Exterior Waterproofing near you

H2D8 splits the requirement in two, and both halves matter. The membrane itself must comply with AS 4654.1, which is the materials half. The design and installation of the whole external waterproofing system must be in accordance with AS 4654.2, which is the design and installation half. A product that complies with the first, installed in a way that does not satisfy the second, gives you a compliant membrane inside a non-compliant system, and that is the single commonest way these jobs go wrong.

The distinction from internal wet areas is worth holding onto, because contractors and homeowners mix them up constantly. Internal wet areas are dealt with by Part 10.2 of the Housing Provisions and by AS 3740, and the numbers people quote about shower wall heights come from there. An external balcony is not a big shower: it is exposed to sun, rain, thermal movement and foot traffic, it drains differently, and it is governed by the AS 4654 pair.

The overarching duty sits above both. Performance requirement H2P2 requires a roof and external wall, including openings around windows and doors, to prevent the penetration of water that could cause unhealthy or dangerous conditions, loss of amenity for occupants, or undue dampness or deterioration of building elements. A balcony membrane that has failed is failing that requirement whether or not anyone has noticed the ceiling below.

The order is substrate, falls, membrane, protection, finish, and each step is harder to fix once the next one is on. The substrate is prepared and any cracks addressed. The falls are formed so that every part of the surface drains to an outlet, and this is checked with water, not with an eye. Only then does the membrane go down, taken up at every upturn and dressed into every outlet.

The details are where compliance with AS 4654.2 lives: upturn heights, terminations at doors and walls, treatment at outlets, and how the membrane is protected before the tiles or pavers go over it. Ask to see the membrane before it is covered, and ask for photographs of the upturns, the terminations and the outlets. Once the tiling is on, nobody can tell you what is underneath it.

Balustrades are the item to settle in writing before work starts. If the balustrade is fixed through the deck after the membrane is down, the membrane has holes in it, and no amount of sealant around the base plate is a substitute. Ask how the balustrade is fixed and in what sequence, because it is the question that separates a job that lasts from one that fails in the second or third wet season.

Waterproofing is a defined class of work in several Australian states, and the drainage side of it is licensed plumbing almost everywhere. In Queensland a QBCC licence is required for building work above the state threshold and for plumbing and drainage work regardless of value, and building inspection, termite management, fire protection and design services are in the same must-be-licensed group. Ask which class covers the work being proposed and check the number on the regulator's public register.

New South Wales reaches this work through the contract as much as the licence. Above the contract threshold the job must be under a written contract, and that contract has to include a quality of construction clause referencing the Building Code of Australia and the relevant standards. On a membrane job that clause is the hook worth using: it is what turns AS 4654.1 and AS 4654.2 from a technical expectation into a contractual term you can hold someone to.

Approvals depend on what is changing. Renewing a membrane on an existing balcony is often maintenance; altering the structure, changing levels at a threshold, enclosing a balcony or adding a new one is not. Your council or a registered building surveyor answers that for your address. In an apartment, the balcony is very often common property, which makes it a matter for the owners corporation rather than for you alone.

External waterproofing fails invisibly and slowly, which means the argument happens years after the work. Building Commission NSW publishes its Building Defects Library as a list of the most common defects found in its building site audits, organised into waterproofing, fire safety, structure, building enclosure and services. Being in the first category on that list tells you how often this work is disputed.

The evidence that settles those disputes is the pre-cover record: photographs of the prepared substrate, the falls, the membrane, the upturns, the terminations and the outlets, plus the product data sheets and the installation instructions for the specific membrane used. Ask for all of it at handover, not when the ceiling below stains.

The consumer guarantees the ACCC enforces sit underneath whatever the contract says: the service must be carried out with an acceptable level of care and skill, it must be fit for any purpose you made known, and where no timeframe was agreed it must be supplied within a reasonable time. Stating in writing that the purpose is to keep the room below the balcony dry makes that purpose part of the guarantee rather than an assumption.