There are different materials, which are used as damp proof courses depending on location, economy and degree of damp proofing required. However, when choosing a particular damp proofing material, the following requirements for an ideal damp proofing material should be kept in mind.
Materials for DPC must be impervious and durable, meaning the material must be effective throughout the useful life of the building.
The material must be able to withstand both dead loads and superimposed loads without breaking.
The material must remain stable in its position without movement, so that no cracks occur in the walls above the DPC.
For DPC above ground level, with wall thickness up to 40 cm, any of the materials listed below can be used for DPC.
For laying DPC over large areas, such as floors and ceilings, and over thick walls, a DPC material should be used that provides fewer joints, such as mastic asphalt, bitumen sheeting and plastic sheeting.
Materials for parapet walls and other situations where thermal movement due to exposure is expected should be flexible materials, such as mastic asphalt, bituminous felt and metal sheets.
In water retaining structures or situations, jointless DPC should be provided to take care of leakage risk.
In cavity or hollow walls, the cavity over door or window openings should be filled with flexible materials, such as bitumen sheet, lead and copper strips.
Commonly used materials for DPC are listed below.
Flexible materials: hot bitumen, bituminous felts, bituminous sheet, plastic sheet (polythene sheets), lead metal sheets, copper etc.
Semi-Hard Materials: Mastic asphalt or combination of materials or layers.
Hard materials: Use of I class bricks, stones, slates etc.
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