BCAB #1636 - Window Sill Flashing, Sentence 9.27.3.8. (5)

July 18, 2007

BCAB #1636

Re: Window Sill Flashing, Sentence 9.27.3.8. (5)

Project Description

The subject is the installation of a flange type vinyl frame window. Around the exterior perimeter of the window is wood trim about 18 mm thick. At the base of the window is a sloping (12 degree) sill trim which extends about 75 mm beyond the cladding. Flashing has been provided between the base of the window and the wood framing below and extends downward below the exterior window trim on the exterior sheathing.

Reason for Appeal

Sentence 9.27.3.8.(5) indicates where the sill of a window is not self-flashing, flashing shall be installed beneath the underside of the window and the wall construction below.

Appellant’s Position

The appellant considers the installation complies with the flashing requirements of Sentence 9.27.3.8.(5).

Building Official's Position
The Building Official does not consider the window to be self flashing and therefore the requirements of 9.27.3.8.(5) are applicable. This would include additional flashing behind the base window trim and trim sill, commencing at the top of the sill trim and carrying around between the base trim the cladding.

Appeal Board Decision #1636

It is the determination of the Board that the additional flashing behind the base window trim and over the trim sill is not a requirement of the Building Code.

George Humphrey, Chair