How to set up Dam Proof Course (DPC) in construction
Damp proof course (DPC) is specifically used at basement levels to control the motion of moisture via walls and floors. Described below, the detailed procedures for selecting materials for damp proof course and different usages in buildings.
Materials for Damp Proof Course (DPC): Properties of Materials for DPC.
An operative damp proofing material should contain the properties discussed below;
Have good strength and longevity, and the capacity for resisting both dead and live loads devoid of any damage.
Should contain perfect dimensions.
Does not include any deliquescent salts like sulphates, chlorides and nitrates.
Types of Materials for Damp Proof Course - The materials generally utilized to examine dampness and belong to the following three categories:
Compilant Materials: Materials similar to bitumen felts (which refer to hessian based on fiber/glass fiber based), plastic sheeting (polythene sheets) etc.
Semi-rigid Materials: Materials same as mastic, asphalt, or combination of materials or layers.
Rigid Materials: Materials corresponding first class bricks, stones, slate, cement concrete etc.
Selection of Materials for Damp Proof Course in Buildings
Careful selection should be made so that the chosen material can operate as a strong damp proof course. The selection is made on the basis of the climate and atmospheric conditions, nature of structure and the condition where DPC should be delivered.
Selection of DPC materials are based on the following conditions :-
1. DPC above ground level: For DPC above ground level that contains wall thickness usually below 40 cm, any type of materials stated above, are used. Cement concrete is mostly recognized material for DPC at plinth level, 38 to 50mm thick layer of cement concrete M15 (1:2:4 mix) fulfills the purpose under normal conditions.
For the damp and moist environment, consolidated mix of concrete should be used. The concrete can also be thicker if water proofing materials like Pudlo, Impermo, Waterlock etc. are included in its ingredients throughout the mixing process. Two coats of hot bitumen should be applied over the third surface of the concrete DPC.
2. DPC Material for floors, roofs etc.: If the wall thickness is long or DPC should be extended to a greater areas like floors, roofs, etc., the choice is restricted to flexible materials which deliver lesser number of joints like mastic, asphalt, bitumen felts, plastic sheets etc.
If the felts are applied, they should be perfectly stuck to the surface with bitumen and placed with joints accurately lapped and sealed.
To read the complete article, go through the following link theconstructor.org