Waterproof and Design Trafficable Car Park Roof Decks
Design car park roof decks that stand up to heavy use and wet weather while keeping the structure dry and durable.
1
Dry Interiors – Protect rooms beneath from water ingress and leaks.
2
Durability Under Load – Use membranes rated for heavy traffic and abrasion.
3
Low Maintenance – Select products designed for easy long-term upkeep.
What Makes Car Park Roof Decks Challenging to Waterproof
Waterproofing car park roof decks requires solutions that go far beyond typical membrane performance.
Unlike residential or pedestrian decks, these structures must withstand constant vehicle loads, turning forces, fuel and oil exposure, and long-term UV exposure.
In New Zealand's coastal climate, where heavy rain and fluctuating temperatures are common, carpark waterproofing systems must also cope with expansion, contraction, and ponding.
The risk of water ingress into occupied spaces below makes the stakes even higher. Successful systems must be robust, trafficable, and capable of long-term protection without failure at joints or drains.
Membrane Systems Designed to Withstand Vehicle Load and Movement
Membranes used under car park decks must be abrasion-resistant, crack-bridging, and resilient to chemical attack.
Elastomeric systems (such as torch-on bitumen or liquid-applied polyurethanes) are often used due to their flexibility and durability. Bitumen membranes must be protected by a wearing layer, either concrete or asphalt.
Liquid membranes do not require a layer but have higher maintenance costs and must resist the loads applied by turning car tyres.
All systems must also tolerate deflection and movement across large concrete slabs and integrate with expansion joints, which are common in car park structures.
Related Nuralite Products
Designing for Movement, Drainage and Long-Term Performance
Effective drainage is critical in trafficable car park decks.
Detailing at joints and penetrations is equally crucial: poorly executed joints are a common point of failure in car parks.
Designers should specify expansion joint covers compatible with the waterproofing system and ensure they are properly sealed and maintained.
FAQs
How do I prevent water ingress in a car park structure?
What type of membrane is best for a trafficable parking roof?
How does traffic load affect car park waterproofing systems?
What maintenance is required for waterproofed car park decks?
Can I use asphalt over a waterproof membrane in a car park?
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