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DPC
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Damp Proofing Course
Materials & Details Prepared by: Ar. Ramandeep
Lecture-10
05.09.2014
What is Damping?
Presence of unwanted
moisture in the structure of
a building, either the result
of intrusion from outside or
condensation from within
the structure.
Lecture- 10 | Damp proofing | 05.09.2014
Faults & Defects
Roofs
Beam Roof joint
Beam column joint
Sill- wall joint
Floor- wall joint
Walls
Lecture- 10 | Damp proofing | 05.09.2014
Effects
Reduction in strength of structural components of the building
Unhygienic conditions
Unsightly patches
Softening & crumbling of plaster (lime plaster)
Flooring gets loosened because of reduction in adhesion when moisture enters through the floor.
Lecture- 10 | Damp proofing | 05.09.2014
METHODS OF DAMP PROOFING
Use of DPC- membrane damp proofing
Integral damp proofing
Surface treatment
Cavity wall construction
Pressure grouting
Lecture- 10 | Damp proofing | 05.09.2014
Membrane damp proofing
Consists of introducing a water repellent
membrane or DPC
between the source of
dampness & part of
building adjacent to it.
Use of DPC- membrane damp
proofing
Integral damp proofing
Surface treatment
Cavity wall construction
Pressure grouting
Lecture- 10 | Damp proofing | 05.09.2014
Membrane damp proofing
May consist of flexible materials such as
1. Bitumen
2. Mastic Asphalt
3. Bituminous felts
4. Plastic/ Polythene
sheets
5. Metal sheets
6. Cement concrete etc
Use of DPC- membrane damp
proofing
Integral damp proofing
Surface treatment
Cavity wall construction
Pressure grouting
Lecture- 10 | Damp proofing | 05.09.2014
Integral damp proofing
Adding certain water proofing compounds or
materials to the concrete
mix, so as to make it
permeable
Use of DPC- membrane damp proofing
Integral damp proofing
Surface treatment
Cavity wall construction
Pressure grouting
Lecture- 10 | Damp proofing | 05.09.2014
Integral damp proofing
Compounds made from chalk, talc, fullers earth, - which will fill the concrete voids
Compounds like- alkaline silicates, Aluminium sulphates, calcium chlorides, etc.
Compounds like soap, petroleum, oils
Fatty acid compounds such as stearates of calcium, sodium, ammonium, etc.
Use of DPC- membrane damp proofing
Integral damp proofing
Surface treatment
Cavity wall construction
Pressure grouting
Lecture- 10 | Damp proofing | 05.09.2014
Surface treatment
Application of a layer of water repellent substances or compounds on these surfaces through which moisture enters.
Water repellent metallic soaps such as calcium & aluminium oletes & stearates (effective for rain water penetration)
Use of DPC- membrane damp proofing
Integral damp proofing
Surface treatment
Cavity wall construction
Pressure grouting
Lecture- 10 | Damp proofing | 05.09.2014
Cavity Wall construction
Effective method of damp prevention
Main wall of building is shielded by an outer skin
wall, leaving cavity between
the two.
Use of DPC- membrane damp proofing
Integral damp proofing
Surface treatment
Cavity wall construction
Pressure grouting
Lecture- 10 | Damp proofing | 05.09.2014
Pressure Grouting
Consists of forcing cement grout, under
pressure, into cracks,
voids, fissures etc.
Structural components and foundations are
liable to moisture
penetration
Use of DPC- membrane damp proofing
Integral damp proofing
Surface treatment
Cavity wall construction
Pressure grouting
Lecture- 10 | Damp proofing | 05.09.2014
Grouting Procedure
Lecture- 10 | Damp proofing | 05.09.2014
Guniting
Depositing, under pressure, an impervious layer of rich cement mortar over exposed surfaces for water proofing, for resisting water pressure.
Cement mortar ratio- 1:3 cement sand mix.
Shot on cleaned surface- with cement gun, under pressure- 2 to 3 kg/cu cm.
Use of DPC- membrane damp proofing
Integral damp proofing
Surface treatment
Cavity wall construction
Pressure grouting
Guniting
Lecture- 10 | Damp proofing | 05.09.2014
Lecture- 10 | Damp proofing | 05.09.2014
Materials used
Hot Bitumen Highly flexible material
Min. thickness- 3 mm
Placed on concrete bedding
Mastic Asphalt Semi rigid material
Durable and completely impervious
Obtained by heating asphalt with mineral filler & sand
Liable to squeeze out in very hot climate/ heavy pressure
Lecture- 10 | Damp proofing | 05.09.2014
Materials used
Bituminous or asphaltic felts Flexible material Available in rolls of various wall thickness Laid on levelled flat layer of cement mortar Cannot withstand heavy loads Can accommodate slight movements
Metal Sheets Sheets of lead, copper, aluminium Flexible Thickness should be such that weight is not less than 20 kg/
sq mt
Laid similar to bituminous felts.
Lecture- 10 | Damp proofing | 05.09.2014
DPC Treatment for basement on undrained soils.
Lecture- 10 | Damp proofing | 05.09.2014
Plan of building showing DPC
Lecture- 10 | Damp proofing | 05.09.2014
DPC treatment for basement in damp soil
Lecture- 10 | Damp proofing | 05.09.2014
DPC for flooring
Lecture- 10 | Damp proofing | 05.09.2014
Asphalt tanking for basement