Remedial, strata and commercial waterproofing in Sydney

Remedial work starts from something that has already failed, often more than once. The first job is finding where water gets in, which is rarely where it shows: it can run along a slab, a tile bed or a wall cavity before it appears in the unit below.

A leak that keeps coming back usually means an earlier repair treated the symptom. Silicone over a crack, a clear sealer on the tiles or a coating on the ceiling below can stop drips for a season while the membrane underneath stays broken.

The options run from a local repair at one detail, through a new membrane over sound existing tiles, to stripping back to the slab. Which one is right depends on the substrate, the tiles and how many times the area has been patched already.

On a strata building the leak and the damage are usually in different lots, and the balcony, roof or planter it comes from is often common property. Access, notice to residents and entry to the units below are arranged through the strata or building manager, and the work stays within the scope the owners corporation has approved.

In an apartment building (Class 2 under the building code), remedial waterproofing is generally regulated building work under the Design and Building Practitioners Act 2020. A registered design practitioner prepares the design, and the regulated design and design compliance declaration are lodged on the NSW Planning Portal before work starts, so allow for that step in the timeline. The exception for waterproofing covers only bathroom, kitchen, laundry or toilet alterations in a single dwelling that are also exempt development.

Commercial remedial work follows the same steps as a strata job: find where the water gets in, agree a written scope with the owner, agent or facility manager, then repair it. That covers flat roofs, balconies and terraces, staff bathrooms and other wet areas, basements and lift pits, with noisy or dusty stages planned around trading hours and tenants.

A building with apartments in it, including shops with units above, is Class 2 work, so the design step above applies. A building with no residential part usually isn’t, and the scope comes from the owner or their consultant; the work follows it and the site’s induction and safety rules.

Over-tile systems suit balconies, terraces and some flat roofs where the tiles are firmly bonded, the water drains properly, and the leak is through the grout and joints. They avoid the noise, dust and time of demolition, which matters most in an occupied building.

They don’t suit floors with drummy tiles, ponding or a broken-down bed, and they raise the surface slightly, so door sill and outlet heights are checked before this option is offered.

Usually, for over-tile repairs and roofs. Stripping tiles back to the slab is noisy and dusty, and the area can’t be used until the new membrane and finish have cured, so residents of the lot need notice.

Yes: shops, offices and mixed-use buildings, on roofs, balconies, wet areas, basements and lift pits. Send photos, the suburb, and any access or trading-hour limits.

On an apartment building, remedial waterproofing that is regulated work needs a design from a registered design practitioner before it starts. Your strata manager can confirm whether a particular repair is regulated.

Photos of the damage from below and of the balcony, roof or planter above it, the building’s age if you know it, and any earlier reports or quotes. Strata managers can include the building and lot details so access can be planned.