Page 44 - Build 161

K A
n
v p
W
cavity batten
depth as required for cladding
TATN
A full tanki A full
as a positi as a
exible ashing tape to ashing upstand
cavity closure
50 mm minimum upstand
continuous air seal over backing rod
wall underlay turned into window opening with exible ashing tape to corners
65 mm
in ll panel (sheet or weatherboard
5 mm drainage gap Protecto Wall® Protecto
timber reveal
aluminium window
rigid corner ashing (shown dotted) behind cavity batten lapped 65 mm minimum by in ll cladding and butted to face of bricks and aligned with window
head ashing with 15° slope and stop- ended to edge of bricks
masonry veneer
Door sill openings
Door sill openings must have:
● a sill tray flashing that is the full width of
the opening and has a depth that extends past the back of the aluminium joinery profile
Figure 6
Aluminium window installation – head detail with in ll panel.
and timber window frames. Note that E2/AS1 does not require a rigid head ashing for alu- minium windows.
For very high (VH) and extra high (EH) wind zones, sealant must be applied between the underside of the head ashing and the top edge of the window head ange (see Figure 2).
Infill panel above opening
Where a window is installed with an infill panel instead of bricks above the opening, rigid corner flashings for the full height of the panel must be installed behind the cavity battens. They must be lapped at least 65 mm by the panel and butted to the face of the bricks (see Figure 6).
Head and sill flashings
Head and sill flashings to masonry veneer openings must be either:
● 1.5 mm butyl rubber
● 2-ply asphaltic pliable waterproofing
membrane
● 0.5 mm minimum pliable polyethylene. Jamb flashings
Jamb flashings must be either:
● 2-ply asphaltic pliable waterproofing
membrane
● 0.5 mm minimum pliable polyethylene.
The ashings must direct any water that gets past the external cladding to the back face of the masonry veneer.
Window anges
Window flanges must be forward of the back face of the veneer by 10 mm minimum.
Continuous flexible air seals must be installed over a PEF backing rod between the reveals and window and door openings. Meter box
Openings for meter boxes less than 500 mm wide do not require a lintel or head flashing. However, the meter box must be sealed to the wall underlay and separated from direct con- tact with the masonry veneer or mortar with flexible flashing tape.
Sill requirements
Sill bricks or tiles should have a 15° minimum slope to the outside and an overhang to provide protection for ventilation slots if required below the window.
A gap of at least 20 mm should be left between the back of the sill bricks and the wall underlay and framing. This gap is to prevent mortar getting trapped and/or water bridging the gap.
● an 8 mm minimum upstand and sloped end
dams
● a 5 mm minimum air gap behind the
downturn.
Window sill openings
Specific requirements for window sill openings include:
● aluminium window sills must have a sill
support bar where the window is wider than
600 mm (see Figure 4)
● the flexible sill flashing must have a drip
edge created using a 20 mm H3.2 timber
kick-out fillet
● window sill flanges must not be sealed at
the sill edge.
BRANZ also recommends installing a rigid sill tray ashing for timber windows. The sill tray should be the full width of the opening, have stop-ends at each end and be sloped to suit the timber sill (see Figure 5). Note that aluminium windows do not require a sill tray.
Pro-Drain 8 Pro-Drain
42 — August/September 2017 — Build 161