Most podium and car park leaks come from four places: failed expansion joints, a worn or cracked deck coating, blocked or broken drains, and cracks in the slab. For an owners association, the job is to find which of these is failing, approve a scope that fixes the cause, and phase the work so residents and shops can keep using the building.
The usual causes
- Expansion joints. The joints that let the slab move are the most common leak point. Old seals harden, split or pull away, and water runs straight through.
- Deck coating. Traffic, turning tyres and sun wear the coating thin. Once it cracks, water reaches the slab and finds its way down.
- Drains. Blocked or cracked drains make water pond on the deck, and the joint between the drain and the coating fails.
- Slab cracks. Shrinkage and movement cracks let water drip through to the level below, often with rust staining.
Step 1: a condition survey
Before asking for quotes, get a written survey. It should map every leak point, record moisture readings, assess the coating, joints and drains, explain the likely causes, and give a prioritised scope. This is the document a board needs to approve spending, and it lets you compare contractors on the same scope.
Step 2: decide the scope
- Local repairs: a few failed joints or drains, with the coating otherwise sound. Resealing joints and injecting cracks may be enough.
- Joint renewal: many joints failing across the deck. Renew all of them in one programme with expansion joint sealing.
- Full deck system: the coating is worn across the area. Shot-blast, repair the concrete, renew the joints and apply a trafficable PU or polyurea system, then reinstate the line marking.
Fixing only the visible drips usually moves the leak somewhere else. Fixing the cause costs less over the life of the building.
Step 3: plan the phasing
- Split the deck into zones and close only one at a time.
- Give residents and tenants the bay closures and dates in advance.
- Use night or weekend shifts where noise and access allow.
- Agree curing times before reopening each zone to traffic.
Step 4: approvals and access
In jointly owned buildings, podiums and car parks are normally common areas, so the work is approved and funded through the owners association and its management company. Confirm the building's own approval process, any free zone or master developer permit for site work, and access arrangements before the start date.
Step 5: handover records
Ask for a handover file: the products used, photos of every layer, test results where the surface allows, and a drawing of what was repaired. It is the record future boards and FM teams will need.
Getting quotes the board can compare
Give every contractor the same survey and scope, ask each to price the same phasing, and compare what is included: preparation, joints, drains, line marking and the handover file, not only the price per m².
We survey podiums and car parks, provide a written condition report and phase the work around the building. See podium and car park waterproofing and our commercial waterproofing page, or send photos of the leaks and the deck on WhatsApp.