WATER LEAKEGE REMEDIES AND

PRECAUTIONS IN RCC STRUCTURE

-: Index:-

No. TOPICS PAGE NO.1 Introduction

1.1 Water Leakage in RCC Structure

1.2 Meaning of the Term

2 Types of Terracing

2.1 Types of Terracing

3 Slab Leak

3.1 How to Detect a Slab Leak?

4 Leaks From Terrace

4.1 Instructions

4.2 Terrace Precautions

5 How to Control Roof Leaks

5.1 Instructions

5.2 Locate the Leak from Inside

5.3 Control the Damage

5.4 Locate the Leak From Outside

6 How Water Damages a Ceiling

6.1 Instructions

6.2 Supplies and Tools Needed to

Repair a Water Damaged Ceiling

6.3 Stop the Source of the Water

6.4 Dry Above and Below the Water

6.5 The Mold Danger

6.6 Remove the Damaged Ceiling

6.7 Prepare the Surface of the Ceiling

6.8 Cover the Stain on the Ceiling

6.9 Paint the Ceiling

6.10 Apply Texture to the Ceiling

7 Waterproofing

System

7.1 An introduction to waterproofing

systems

7.2 Chemical waterproofing

7.3 Coatings/membranes

7.4 Polymer flexible slurries

/membranes

7.5 Elastomeric coating/membranes

7.6 Impregnates

8 Water leakage in building

8.1 Leakage & dampness in buildings

8.2 Precaution during construction of

building

9 Water proofing

9.1 What is water proofing?

9.2 Concert water proofing by

crystallization

9.3 water proofing compound

CHAPTER 1:- INTRODUCTION

1.1:- Meaning of the term:

The term water leakage in the buildings is used to mean the coming out of water from

components like walls and floors of the buildings. It is observed in the building industry that

99% (percent) of water leakage problems are concentrated on the terrace roofs and in the toilets.

The water leakage in the buildings is the most common problem particularly in all types of

buildings such as residential flats, hospitals, offices, school buildings, etc.

1.2:-Reasons and preventive measures for water leakage:

It is necessary to prevent water leakage in the buildings so as to provide healthy and happy

environment. It will also avoid damages to household articles, Costly painting and short

circuiting of electrical wiring. The defects which cause water leakages in the buildings can be

grouped in the following three categories:

(1) Defects due to poor maintenance

(2) Defects in construction

(3) Defects in design.

Each of the above categories of defect will now be briefly des-cribbed.

1.2.1:-Defects due to poor maintenance:

The neglected maintenance along with weathering and aging leads to the water leakage in the

existing buildings. The flowing water is dynamic and rushes through valves, traps, washers, taps

and cocks situated at several places in the building. These things are subjected to constant wear

and tear. They therefore require periodical maintenance. As such, non-repairing attitude proves

detrimental to the safety of the structure. Following are the measures to be taken to minimize

water leakage due to poor maintenance:

• Filling of joints: The joints in the drainage system should be filled with rich

cement mortar. Due to again, the strength of cement mortar deteriorates resulting in

leakages through the cracked joints. The remedy lies in filling such joints, initially with

epoxy mortar or at least at a later stage while repairing the same.

• Improper use of toilets: It is necessary to educate the public for properly

using the toilet system. For instance, in the drainage system of public hospitals, it is

observed that the patients and their near relatives misuse the toilet systems by throwing

bandages, cotton waste, injection bottles, etc. It ultimately leads to the choking of the

drainage system

• Joints in floor of toilets: The joints in tiles of bath and water closet are

filled with white cement. These joints get loose after continuous use and require

periodical maintenance and sealing with white cement.

• Replacement of taps: The leaking water taps lead to colossal waste of

filtered water and avoidable water leakages in the building. It is therefore necessary to

provide good quality bib cocks initially and go on replacing washers periodically,

whether required or not, as a preventive maintenance measure.

1.2.2:-Defects in construction:

The defects at the construction stage include honeycombing in concrete, use of

defective materials, bad workmanship, etc. The remedial measures to avoid water leakage due to

such defects are as follows:

• Defective concrete: The provision of well designed compacted dense concrete

with proper curing can solve number of leakage problems in a building.

