The waterproofing of suspended floors and roof to structures involves the use of an overall impervious membrane to carry away surface water and seepage through the finishes to the galleys and outfalls.
The critical nature of the waterproofing on suspended or elevated slabs requires that particular attention be pointed to the following points:
- The surface to be waterproofed must be given adequate falls to drainage points either by slabs to falls or screed falls.
- The waterproofing around galleys should be detailed to provided drainage at both surface and membrane levels.
- Particular attention should be paid to the correct positioning and detailing of expansion joints to allow them to occur at the highest point of the fall. it’s essential that up stands be provided at joints to create a completely waterproof tray on each side with parapet flashing or traditional metal counter flashing.
- Particular attention should be paid to the termination of the membrane at the up stands. parapet and around openings.
The membrane should be protected immediately against damage, ultraviolet degradation and temperature extremes with one of the following material:
- Parapet flashing surface mounted counter flashing.
- Insulation boards for inverted or protected membrane roof, or other approved protection.