Below ground, no second chances
Basement waterproofing Sydney
Once a basement is backfilled, the membrane is buried with it. There's one chance to get it right, so we treat below-ground work as the most unforgiving job in the trade.
Below-ground waterproofing done once, done right
Above ground, a membrane failure is a stain on a ceiling. Below ground, it's a wet wall you can't reach without an excavator. Basement waterproofing, or tanking, is the one part of the trade where the repair can cost more than the original build, which is why the install has to be perfect the first time.
We tank basements, retaining walls, lift pits and below-ground rooms with torch-applied bitumen membrane systems: thick, seamless, fully bonded, and protected before backfill so the membrane survives the one event it can't be inspected after.
What we tank
- New-build basements and below-ground slabs
- Retaining walls and planter walls against living spaces
- Lift pits and service pits
- Below-ground garages, cellars and storage rooms
- Existing damp basements, assessed honestly for what's achievable from the accessible side
The detail that matters underground
Hydrostatic pressure finds everything: an unsealed penetration, a membrane turned down short, a protection board skipped to save a day. Our below-ground systems run membrane continuous through wall-to-slab junctions, seal every penetration with hand-cut detailing, and go behind protection board and drainage cell so backfill can't touch the work. Then it's documented in photos, because nobody will ever see it again.
Straight advice on existing basements
Not every damp basement can be perfectly tanked from inside, and anyone who says otherwise is quoting hope. If your basement can be fixed from the accessible side we'll design the system and stand behind it. If the honest answer is drainage management rather than full tanking, you'll get that answer for free instead of a $30,000 experiment.
- Torch-applied tanking for basements and retaining walls
- Continuous membrane through wall-to-slab junctions
- Every penetration hand-detailed and documented
- Protection board and drainage cell before backfill
- Honest assessment of what's achievable on existing basements
No fluff. No buzzwords.
Straight answers
What is tanking?
Tanking is waterproofing a below-ground structure so it holds out groundwater under pressure, effectively turning the basement into a sealed tank. We tank with torch-applied bitumen membranes, fully bonded to the structure and protected before backfill.
Can you waterproof an existing basement from the inside?
Sometimes, and it depends on the structure, the water table and where the water is coming from. Interior systems manage water rather than stop it at the outside face, so results have limits. We'll inspect, tell you what's genuinely achievable, and won't sell you a system that can't work.
When should basement waterproofing happen in a new build?
Before backfill, with no exceptions. It's a one-visit window: once soil goes against the wall, the membrane is unreachable forever. If you're building, get us in at the structural stage and we'll coordinate with your builder's programme.
Also worth a look
Related services
Can't afford for it to leak twice?
Call the blokes whose names are on the patch. Straight answers, a fixed quote and a warranty that means something.