• Door frame joint near toilet: The joint between door frame and flooring

of bath and water closet should be made leak proof by applying epoxy mortar or cement.

• Plumbing: The joints in the plumbing of w.c. seats and nanny traps should be filled

with rich cement mortar and cured for seven days. If curing is not properly done, the rich

cement mortar gets cracked and leads to leakage. If possible, one piece P trap

• Should be used to reduce one joint in the drainage system and it should be fixed before

water-proofing of the W.C. block is started.

1.2.3:-Defects in design:

The defects in planning and design can be avoided in the pre-construction stage by

entrusting the work to Experienced and well trained architect and engineer. Some of the

Measures to avoid water leakage due to faulty planning are as follows:

Design of floor slab: It should be seen that the design of Floor slab and

centering should be such that the local stagnation of water does not occur.

Design of rain water spouts: The rain water spouts of less than 100 mm diameter

should not be used. It is also desirable to provide one spout for every 40 m2 area of terrace.

Fixing of nanny traps: The nanny traps are required for toilets, Kitchen sinks,

washbasins, etc. The niche or pocket of clear size About 300 mm x 300 mm x 150 mm should be

provided to accommodate the nanny traps and their locations should be clearly shown in the

Location of sanitary block: For public buildings like schools, Hospitals,

hostels, colleges, commercial centers, theatres, etc., it is Desirable to detach the sanitary block in

the planning stage only. Such a criteria will help in keeping the building usable even if the

Sanitary block suffers from leakage. It will also avoid the spreading of dampness in the rest of

the building.

• The entire sanitary block should be sunk to a sufficient depth to accommodate the items

of Sanitation. As a matter of fact, the engineer should supply a detailed Plumbing

drawing of the sanitary block showing the slope of pipes, Slope of gutters carrying urinal

effluent, washbasin effluent, general Slope of the toilet flooring, etc.

Relief valves: It is necessary to provide break pressure relief Valves at suitable vertical

distance in multi-storied buildings to prevent seepage of water through the plumbing system.

Slope of terrace slab: The minimum slop of 1 in 100 to 1 in 60 should be clearly

shown on the terrace plan. It will help in adjusting the slope in centering with uniform thickness

of roof Slab. The suitable provision of terrace slope would result in smooth Disposal of

rainwater.

• Water tanks:

For overhead R.C.C. water storage tanks, it should be seen that the permissible limits of

stresses relating to Resistance to cracking are not exceeded. The detailed bar bending

Schedule should be supplied by the designer. The bottom slab of Overhead water tank

should be placed one metre above the roof Slab. It will facilitate proper centering during

construction and also for locating and repairing the leakages after construction.

Water leakage

CHEPTER:-2:- TYPES OF TERRACING

2.1:- TYPES OF TERRACINGS

Proper terracing contributes to a great extent to the waterproofing. Junction

arrangement of a terracing with parapets is of utmost importance. Where a terracing is

not embedded inside the parapet wall as per arrangements in annexure-I, alternative

arrangement is possible to make the joint water proof by arrangements shown in

annexure-V. A brief review of the various types of terracing used and precautions to

be taken are given below:-

2.1.1:- BRICK BAT COBA

This involves lying of 80 – l00 mm thick coba concrete on a prepared surface

with graded broken brick aggregate. Concrete can be lime concrete or cement concrete

with water proofing compound. This is useful for giving the surface the required slope

so as to drain out water quickly. Since brick-ballast is hygroscopic, very good

workmanship, mixing of all the ingredients in correct proportion and adequate

compaction by rammers for lime concrete and by vibrators for C.C. is of paramount

importance.

The brick bed coba is topped with IPS or with China Mosaic.

China mosaic is usually provided over a Coba surface by broken pieces of ceramic,

China or Mosaic tiles are set over bed of cement mortar (1:3, 15mm thick).

