Case 4

Good Practices

Design

Can use an inverted roof so that waterproofing membrane is protected from heavy traffic. The insulation layer is above the waterproofing membrane which protects it from the traffic movement.

Construction

The membrane should be applied to cover the whole roof and have an upturn of at least 300mm and tucked into parapet wall.

There should be a water-tightness test carried out after the membrane has cured for at least 24 hours. The minimum flooding period should be 24 hours. No dampness should be observed within an hour after the test duration.

If performed membrane is used, all areas laid should be checked for air trapped between it and the concrete surface or between successive layers of the membrane. This is to ensure there is no gaps in between the two layers which would allow water to accumulate.

End laps of the preformed membrane should be at least 150mm and the side laps should be 100mm unless otherwise stated by the manufacturer. End laps between each roll should be staggered.

Liquid-applied membrane should be protected from the rain during application and initial curing. The liquid applied membrane should be laid according to the manufacturer’s specifications. Even though the membrane will be applied by the specialists themselves, some supervision would be necessary as general workers would be performing work.

Materials

Liquid-applied electrometric materials may be used as exposed coatings on roofs or floors for pedestrian or wheel traffic as it can return to its original shape after undergoing stresses.