Brick veneer flashings
A flashing is an impervious material designed to prevent water from entering the brick cavity from joints such as those found in windows and doors.
The brick veneer system has functioned in New Zealand very successfully for many years with minimal flashings being installed; however, in the modern environment, flashings are an essential part of any cladding systems.
Designers and bricklayers should families themselves with Figure 73 Cof E2/AS1 which can be viewed here: E2/AS1(part4)
It is the bricklayer’s responsibility to ensure that all flashings have been correctly installed prior to the bricks being laid.
If a metal head flashing is used and fixed to the framing, you should ensure it is kept 5mm short at each end and the ends of the flashing should be turned up.This will allow for any movement in the framing without interfering with the bricks.
A 5-10mm gap between the underside of the lintel bar and the flashing allows for both drainage and ventilation eliminating the need for weep holes in the bricks across the head of the opening.
Jamb flashings are simple and inexpensive. Use a 200mm wide polyethylene flashing, tucked into the joinery flange. The open end of the flashing is to be held off the building wrap using a kick-out batten or protruding clouts. The junction between the bricks and the joinery does not need to be sealed.
Any moisture being driven up the sill brick needs to be stopped from reaching the timber framing and redirected into the bottom of the cavity. NZS 3604 S11.7.7 requires that flashings be extended
200mm past the sides of any openings where practical to do so.
You can read the next section here:
Designing and Constructing Brick Sills and Lintel Bars