2.1.2:- INDIAN PATENT STONES (IPS)

This surfacing is used either as a surface barrier treatment over a new

surface or at a location where the ingress of water has taken place. A 25 – 40 mm thick

layer of cement concrete 1:1:2 (8 mm to 10 mm size stone aggregate) is laid over a flat

surface, giving it a correct slope before IPs is laid on top of the same. Joints on IPs are

filled with a suitable sealant like bitumen, mastic, etc. Leakage may also take place

through the joints which develop cracks with time. IPs can also be provided over coba

concrete.

2.1.3:- MUD PHUSKA WITH BRICK TILES

This treatment usually consists of the following:-

a) 100 mm thick (average) mud phuska consisting of puddle clay mixed with

chopped straw (bhusa) 8-10 Kg. /m3 of soil.

b) Mud plaster of paddle clay mixed with chopped straw 30 to 35 mm long.

c) One or two course of brushing (“leaping”) with fine clay and cow dung in

equal quantity.

d) One or two layers of bricks tiles laid on a bed

mud mortar and jointed and pointed

in cement mortar 1:3.Some time a coat of hot bitumen @ 1.7 Kg./Sq m.

On a polythene sheet can be laid below the mud phuskalayer.Mudphuska

also gives excellent protection from heat.

2.1.4:- LIME CONCRETE TERRACING

This treatment has been used since time immemorial. This treatment is however most

successful where temperature variation is less since the lime concrete itself crack under wide

temperature changes.

Terracing consists of various proportion (which vary with regions) of brick aggregate,

lime surki and sand to make a lime concrete of thickness 75 to 100 mm which is rammed and

subsequently beaten with wooden thappies for three to four days as it slowly

CHEPTER:-3:- SLAB LEAK

3.1:- How to detect a slab leak? Every homeowner should be aware of the signs that point to a possible slab leak in the

foundation, and make sure proper action is taken to repair the slab leak.

3.1.1:- The following check list is a good tool for detecting

slab leaks:

Significant increase in your water or electricity bill: if you notice that your water or

electricity bill suddenly jumps, It may be due to a slab leak.

3.1.2:- Visible wet or damp stains on carpet or flooring: A slab leak can sometimes reach the flooring, creating noticeable spots or stains.

3.1.3:- Reduced water pressure: If you notice a decrease in water pressure, it may be caused by a slab leak.

3.1.4:- Stalling of the foundation: When an actual shifting of the home’s foundation is felt, a slab leak may have occurred.

CHEPTER:-4:- Leaks From Terrace

4.1:- INTRODUCTION

Most of the terraces are laid with brick-lime jelly and pressed tiles or brickbat coba for

providing nominal slopes on the roof slab to drain off water through the rainwater down-take

pipes.

This lime concrete over the RCC is meant for gradation and hydration purpose only and not

used as a waterproofing agent. So, the RCC should be protected with waterproofing system. Since water has a tendency to take the weaker path, the entry of water from the terrace of

even the ninth or 10th floor can be the cause for leaks in the ground floor or any other floor of

that building. Also, leaks may take place through cracks on the top and sides of the parapet walls

leading to entry of water into the building. Improper sealing of the rainwater down take pipes

also leads to water leaks in the walls/slab of the building.

 4.2:-Terrace precautions

Care should be taken to provide proper slopes on the slab to prevent stagnation of water.

All opened-up tile joints have to be filled with a polymer - modified waterproof mortar and

sealed.

Damaged tiles have to be replaced with new ones.

Any exposed concealed pipe-electrical/others on the terrace has to be sealed properly to

prevent water seepage through them into the building.

CHEPTER:-5:- How to Control Roof Leaks

5.1:- Instructions:

Treat a leaking roof as an emergency, because it can wreak havoc in your house in a very

short time. Attend to any signs of a roof leak, such as water entry, stains or mold, immediately to

limit damage. Locate the leak from inside and then take steps to control the damage until you can

have a suitable outside inspection and repair done.

5.2:- Locate the leak from inside:-

1. The first and perhaps most obvious place to look for a roof leak is directly above the leak in a

ceiling or exterior wall. Use a flashlight to inspect the attic floor over the leak while it's raining.

