JOIN USWater leakage or more categorically moisture ingress in buildings results in damp, uncomfortable internal environments; deterioration of internal finishes (including mould growth); unsightly damp areas on wall and ceiling surfaces and increased concentrations of harmful pollutants affecting the occupant’s health.
The exclusion of moisture from buildings is therefore not only desirable, but is of utmost concern to the residents of buildings. High-wind speeds experienced by high-rise buildings also increase the likelihood of water seepage.
“Water tightness of external walls is usually achieved by providing adequate wall thickness, proper designing at construction joints and surface rendering and finishes, which serve as a barrier against water ingress.
But normally no attention is paid towards critical areas like separation gaps, honeycomb areas, damp proof courses at plinth level and so on. This results in serious leakages through external walls and damage to expensive internal paints and finishing,” says A K Chatterjee, Director, Dr. Fixit Institute, Pidilite Industries.
Getting it right
As a rule of thumb, the costs of waterproofing averages less than five per cent of total construction cost.
More than 80 per cent of the damages in construction are directly or indirectly linked to problems caused by moisture. This makes quality water-proofing a must for every home.
“All preparations vary for new construction and repair work. Generally, our technical team visits the site and with thorough inspection and analysis, we offer the customer the right solution depending upon the criticality of the structure.
“Whether the matter is restoration of a heritage building, reinstalling failed horizontal barriers in masonry, restoration of wet basements or water-proofing of roofs and facades, all of these require a thorough knowledge of construction material, physical conditions, ground water levels, climate and many others are numerous factors, affecting the requirement of water-proofing. Almost all construction material is moisture absorptive.
“To protect these adequately, a transparent or coloured protective coating is necessary. While renovating bath rooms and also kitchens, one should not forget the water-proofing.
“You protect the surfaces against unwanted moisture ingressions and leaks into adjoining rooms. It has been known for years that mould in living rooms is a health hazard. Mould and bacterial growths are the reasons for many cases of allergies and breathing problems,” says Ewart Lazarus, Executive Director, Chowgule Construction Technologies Pvt. Ltd.
Though roof water-proofing done by conventional water-proofing systems like bitumen, brickbat coba and mud phuska proved to be successful, they have their inherent problems like short life and long installation procedures causing problems in time-bound projects.
Climatic changes and weathering effects are one of the major issues for the non-acceptability of these techniques. Raghu Balan, Executive Vice President – QST (Quality, Safety and Technology), Sobha Developers says, “we have different water-proofing systems applied for different conditions.
For example, we do undertile brush-on application of synthetic rubber based elastomeric polymer waterproof membrane in toilets, balcony, utilities and slopped roofs. For terraces and podiums, Sobha uses APP modified bitumen membrane.
Different methods are being put into practice in different places, based on different exposure conditions. An APP membrane is used in situation where human traffic is high during construction and for less traffic areas/ confined spaces brush-on method is used."
Chowgules offer a wide range of products and effective systems which have ensured safe water-proofing for decades – all the way from the basement to the roof. Major areas which need eye-to-detail when it comes to waterproofing are external basements, which should have an expected life time similar to that of the house itself and internal basement, (exactly as with the walls, the floor also requires waterproofing against pressurised water.
Walls in new construction must be protected against rising dampness; construction joints between two concrete slabs need to be safely sealed using injection grouting technique.
Concrete needs to be protected against weathering; the protection is undertaken using colourless impregnation systems. For long term, expansion and construction joints need to be sealed. Critical wet room areas like bath room, toilets and kitchen sunk areas need to be waterproofed simply and efficiently against moisture absorption and leakages.
For exposed roofs, one needs a UV-resistant coating suitable for new construction as well as a preventive measurement for existing buildings.
Potable (drinking) water tanks and water treatment installations have especially high requirements for the water-proofing systems used in terms of hygiene and safety.
Damp walls are a nightmare in the monsoon. The easiest way to maintain dryness and prevent leakages is by tiling up your wall. “Tiles are simple to maintain at a negligent cost and add an attractive effect to the room. One of the greatest properties of tiles is that they are non-porous which means that their surfaces are completely sealed.
“A wall however has minute openings which enable water to leak in. Having non-porous surfaces also means that it does not absorb oil and other likely stain-causing elements.
The non-porous nature of wall tiles means they do not swell or otherwise become disturbed during or after exposure to moisture, such as from the steam of a shower or the splashing of water in a kitchen sink,” says Alok Goel, CEO of Nitco Limited.
Challenges
The main requirement is that the inherent quality of concrete should be good, proper slope has to be provided (Example: Toilet – 1:60, Balcony – 1:80, Podium – 1:80 , Terrace – 1:100). Also adequate drainage points have to be provided. The whole idea is to drain off the water quickly, through the shortest route.
The precise product has to be adopted with proper application methodology. Required surface preparation has to be ensured. Proper protection needs to be ensured during and after application. Also the whole system needs to be looked into holistically and treated individually.
Generally all products of reputed companies are reliable. The key to success for a effective waterproofing lies in the workmanship and its protection thereafter.
Application of water-proofing materials is unique as per materials and manufacturers’ specifications. When considering the millions of square feet of water-proofing systems installed and miles of sealant involved in building envelopes, it can be estimated that only one per cent of envelope failure and resulting leakage is actually attributable to materials or systems failing.
The reasons for failures include human installation errors, the wrong system being specified for in-place service requirements (example: thermal movement encountered exceeds the material’s capability), the wrong or no primer being used, inadequate preparatory work, incompatible materials being transitioned together, and insufficient – or in certain cases such as sealants, too much – material being applied.
Fundamentally, waterproofing failures are attributable mostly for improper preparation of base surface before installing the system – hence it’s important to keep a watch while installation of a system is done.
For example, cleaning of loose particles, oil, etc followed by checking moisture content before application of a sheet membrane or preparing a surface saturated dry (SSD) substrate before application of a polymer modified cementitious coating are the prime requirements to get the desired results, according to A K Chatterjee of Pidilite.
Waterproofing systems last five years in case of repair to even 20 years, in case of new construction. Depending upon the type of water-proofing solution used for respective areas i.e basements, roofs, terraces, toilets, kitchen sunken areas, podiums, etc, the cost generally varies between Rs 160 per sq.mt. and Rs 1,600 per sq.mt.