DAMP PROOFING MATERIALS

MATERIALS FOR DAMP PROOFING

 Bricks: Good bricks having water absorption less than 5% are used to make

damp proof courses. These bricks are laid in two to four courses in cement mortar.

 Bituminous or asphaltic felt: These materials are flexible and available in rolls. These are usually applied on roof slabs and parapet walls with an overlap of 10 cm on both sides. These laps are then sealed off with bitumen. They cannot withstand heavy movements.

Mortar: Cement mortar with proportion 1 : 3 with a little  lime and water proofing

Compounds are used to make a water proofing course for ground floor slabs, foundations, top of

parapet walls etc. It may be used for plastering external walls as well

Mastic asphalt: It is a semi rigid material. It is obtained by heating asphalt with mineral fillers and

Sand. It is highly impervious. It should be laid very carefully.

Bitumen: It is highly flexible in hot condition. It is applied with brush to the bedding

of concrete or mortar. Thickness of coat provided is about 3 mm.

Stones: Stones like slates, granites and traps is  laid over wall to its full width as damp

Proof course.

 Concrete: Course of 75 mm to 100 mm cement

Concrete 1 : 1.5: 3 or 1 : 2 : 4 is provided before starting constructing walls  to check the rise of water into walls a. These courses may be provided with hot bitumen paint as an additional precaution.

Metal sheets: Aluminium, lead or copper sheets are provided to seal the construction joints.

Over these sheets bituminous seal is provided.

Plastic sheets: Plastic sheets are very good course for damp proofing. They are usually composed  of a black polythene sheet of 1mm thickness