A balcony or deck that leaks onto the space below is one of the most common — and most damaging — building faults. Goliath Coatings delivers deck waterproofing across Auckland with flexible, durable membrane systems for balconies, decks and podiums that stay watertight under foot traffic and weather.
Why deck waterproofing fails — and how we prevent it
Most balcony leaks start at the details: the upstand under the door, the junction with the wall, the drainage outlet and the balustrade fixings. Good deck waterproofing treats these first, with reinforced detailing at every upstand and penetration, before the field of the deck is coated. We also check the falls — water must run to the outlet, not pond — and correct them where needed.
The systems we install
We apply liquid-applied membranes that cure to a seamless, flexible, trafficable surface, finished with a UV-stable, anti-slip topcoat in a range of colours. For tiled balconies we can waterproof beneath the tile or apply an exposed membrane as a finished walking surface, matching the system to how the deck is used and how it looks from inside.
New decks and leak remediation
We waterproof new balconies and decks and remediate existing ones that have begun to leak. For remediation we find the true entry point rather than just recoating the obvious area, so the fix actually stops the water reaching the rooms below.
The products and systems we use
Balconies and decks leak when the membrane is wrong for the finish above it. For exposed foot-traffic decks we use Ardex Butynol, NZ’s locally-made butyl rubber membrane, and heat-welded Viking Dec-K-ing vinyl. Under tiles we use liquid membranes such as Ardex WPM 155 Rapid and Mapei Mapelastic AquaDefense, or Sika Sikalastic under trafficable finishes. Each is detailed at upstands, drains and door thresholds where balconies typically fail.
Why choose Goliath Coatings
Balcony, deck and podium waterproofing are a specialty. We own our prep and application equipment, specify premium systems matched to the job, and back every project with genuine 5-star Auckland reviews. You get a free on-site assessment and a one-business-day response.
Deck waterproofing FAQs
Q: My balcony leaks into the room below — can you fix it?
A: Yes — we trace the leak to its real source, usually an upstand, outlet or junction, and remediate the detail rather than just recoating the field.
Q: Can you waterproof a tiled deck?
A: Yes — we can waterproof beneath new tiling or apply an exposed trafficable membrane as the finished surface, depending on the look you want.
Q: Is the finished deck slip-resistant?
A: Yes — we finish exposed membranes with a UV-stable, anti-slip topcoat so the deck is safe underfoot when wet.
Q: Should my balcony membrane go under or over the tiles?
A: Either, but the product differs — exposed decks use Butynol or Dec-K-ing, tiled balconies use an under-tile liquid membrane like Ardex WPM 155 or Mapelastic AquaDefense. We match it to the finish and the detailing.