Look for standing water, water stains, mold, wet insulation or other exposed insulation.

2. Examine the underside of the roof for wetness or mold around points of penetration

(plumbing vents, chimneys), wherever different roof planes intersect (valleys) and near dormers.

These symptoms indicate holes in the flashing or faulty flashing installation.

3. A leak away from such locations suggests a problem in the roofing material. Keep in mind

that water may travel sideways before passing through a joint in the roof sheathing, and may

travel in a horizontal joint before falling on the floor or ceiling.

5.3:- Control the damage:-

1. Water can travel on the underside of sheathing or down roof rafters before dropping off in one

or more places. To control where it falls, tack a piece of string into the stream of water and let it

hang into a bucket. The water will tend to follow the string.

2 .Poke or drill a hole in your ceiling to let the water through. This technique prevents the water

from spreading across the top of the ceiling to other areas; it prevents the ceiling from becoming

saturated, eliminating the chance of collapse and often the need for replacement; and it allows

you to collect water from below using the string-and-bucket method.

5.4:- Locate the leak from outside:-

1. Using any measurements or other information you gathered indoors, make your initial

outdoor observations from a ladder and/or using binoculars. Do not walk on a pitched roof

during rain or as long as the roof is wet. A wood roof is particularly treacherous.

2. Look for leaves and other debris slowing the natural downward flow of water, as often

happens in valleys and adjacent to or above any roof penetration or dormer. If there is snow on

the roof, an ice dam may have formed at the roof's lower edge, causing water to back up under

overlapping layers of roofing materials. Remove the obstruction if you can get to it safely.

3. If or when you can safely get close enough, examine metal flashings for corrosion or

open joints where they connect to a chimney or other roof penetration. You can temporarily

patch metal flashings, but replacement is the only permanent solution. Typically, you can replace

cracked or dried-out rubber gaskets on plumbing vents

CHEPTER:-6:- How Water Damages a Ceiling

6.1:- Instructions:-

Water always flows down and always follows the path of least resistance. When water

flows onto a ceiling from above, it looks for the easiest way to keep going down. With drywall,

this is usually where two panels of drywall meet. The water drips through the gaps in the seams.

With plaster, it is usually the place where the water pools up. It saturates the plaster then drips

right through. The ceiling material soaks up the water and changes color. It becomes heavy and

sags. In extreme cases of water damage, huge chunks of the ceiling collapse. Water allowed to

min gle inside your ceiling and walls will grow mold that is very difficult to get rid of once it

starts to grow.

6.2:- Supplies and Tools Needed To Repair Water Damaged Ceiling

You will need several supplies and tools to repair a water damaged ceiling. You may

have to get some or all of the following items:

• · Ladder

• · Towels

• · Vacuum cleaner

• · Fan

• · Screwdriver

• · Bucket

• · Putty knife

• · Paint Scraper

• · Sandpaper

• · Joint compound

• · "Kilz" primer

• · Tarps

• · Masking tape

• · Plastic sheets

• · Paint

• · Canned ceiling texture

6.3:- Stop the Source of the Water

This is the first thing you should do. It does not make any sense to repair a water

damaged ceiling if more water will come in and damage it again. Find out where the water is

coming from and stop any more from getting in. This could require you to fix a roof, replace a

pipe or threaten a neighbor who is leaking water into your home.

6.4:- Dry Above and Below the Ceiling

Once you stop the water from coming in, mop up as much water as you can as quickly as

you can. Dry everything out with towels, vacuums and fans. Do this both above and below the

ceiling. If water is dripping through that means the ceiling is saturated. The ceiling must either be

dried out or the wet portions removed. If the ceiling plaster or drywall is bulging, stab it with a

knife or a screw driver. Be careful. Water may come pouring out. Place a bucket underneath the

bulge before poking it.

