How To Waterproof Buried Roofs and Podium Decks

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How To Waterproof Buried Roofs and Podium Decks

The structure over the basement is often overlooked from a waterproofing perspective and requires careful design and the correct waterproofing system.

Podium decks and buried roofs firstly need to be sealed against surface water ingress from above.

We prefer to use liquid applied waterproofing systems for this purpose due to the lack of seams and joints that are weak spots for leakage and failure.

For buried roofs we recommend Koster Deuxan 2c due to its great crack bridging capability. Cracks up to 2mm can be bridged if reinforced using Koster Glass Fibre Mesh.

For exposed balconies or podium decks where a thinner build up is required we recommend Koster 21 or Koster NB4000. These products are great as they allow for direct bedding of tiles or paving slabs and are UV stable and can take light foot traffic so they could even be left exposed.

We typically recommend that the waterproofing layer is both drained and protected against damage during the backfill process. Here we would recommend Delta Geodrain Quattro. This offer great impact protection and speeds the movement of surface water away to the drainage outlet.

If the deck is buried and access is not possible to externally seal the sides then it will be necessary to provide extra detailing to the underside of the deck to prevent water tracking in from the sides.

Fillets can be formed using Koster Repair Mortar Plus at the internal wall-soffit junction and Koster NB1 applied to the underside of the deck to provide a continuous barrier.

Below ground construction joints can also be protected withe use of Koster Quellband waterbars.