Rooftop & Terrace Waterproofing
Roof decks, terraces and podiums. Ponding, failed junctions and blocked drainage put right, to AS 4654.
Water sitting still is water getting in
Flat roofs, terraces and podium decks fail at their edges far more often than in the middle. Upstands, parapet junctions, drain outlets and every penetration for a service or a plant unit are where the detailing has to be right - and where it usually is not.
Ponding makes all of it worse. Standing water loads the structure, accelerates membrane breakdown, and turns an intermittent defect into a permanent one, because there is always water sitting on it waiting to find the way through.
Ponding is a falls and drainage problem, not a membrane problem, so re-coating over it buys a season. We correct what is causing the water to sit before anything goes over the top.
How the work runs
Not every job needs every step. What it does need is established before you are asked to approve anything.
Establish where it is entering
Thermal imaging, moisture mapping and flood testing, because on a large deck the stain below is rarely under the defect.
Assess the falls and the drainage
Where water is ponding, the cause is the fall or the outlet. That gets identified before any membrane is specified.
Repair the substrate
Concrete repair, spalling and screed corrected, so the deck drains and the membrane has something sound to bond to.
Detail the edges
Upstands, parapet junctions, outlets and service penetrations detailed to AS 4654 - the parts that actually fail.
Waterproof the deck
The system the deck and its traffic call for, whether that is trafficable, planted or plant-loaded.
Test, reinstate and hand over
Flood-tested where practical, finishes reinstated, photographed, and handed over with the documentation and warranty.
Frequently asked questions
Because most roof and terrace failures are not holes in the middle of the membrane - they are at the edges. Upstands, parapet junctions, drain outlets and penetrations for services are where the detailing has to be right, and where it usually is not. Water also finds failures that only open under load or in heat, which is why a visual inspection alone rarely settles it.
How leak detection finds the real sourceYes. Standing water accelerates membrane breakdown, loads the structure, and turns a small defect into a continuous one because there is always water sitting on it. Ponding is usually a falls or a drainage problem rather than a membrane problem, so re-coating over it buys a year or two at most.
AS 4654 covers external above-ground waterproofing, which is what applies to roof decks, terraces, podiums and balconies. It sets out the detailing at junctions, upstands and penetrations as well as the membrane itself.
Yes, and most of ours is. The programme is staged around access, residents and any plant on the roof, and we set that out with the manager before starting. As a registered building practitioner we can also carry out the associated concrete repair and making good, so there is one contractor coordinating the disruption rather than several.