Dry Everything Out Quickly

6.5:- The Mold Danger

Mold grows very well in moist and dark places. If you eliminate the water in the ceiling right

away you may be able to stop the mold from sprouting. If you allow the ceiling to be damp for

several days, mold might start growing and thriving. Once mold gets into the interior passages of

home, it is extremely difficult and costly to get it out. Sometimes homes are completely

condemned because mold has taken over. Do not take this lightly. Dry everything out as quickly

as possible. This may require several days with a fan blowing on it. Once the moisture is gone

and you are convinced the water is not coming back, you can begin repairing the water damaged

ceiling.

6.6:- Remove the Damaged Ceiling

Scrape away any pieces of plaster or drywall that are loose, bulging or peeling away. If it

is moist to the touch, tear it out. If it is flaking or chipping, scrape it with a putty knife or paint

scraper until it is flat. If the ceiling is discolored but otherwise flat and unchanged, you do not

need to scrape it.

Severe Ceiling Damage

6.7:- Prepare the Surface of the Ceiling

Use sandpaper to remove the ridge separating the damaged and undamaged areas of the

ceiling. Make this as smooth as possible. Major holes will require new sheets of drywall or

plaster. Repair small holes by filling them with joint compound. Smooth them level with a putty

knife and allow it to dry. Once it is dry, sand it again to remove any bumps. Do this until it is

smooth to the touch and your fingers can not tell where the patch begins and ends. If the ceiling

is only discolored and has no holes, skip this step and move on to the next step.

6.8:- Cover the Stain on the Ceiling

Buy a can of a primer called "Kilz." It covers any kind of stain so it cannot be seen later. If

you just paint over water damage, it can show through the paint or appear later. Kilz looks like

ordinary white paint but does much more. Apply a coat to the stain area and allow drying. Apply

more coats of Kilz if necessary. Be sure to ventilate the room to prevent the buildup of toxic

fumes.

6.9:- Paint the Ceiling

. Secure them with masking tape. Before you begin any large scale painting, spread out tarps on

the ground underneath the part of the ceiling where you are painting. Once the layers of Kilz are

dry, paint the ceiling with a color that matches the rest of the ceiling. If the ceiling paint is old

and hard to match, it may be more efficient to paint the entire ceiling in that room. If you are

painting the entire ceiling, cover furniture and the walls with plastic sheets

6.10:-Apply Texture to the Ceiling

if the ceiling has texture; spray some canned ceiling texture on the damaged area. Wait for it to

dry and see if it matches the rest of the ceiling. Add another coat if more is required. The water

damaged ceiling is now repaired.

CHEPTER:-7:- Waterproofing system

7.1:- An Introduction To Waterproofing Systems:-

Many homeowners find it necessary to invest in waterproofing systems for their

homes, especially if the house has a basement or a cellar. In modern home developments, it is

Often required by state or local regulations to have waterproofing systems installed before the

completion of the home, because without a proper installation of such a system your house is at

risk for water damage or the growth of black mold in prone areas. There are also other factors

that you will have to consider when implementing waterproofing systems such as the landscape,

climate, terrain of the area and the weather.

The waterproofing systems are necessary because normally basements leak for a multitude

of reasons. Water can build up because cracks in the walls or the floor, improperly installed or no

footer tiles, pressure build up from the floor or walls, leaks from sweating basement pipes and

leaks from basement windows and many other reasons. The mold is a dead giveaway that your

basement has leakage or condensation problems. In case you have problems with the black mold

then it is imperative that you seek a professional installer for your waterproofing system.

Another important reason for installing waterproofing systems is the roof leakage. One of

the most popular methods that has been a top choice in roof maintenance for more than 35 years

are the spray polyurethane waterproofing systems. The spray polyurethane waterproof has a lot

of advantages to offer when it comes to protection systems, such as waterproofing/leak

prevention and insulation value, better compressive strength, lightweight and the durable and

long lasting effects, just to name a few.

