimum of 4 in. Joints in the flashing should be lapped 6 in. in the direction of flow. Roofing felt and shingles on the wall serve as counter flashing.

Fig B illustrates a method of flashing a door or window head. Flashing extends up the wall a minimum of 4 in. and is nailed to sheathing. Sheet metal is recommended for this flashing.

Figs C and D show flashings for window and door sills. Flashing is installed before sills are set in place. This flashing may be sheet metal, plas tic, or combination of metal with paper, fabric or rubber.