Stop water getting into your concrete, not just onto it
Concrete looks solid, but in Auckland's wet climate it is one of the most common paths for hidden water damage. We assess the structure first, then install the waterproofing system that actually suits it.
What water does to unprotected concrete
Concrete is porous. Without a proper waterproofing system, water moves through it, and the damage does not stay on the surface:
- Damp patches and efflorescence, the white salt stains that show water is actively migrating through the slab or wall
- Cracking and surface deterioration
- Rusting steel reinforcement inside the concrete
- Long-term structural weakening
By the time you can see the problem, it has usually been running for a while. That is why the areas we treat most are the high-risk ones: basement walls and floors, slabs and foundations, podium decks, pool surrounds, and the concrete substrates under bathroom and wet-area tiling.
The right system for the right structure
Most concrete waterproofing fails for a simple reason: wrong system, wrong application, no diagnosis. Coatings go onto damp or unprepared concrete, movement and cracking get no allowance, and joints and penetrations are poorly detailed. Water does not need a big opening, just a weakness.
We assess first, then apply one of two proven approaches using Ardex, Sika and Mapei systems:
- Surface membrane systems - a flexible barrier over the concrete, ideal under tiles and on exposed areas, built to handle movement
- Penetrative crystalline systems - these react inside the concrete and block water within the pores, suited to basements and below-ground structures
Preparation is most of the job: clean, sound, correctly primed concrete, with joints and penetrations detailed properly before any product goes on.
When concrete has already failed
If water is already coming through, patching the surface will not fix it, the coating just fails again from behind. Failed concrete waterproofing is a rebuild job: identify where the water is entering, strip the affected finishes back to sound substrate, and reinstate the full system: membrane, detailing and finishes together.
We take that work on as part of renovation-scale projects, for example stripping and rebuilding a leaking tiled area over a concrete substrate from the slab up. We do it once, properly, with a PS3 producer statement where the work is consented.
Before you book
My basement wall is damp with white powder on it. What is that?
That is efflorescence, salts carried to the surface by water moving through the concrete. It is a reliable early warning that water is actively migrating through the wall, usually driven by hydrostatic pressure from groundwater. Painting over it changes nothing; the moisture path has to be addressed at the source.
Is it better to waterproof concrete from the inside or the outside?
For below-ground concrete, the outside is almost always better, a membrane on the external face stops water before it enters the structure. Internal coatings work against the water pressure and tend to fail over time. Where excavation is not feasible, crystalline systems that work within the concrete are the sound internal option.
Does concrete waterproofing need building consent in Auckland?
Often, yes. External and below-ground waterproofing falls under Building Code clause E2, internal wet areas under clause E3, and consented work needs a PS3 producer statement before council sign-off. If you are unsure, we can tell you at the site visit what your project will trigger.
How long does concrete waterproofing last?
A professionally installed system should give decades of service, with below-ground tanking generally outlasting exposed surfaces. Watch for damp patches, efflorescence, musty smells or water appearing after heavy rain, those are signs the system needs attention before minor seepage becomes structural damage.
Get the concrete assessed before it gets worse
Free site visit, straight answers about what your structure needs, then a clear, itemised quote. Call 021 818 013.