Buildings incorporate latest scientific methods to ensure perfection in appearance while

waterproofing is done by methods that are centuries or possibly millennia-old. Frenetic speed,

non-availability of quality Construction materials and lack of sincere labor are reasons for poor

structures coming-up of late, says A. C. RAVI RANGASWAMI

Laying of tiles on a waterproofed terrace

CONSIDER a house that you are visiting. It is less than a year old. Its façade is

impressive. Its design is ornate and available space has been skillfully exploited. You admire the

beautiful and apt colors used too. But as you look up, at the ceiling, you find a damp patch in a

corner, spoiling the whole appearance of the room. No expense has been spared to make the

house look grand but have the architect and builder been remiss in bestowing attention on the

durability of the structure? The small patch in the ceiling does not mean that water has leaked

through that spot alone. It means rather, that water spreading over a longer area and through

various channels behind and below the surface, has, for the present, been able to escape to the

surface at that point only. Obviously, stop-gap repair work to clear that blemish will not help,

for, over a period of time, perhaps after the very next shower, the moisture will find other portals

of entry to the surface of the walls and ceilings.

What then, is the source of this evil? Why is this leakage of water, even in new buildings,

a ubiquitous problem in Chennai? The answer is that waterproofing of buildings receives scant,

if any, attention at the time of construction. While other aspects of the building incorporate latest

scientific methods to ensure perfection in appearance and quality, waterproofing is done

following methods that are centuries, possibly millennia old.

In those days, construction was done at a leisurely pace. Curing of concrete/mortar was

given great importance. Curing is one of the most important factors determining the strength and

water tightness of concrete. But nowadays, we witness huge buildings cropping up within a few

months.

The main reason for waterproofing being accorded step-motherly treatment is lack of

awareness of its long-term benefits.

Waterproofing is an integral part of the construction activity and its critical role must be

appreciated. We fail to realize that all the money we spend on aesthetics will go down the drain

if we do not ensure that the house is waterproofed. This is confirmed by the absence of

waterproofing details in the advertisements released by construction companies that provide all

other details, which are physically visible.

Water seepage is just not an inconvenience but also damages your concrete, causing

corrosion of steel reinforcement. Durability of the finished structure relates to concrete's ability

to preserve the alkaline environment around the reinforcement during its service life and to

maintain its structural capacity. The protection of the reinforcement is lost if harmful substances

like chlorides or carbon-dioxide and other toxic gases like nitrogen oxide and sulphuric oxides

penetrate the cover layer along with moisture and oxygen causing corrosion of the re-bars.

Slope-making (with concrete) towards down take pipes

7.2:- Chemical Waterproofing:-

Chemical admixtures are ingredients in the form of powder or liquid, added to the concrete

matrix during mixing. Admixtures are actually no substitute to waterproofing of buildings but

definitely provide many beneficial effects.

7.3:- Coatings/Membranes:-

The advent of coating membranes followed admixtures but unfortunately they are not found

suitable for Indian conditions. In surface coating, the pores and capillaries are blocked,

hampering the natural breathing of the building. The impermeable surface coating allows water

to build up behind the surface coating with the risk of disruption to the coating and possibility of

damage. In fact, trapped water would be moving behind surface coating and wherever it finds

weaker segments, it would come out resulting in cracks and blisters on the surface.

Bitumen or asphalt is widely used as a coating. Bitumen, on attaining high temperature,

particularly in summer, undergoes photo-oxidation, initiated by UV radiation. This results in the

formation of cancer-causing and toxic polyaromatic compounds including Benzopyrene (B) (a

harmful toxic constituent as in cigarette smoke) which have led to the banning of bitumen in

several countries.

7.4:- Polymer Flexible Slurries/Membranes:-

The proportion of polymer in these is at least 40 per cent, expressed in terms of cement. As a

result, the cement no longer forms a firm framework. In fact, the polymer bonds the mixture of

sand and cement to yield a soft and flexible structure.

7.5:- Elastomeric Coatings/Membranes:-

The entry of recent generation of elastomeric coatings/membranes has revolutionized the

waterproofing industry. These elastomers are special class of materials that are flexible and

breathable, with high elongation and weather ability and crack bridging membranes.

7.6:- Impregnates:

Solvent-based impregnates have several problems — Toxicity, hazardous, environmental

pollution, odor and so on. In various countries, there is now legislation in place limiting the use

of organic solvents in the coating and imp regnant industries.

