The Damptec structural waterproofing experts have recently completed a project on a podium deck in accordance with the Koster Aquatecnic specification for podium decks. We ensured that before any installation of materials the substrate was clean, dry and smooth. This is due to the potential of de-bonding when using this method. The concrete needs to be at least 7 days old and of suitable compressive strength. We sprayed Koster Polysil TG 500 and allowed 45 minutes to cure. The team then installed Koster Repair Morter fillets around the perimeters with Koster SB Bonding Emulsion mixed into the first fresh layer. We applied Koster NG1 Grey using a block brush across the entire deck and up to termination level on the walls. We used two coats and it is important to ensure that the first coat has dried before applying the second.
Once all preceding coatings had fully cured we mixed and applied Koster NG4000. We installed Koster Glass Fibre Mesh below the surface of the applied Koster NG4000 and allowed to cure afterwhich we applied a second coating. We laid a thin gauge PE foil (Visqueen) over the cured Koster NB4000 and then laid the Delta Terraxx membrane. Terraxx is a dimpled sheet with a geotextile layer which acts as a surface layer. This usually serves as a green roof external drainage layer which also protects the primary waterproofing applied to substrate. Finally we laid a minimum 50mm screed followed by re-bedding of porcelain tiles.
There must be adequate drainage designed into the system. It is vital to use a suitably qualified professional for the design. Note – any potential risk of ponding must be avoided!
An overflow must always be included for a roof that is encapsulated on all 4 sides. This will allow for drainage should the outlets become blocked. All overflow ports and drainage elements must be both accessible and serviceable to prolong their useful service lives.
- Koster Polysil TG500
- Koster NB1 Grey
- Koster Repair Mortar Plus
- Koster SB Bonding Emulsion
- Koster NB4000
- Koster Glass Fibre Mesh
- Delta Terraxx Protection Membrane