Transcript 4 methods of damp proofing

causes of fire &precaution:
The variouscauses of fire are as follows:
1.
Careless smoking.
2.
Faulty electrical wiring or short circuiting.
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D. Treatments to basements in
damp soils
E. Treatment to floors
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Concrete has history of good performance in fire
 Concrete is non-combustible and has low thermal
conductivity
 Concrete maintains cool inner core during many
fires which maintains load
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OVERVIEW OF DAMP PROOFING
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Damp proofing is defined by the American Society for Testing
and Materials (ASTM) as a material that resists the passage of
water with no hydro-static pressure and waterproof as a
treatment that resists the passage of water under pressure.
Generally damp proofing keeps moisture out of a building where
vapor barriers keep interior moisture from getting into walls.
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METHODS OF DAMP PROOFING
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Membrane damp proofing :
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This consists of providing layer or membrane of repellent material between the source
of dampness.
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This layer of damp-poof course consists of materials like bituminous felts, mastic
asphalt,silicon, epoxy,polymers,plastic orpolythene sheets, cement concrete etc.
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A damp-proof course (DPC) is a barrier in a masonry wall designed to resist
moisture rising through the structure by capillary action such as through a
phenomenon known as rising damp. The damp proof course may be horizontal or
vertical. A DPC layer is usually laid below all masonry walls, regardless if the wall is
a load bearing wall or a partition wall.
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MEMBRANE DAMP-PROOFING
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D.P.C may be provided horizontally or vertically in floors, walls, etc.,
depending upon the source of dampness.
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A damp-proof membrane (DPM) is a membrane material applied to
prevent moisture transmission.
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Integral damp – proofing :
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Integral damp proofing in concrete involves adding materials to
the concrete mix to make the concrete itself impermeable.
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This consists of adding certain water – proofing compounds with the
concrete mix to increase its permeability. These compounds are available
in liquid or powdered form.
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The compounds like alkaline silicates, aluminium-sulphates, calcium
chlorides, etc. reacts chemically , when mixed in concrete to produce
water proof concrete.
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Pudlo, Permo, Impermo, etc are the commercially prepered waterproofing compounds which are added to cement.
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INTEGRAL DAMP PROOFING
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3)
Surface treatment :
This treatment consists of filling up the pores of the surfaces through which
moisture enters.
The use of water repellent metallic soaps, such as calcium and aluminium
oleates is much effective in protecting the building against the heavy rain.
In addition to these, the cement lime plaster (1:1:6) is done to prevent the
dampness in the walls due to rain.
4) Cavity wall construction :
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This is an effective method of damp – prevention, in which the main wall of
the building is shielded by an outer – skin wall leaving a cavity in between the
two.
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Cavity wall construction, such as rainscreen , construction, is where the interior
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walls are separated from the exterior walls by a cavity
5) Guniting :
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This treatment consists of depositing an impervious layer of rich cement mortar over
the surface to be water proofed.
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The cement mortar (1:3) to (1:4) is shot on the prepared surface under a pressure of 2
to 3 kg/cm². The nozzle of the cement gun is kept at s distance of 75 to 90 cm. from the
working face.
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The treated surface ids then cured for atleast 10 days.
6) Pressure grouting :
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This consists of forcing the cement grout, underpressure , into the cracks, voids,
fissures, etc. present in the structural components of the building or in the ground.
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This method is quite effective in checking the seepage of raised ground water through
foundations and sub-structure of a building.
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MATERIALS USED FOR DAMP-PROOFING
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Materials widely used for damp proofing include:
Flexible materials like butyl rubber, hot bitumen, plastic sheets, bituminous
felts, sheets of lead, copper, etc.
Semi-rigid materials like mastic asphalt
Rigid materials like impervious bricks, stones, slates, cement mortar or cement
concrete painted with bitumen, etc.
Stones
Mortar with waterproofing compounds
Coarse sand layers under floors
Continuous plastic sheets under floors
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DAMP-PROOFING TREATMENT IN BUILDINGS:
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The various damp – proofing treatments in buildings are as follows:
Treatment to foundations
a) Treatment to foundations on ordinary soil
b) Treatment of foundations on damo soil
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c) Treatment to basements in ordinary soil
d) Treatment to basement in damp soil
Treatment to floors
Treatment to walls
Treatment to flat roofs
Treatment to parapet walls
Treatment to pitched roofs
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1) Treatment to foundation:
(a) Treatment to foundations on ordinary soil :
In case of building foundations on ordinary soil ,where the subsoil water table is not high
,brick masonary below ground level can absorb moisture from adjacent ground $ make the
wall damp by capillary action.
This can be prevented by providing DPC ,atleast 150mm above groundlevel or plinth
level.
(b) Treatment of foundations on damp soil :
In case of building constructed on damp soil in wet areas ,the wall as well as the ground
floor are liable to become damp due to capillary rise of moisture from ground.
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In such case the DPC ,is laid over the entire ground floor area including wall thickness, as
A. Treatment to foundations on
ordinary soil
B. Treatment to foundations on
damp soil
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(c) Treatment to basements in ordinary soil:
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In case where the subsoil watertable is low, & there is no water pressure, a
horizontal DPC over the entire area of floor & vertical DPC on external
faces of the basement walls is provided as follows;
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Apply hot bitumen at the rate of 1.5kg/m² over the prepared surface as
primer coat
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Lay bitumen felt in single layer over primer coat.
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C. TRAETMENT TO BASEMENTS IN ORDINARY SOIL
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(d) Treatment to Basement in Damp soil :
 In case where the ground watertable is high , the PDC of beasement is
provided in three ways:
1. Provision of foundation, drains &DPC.
2. Provision of RCC raft & wall slab & DPC.
3. Water proofing treatment by using grout consisting of mortar admixed with
acrylic based chemicals alongwith stone slabs.
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Treatment to Floors:
 The stone soling laying is provided & rammed properly.
 The floor topping comprise of tiles, stones & cement concrete is provided.
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(f) Treatment to walls:
 The moisture may enter from the external face to the internal face of
the wall due to the porosity of bricks & mortar joints.
 The various treatments can be given to the exposed surface of the
wall, to prevent dampness include plastering, pointing &painting etc.
 The plaster made out of cement lime & sand mixed in proportion of
1:1:6 mat be very effective to protect the walls against dampness in
normal weather conditions.
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F. TREATMENT TO WALLS
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REFERENCES
Building construction by A.S.Kotadia
 Building Construction by B.C. Punamia
 Google : Wikipedia
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Thank you…
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