In the West, experts recommend solvent-free aqueous silicone ester emulsion for

waterproofing of external brick walls and exteriors without leaving any patch. At present, this

product is manufactured as well as imported into our country.

A majority of the products available in India are based on the coating technique, while the

latest impregnation technique is offered by only a few companies. Some of the major players in

the waterproofing industry are Forsook, Rife, McBauchemie, Pixilate, STP, Don, Xpedx, Tech-

Dry etc. As far as Chennai is concerned, the coating technique is preferred since it is a one-step

treatment and less time-consuming.

The impregnation technique, which is becoming popular worldwide, is a multi-step

treatment and several civil engineering professionals are really impressed by the results of this

technique and recommend it to their clients. But, it must be borne in mind that application skills

play a very important role in the success of any waterproofing system. It calls for considerable

expertise and specialized labor.

Application of polymer modified coating helps to avoid water

Penetration

CHEPTER:-8 WATLEAKAGE IN BUILDING

8.1:-LEAKAGE & DAMPNESS IN BUILDINGS

Leakage in building, especially roofs has been a cause of concern on the Indian

building. There is hardly any railway building, which does not show signs of leakage.

Apart from inadequate water-proofing, which has been dealt with in detail in these

papers, our failure to observe certain precautions at the time of construction of these

buildings largely results in leaky roofs.

8.2:-PRECAUTIONS DURING CONSTRUCTION OF

BUILDING

Some of the essential precautions to be taken at the time of construction are as

follows:-

i) Every building plan, whether for new building OR for addition/alteration to new

building, must give details of terracing to be provided , water proofing system for roof

with details of joint with parapet wall, sunken `floor and down water pipes in scale not

smaller than 1:20

ii) Specifications laid down by the manufacturers of

the water proofing products should be followed scrupulously to ensure that no air

bubbles are left between the under lying surface and the water proofing layer. Adequate

overlaps should water proofing layers, including cover up to the parapet wall. There are

a large number of relevant Indian Standards Codes of practice available. Their

provisions regarding material & execution may be followed.

iii) Drainage slope of the roof is one of the most important factors. For the guidance of the

field Staff, each building plan must also incorporate a roof plan, showing the position

of drainage Pipes and direction and extent of slope on the roof. Drainage slope should

not be flatter than 1 in 80 and should preferably be 1 in 40. There should be no

undulations in the roof surface, which may result in accumulation of rain water. At

the time of construction, the roof levels should be personally recorded by the

Inspector of Works and 100% check exercised by the Assistant Engineer. Extra care

is necessary for construction of goals, coping and joints.

iv) At the extension joints in buildings, water proofing has to be strengthened by inserting

a PVC Or a copper plate to prevent water from seeping. These joints should also be

plugged by a good sealant. Polysulphide based flexible sealants have good adhesion

to concrete surfaces and can be compressed or stretched up to 50% of the width of the

joints and are good material for sealing of expansion joints. Depth of the expansion

joints above the copper/PVC plate should normally be kept half of the joint width and

should not exceed 20 mm.

v) Special precautions should be taken for sealing of area around the water spouts to make

them water proof.

CHEPTER:- 9 WATER PROOFING

9.1:- What is Water Proofing?

Ø Waterproof or water-resistant:- describes objects relatively unaffected

by water or resisting the ingress of water under specified conditions. Such items may be

used in wet environments or under water to specified depths.

Ø In construction, a building or structure is waterproofed with the use of membranes and

coatings to protect contents underneath or within as well as protecting structural integrity.

Ø The waterproofing of the building envelope in construction specifications is listed under

'07 - Thermal and Moisture Protection' within Master Format 2004, by the Construction

Specifications Institute, and includes roofing material as well as waterproofing materials.

Ø Waterproofing is used in reference to building structures (basements, decks, wet areas,

etc.)

Ø Waterproofing should not be confused with roofing, as roofing cannot necessarily

withstand hydrostatic head, and waterproofing can.

