SEMINAR ONWATERPROOFING TECHNIQUES

CONVECTIONAL

SANCHIT AGRAWALROLL NO- 42

INTRODUCTION

• Water infiltration causes major problems to a structure. Water damages a building first cosmetically then structurally. Hence to keep our building safe & healthy water proofing is an important activity.

• It maintains appearance of building• Increases life of structure• Keeps away foul smells which may arise due to

dampness• Also check the algae & plant development

Sources of Dampness:

1.Geological & climatic causes:• Rain penetration• Ground moisture rise• Drainage of the site• Orientation of the building• Atmospheric moisture2. Structural Causes:• Water introduced in the structure during construction• Defective construction

Prevention:

Basements:• Underground water reservoirs & basements

have to be made proof against leakage or seepage of water as follows:

a)From inside the structure to the surrounding ground, and

b)From the surrounding ground towards the inside of the structure.

Suitable precautions shall be taken to avoid cracks and leakages resulting from the following:

• Movements due to shrinkage and creep,• Movements due to variation of temperature and

humidity.• Movements due to dissipation of heat generated

by the concrete in the process of hydration,• Damage to the concrete by the percolation of

chemically aggressive liquids from outside,• Damage due to uneven settlement of foundations,• Cracking of concrete caused by rusting of bars.

IMPREGNATION WATER PROOFING (PRE CONSTRUCTION) TREATMENT (BOX METHOD)

CITATIONa. R.C.C. WALLb. R.C.C. FLOOR SLAB/ RAFTc. LEAN CONCRETE BASE (1:5:10, 1:4:8, 1:3:6)d. 20mm THICK “ACRYLIC COMPOUND MIXED’ WITH CEMENT MORTAR 1:4 WITH STONE AGGREGATE (12mm DOWN) EMBEDDED AT RANDOM.e.15 TO 20mm THICK ROUGH QUARRY STONE SLABS OVER 15mm ACRYLIC COMPOUND MIXED CEMENT MORTAR 1:4.

f. 20mm THICK ‘ACRYLIC COMPOUND MIXED WITH CEMENT MORTAR 1:4 WITH STONE AGGREGATE (12mm DOWN) EMBEDDED AT RANDOM.

g. 15-25mm THICK ‘GAP BETWEEN STONE SLABS GROUTED WITH ACRYLIC MIXED CEMENT GROUT.

h. 15-20mm THICK ;ACRYLIC COMPOUND MIXED GROUT.

i. 15-20mm THICK ROUGH QUARRY STONE SLABS.j. 15-20mm THICK ‘ACRYLIC COMPOUND MIXED

CEMENT PLASTER 1:4.

Work Procedure:• Over P.C.C. base coat of 1:4 cement mortar shall be laid.• 600 X 600 rough quarried 32-40 mm thick stone slabs laid

over with a minimum width of joint between two tiles.• After fixing stone slabs, joints shall be grouted with cement

slurry & seal them with 1:4 C.S. mortar.• Over this layer joint less layer of mortar shall be laid @25 mm

thick& 1:3 C.S. mortar.• In sumps & gutters this process shall also be done.• Over the plastered stone slab, R.C.C. Raft is laid & walls are

erected.• Rough stone slabs then fixed on outside plane of R.C.C. walls

over neat cement paste up to 450 mm above the ground.• Joints then sealed with 1:2 C.S. mortar, process is called

Pointing.

Continue……

• Grouting is done with cement slurry for 3-4 days until back of stone slabs are completely filled @ 1.5 bag of cement in 100 litre water.

• Curing is required for 7 days at least @ 10 times a day.

• Final joint less waterproof plaster coat in 1:4 C.S. mortar is done over rough stone slabs.

TREATMENT INTERNAL TANKING IN MASTIC ASPHALT (POST TREATMENT)

Terrace:• Terrace is major

point of getting dampness & water into building as it is directly exposed to the weather conditions. Besides doing water-proofing of the terrace, some precautionary measures shall also be taken in consideration.

Preparation of terrace water-proofing:

• Chisel extra mortar on terrace.• Clean terrace with water.• Spread cement slurry @1bag in 100ltr water• Ensure correct location of RWP• Collect brick-bats & soak them before use.

Brick Bat Coba Coat for Terrace Water-Proofing:

• Fix in the slope required, keeping minimum thickness of 65mm.

• Fix in position brick bats using 1:6 C:S mortar in a slope of 1:150.

• Fill in cement mortar 1:4 with water-proofing compound in the brick bat joints.

• Round shape near RWP & corners is essential.• Curing for at least 7 days is necessary.

Final Coat for Terrace Water-Proofing:

• Spread cement mortar 1:4 along with water-proofing compound over brick bat coba.

• Press the cement mortar with a ruler of length of 2 m.• Level the surface with a wooden float, keeping 25 mm

thickness.• Apply thick cement slurry with water-proofing compound

for a smooth finish.• Make vertical & horizontal lines @30cm X 30cm with 3mm

thick dori.• Clean & cure the final coat for at least 21 days, with

6”water standing over water-proofing.

Toilets & Bathrooms:In toilets dampness may take place due to various

reasons, primarily it may leak due to:• Poor workmanship in drainage & water supply

system• Bad quality material used for the purpose of drainage

& water supply

Preparation for W.C. Water-Proofing:

Completion of internal plaster of walls, leaving a margin of 18” from final floor level of W.C. unit.•All grooving/chasing of concealed pipes/ conduits done.•Remove all debris & chisel out extra mortar.

Water-Proofing Process:• Provide 25-40 mm

thick 1:4 cement mortar base coat @ 1:100 slope towards drain pipe.

• •This coat is applied on walls upto450mm ht.

• •It should cover all exposed surfaces of beams, walls .

• •Water is filled for 4 days for curing & testing.

Water Escape Pipe:• Provide 25 mm G.I./ P.V.C. pipe for water

escape outlet.

Brick Bat Coba:Well burnt brick bats soaked and then laid on the base(brick on edge).•Gaps should be filled with 1:6 cement mortar.•Slope of 1:100 shall be maintained.•All the pipes & connections shall be made water-proof.•Curing for four days is required.