For brickwork on a concrete slab.
Flashing is put in on top of the first course above the concrete slab rebate, weep holes are put in no more than every 4 perpend joints apart, 1200mm maximum.
Weep holes are just perpend joints clear of any mortar.
Maximum distance between weep holes, 1200mm
It is always better to put the weep holes closer than the maximun allowed.
For brickwork on a footing.
Cavity flashing isnt required on the first course when building on a footing, 100mm wide damp course is used instead (the 100mm damp course does the same job as the cavity flashing in keeping out any rising damp),
The air flow from under the floor will keep the cavity moisture free and the 100mm damp course allows any water that enters the cavity to fall to the ground.
Above openings.
Flashing is put in on top of the first or second course above any openings (windows, doors, etc.) and run at least 100mm past the window or door opening so that any water can drip into the cavity rather than onto a window or door.
Cavity Flashing
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Brickwork.net.au
Contrary to popular belief, cavities are supposed to be free of pipes and wiring.
The whole idea of the cavity is to provide an air barrier between the outside and the inside of the building.
If the cavity is full of pipes etc, then mortar may fall on top of the pipe and breach the cavity allowing moisture to travel to the inside of the building.
Basic lay out of cavity flashing as used on current brick veneer construction.
The same method would apply to a two skin brick construction (solid brick) with a cavity.