Conforming to AS 3740

Summary only of the requirements to be compliant with AS 3740


As 3740 Included In BCA May 2004

Waterproofing of wet areas in residential buildings.


Requirements : House on Slab.


Flash all wall floor junctions in all wet areas : WC, LAUNDRY, POWDER ROOMS BATHROOMS,


Install water stop angle to wet area door openings.


Bathtops : waterproof all junctions, wall bath, external corners.


Preformed Shower base: Waterproof -wall to base, internal corners to 1.8m, seal tap penetrations, seal all mechanical penetrations and joins in wallboard. (full walls ). Waterproof Floor to base junction. (As in Wall floor junction).


Tiled shower base : waterproof entire base , insitu bases require water stop angle to be fitted at shower screen perimeter. Walls as above.


Timber floors : Full floor waterproofing is best practice, required in rooms with an insitu shower base or shower over a bath, Flexitray Specification for Retaining Walls and Balconies:-


Retaining Walls : MUST be bagged. Reasonable access is required. Brick wall – footing, junction must be clear of mortar buildup.


Balconies : Must be pinus ply or compressed sheet securely attached (ideally screwed and glued) to joists. Upstand under doorways in place. Consider building fall into structure to eliminate cement screeds. Drainage spitters must be installed prior to waterproofing. Click here to go to Balcony and Decks recommendations on our Points to Remember page.