Tempo:
of the same material as the main roofing membrane or of a compatible material (see Figures 117 and 118). 117 Base flashing at roof penetration
surface to avoid a right-angle bend, which might rupture the roofing membrane (Figure 118). Membrane roofing is more flexible than built-up roofing, and usually does not require a cant strip. The roofing membrane should extend at least 150 mm (6 in.) up the wall and over the sheathing. Lap the sheathing paper at least 100 mm (4 in.) over the membrane.
Counter Flashing counter flashing base flashing
To prevent water from penetrating behind the top edge of base flashing, a separate piece of flashing should be provided over the top. This flashing is known as “counter flashing” and is usually made of sheet metal (see Figure 119). 119 Counter flashing
118 Base flashing at roof-wall junction sheathing paper
counter flashing base flashing cant
saw cut
counter flashing base flashing cant roof
roof
Where siding is used as cladding material, the base flashing is turned up behind the siding. Where siding abuts a roof, a space of at least 50 mm (2 in.) must be maintained between the siding and the roof surface. A cant strip should be installed where a built-up roof abuts a vertical
Counter flashing is also required to protect the base flashing from impact and UV radiation damage. This is necessary if the base flashing is a built-up bituminous roofing membrane or made of any material that deteriorates in sunlight. Counter flashings should be installed so that they are easily removed to allow for inspection of the flexible base flashing below.
surface to avoid a right-angle bend, which might rupture the roofing membrane (Figure 118). Membrane roofing is more flexible than built-up roofing, and usually does not require a cant strip. The roofing membrane should extend at least 150 mm (6 in.) up the wall and over the sheathing. Lap the sheathing paper at least 100 mm (4 in.) over the membrane.
Counter Flashing counter flashing base flashing
To prevent water from penetrating behind the top edge of base flashing, a separate piece of flashing should be provided over the top. This flashing is known as “counter flashing” and is usually made of sheet metal (see Figure 119). 119 Counter flashing
118 Base flashing at roof-wall junction sheathing paper
counter flashing base flashing cant
saw cut
counter flashing base flashing cant roof
roof
Where siding is used as cladding material, the base flashing is turned up behind the siding. Where siding abuts a roof, a space of at least 50 mm (2 in.) must be maintained between the siding and the roof surface. A cant strip should be installed where a built-up roof abuts a vertical
Counter flashing is also required to protect the base flashing from impact and UV radiation damage. This is necessary if the base flashing is a built-up bituminous roofing membrane or made of any material that deteriorates in sunlight. Counter flashings should be installed so that they are easily removed to allow for inspection of the flexible base flashing below.
©
2026
Lehal.net