9.2: CONCRETE WATER PROOFIN CRYSTALIZATION

These products comprise mineral based hydraulically setting products, which when

applied to concrete as a cementations slurry react with concrete to form a crystalline structure

deep within the capillary and pore structures, blocking voids and producing a water proofing

effect. Cement and sand used in the product are used as a carrying agent for the chemicals.

The active components in slurry react with the by – products of cement hydrations and give

rise to insoluble crystals. The system becomes permanent, integral part of the concrete itself..

There is no other preparation of concrete needed beyond cleaning the surface. The product

comes in different names and the products available and their manufacturers are given at

annexure.

This treatment may be useful for dampness due to capillary action of poorly executed plinth

damp course. For better results however downwardly inclined holes are to be bored in the

masonry where the “Semitist VK” of MC Biochemical can be grouted. This will diffuse into the

masonry and give plinth protection from dampness.

Sketches showing some different types of water proofing arrangements for existing and

new constructions are enclosed at annexure 1-5.

Addresses of some of the manufacturers of various water proofing materials are also given at

Annexure 7.

9.3:- Water Proofing Compound

• Use:-

It is used for water proofing of any surface from which water is leaking or as pre

safety measure.

• Contents:-

It is composed of mainly two things one is the liquid form compound and a sheet of

finely fibers of plastic.

• How to use:-

• First of clean up the surface where proofing is to be applied.

• Apply a single layer of the mixture.

• Spread the fiber sheet over the entire area.

• Now again apply another layer of the mixture.

• And let it to dry.

• Costing:-

• Compound: 60-70rs per liter

• Fiber sheet: 60rs for 1.2*1 sq.

PAINY BARS

Isolation joints have one very simple purpose—they completely isolate the slab from something

else. That something else can be a wall or a column or a drain pipe. Here are a few things to

consider with isolation joints:

Even wooden columns should be isolated from the slab.

Walls and columns, which are on their own footings that are deeper than the slab

subgrade, are not going to move the same way a slab does as it shrinks or expands from

drying or temperature changes or as the subgrade compresses a little.

Very long unjointed sections can expand enough from the hot sun to cause blowups, but

this is rare.

If slabs are connected to walls or columns or pipes, as they contract or settle there will be

restraint, which usually cracks the slab—although it could also damage pipes (standpipes

or floor drains).

Expansion joints are virtually never needed with interior slabs, because the concrete

doesn't expand that much—it never gets that hot.

Expansion joints in concrete pavement are also seldom needed, since the contraction

joints open enough (from drying shrinkage) to account for temperature expansion. The

exception might be where a pavement or parking lot are next to a bridge or building—

then we simply use a slightly wider isolation joint (maybe ¾ inch instead of ½ inch).

Blowups, from expansion of concrete due to hot weather and sun, are more commonly

caused by contraction joints that are not sealed and that then fill up with noncompressible

materials (rocks, dirt). They can also be due to very long unjointed sections.

Isolation joints are formed by placing preformed joint material next to the column or wall

or standpipe prior to pouring the slab. Isolation joint material is typically asphalt-

impregnated fiberboard, although plastic, cork, rubber, and neoprene are also available.

Isolation joint material should go all the way through the slab, starting at the subbase, but

should not extend above the top.

For a cleaner looking isolation joint, the top part of the preformed filler can be cut off and

the space filled with elastomeric sealant. Some proprietary joints come with removable

caps to form this sealant reservoir.

Joint materials range from inexpensive asphalt-impregnated fiberboard to cork to closed

cell neoprene. Cork can expand and contract with the joint, does not extrude, and seals

out water. Scott Whitelam with APS Cork says that the required performance is what

determines the choice of joint materials. How much motion is expected, exposure to salts

or chemicals, and the value of the structure would all come into play—and of course the

cost.

At columns, contraction joints should approach from all four directions ending at the isolation

joint, which should have a circular or a diamond shaped configuration around the column. For an

I-beam type steel column, a pinwheel configuration can work. Always place the slab concrete

first and do not install the isolation joint material and fill around the column until the column is

carrying its full dead load.

Polyethylene foam isolation joint material comes in various colors. C2 Products