Roof Waterproofing Demands:
- A system which can allow to take the movements in structure.
- A system that can allow itself to carry heavy intense built-ups such as – landscaping or gardens or ballast / pavers etc.
- A system robust enough to take pedestrian / vehicular traffic
- A system that can used to refurbish roofs without disturbing or breaking off the existing substrate
- A system that can be left exposed to atmosphere.
- A UV stable system
- A system with reliability and aesthetics.
- A system that demands to be laid loose or unbonded to the substrate.
- Long-life expectancy and maintenance free or minimal maintenance.
- A complete water-tightness
Prevailing Roof Waterproofing Practices & Viewpoint:
Rigid waterproofing barriers: A conventional practice of rigid waterproofing such as brick-bat koba and crystalline waterproofing has limitation if structure is design to undergo movements during life span.
Flexible & elastomeric waterproofing membranes: This type of waterproofing forms a membranous barrier against water leakage
They are as follows:
a] They come in form of liquids, either single component or multi-component, applied wit hand or spray. They could be cementitious polymer modified or acrylic or P.U. based or bituminous or epoxy based.
b]They come in form of preformed membranes either made up of modified bituminous membranes (APP, SBS), PVC, TPO, HDPE, EPDMs etc. they are either torch applied, stuck with adhesive, mechanically fixed.
Rigid waterproofing barriers have shown limitation or failure when subjected to certain aggressive conditions or structural movements during its life span. Bituminous / cementitious polymer modified EPDM membranes / HDPE based systems do enable elongations but have limiting success, application difficulties and deteriorate with time in
limited life span of application.
The reasons of failure of systems are many, it could be wrong system application or the behaviour & limitations of the material itself in terms of adhesion or UV stability etc. Over a period of time excellent development for different types of water proofing materials and system have been taking place, keeping in mind the criteria or requirements for a good engineered & reliable Roof Waterproofing System.