ST : Look Ma, it's raining inside

Aug 21, 2010

home & garden

Look Ma, it's raining inside

It is not only difficult to pinpoint the cause of leakages, but it is also problematic to resolve

By huang huifen

A thunderstorm woke up business manager Ray Ang and his family at 5am two months ago. But it was more than deafening thunderclaps that did it - the booms were followed by the sound of water splashing.

The family got out of their beds and saw rainwater gushing into the room of Mr Ang's father through a hole in the false ceiling of the double-storey terrace house in Bukit Timah. The leak was so bad, it also caused water damage in other rooms on the second floor.

Mr Ang's daughter, Tabitha, 24, says: 'We couldn't sleep after that. With the continuous heavy rain, we were afraid the whole ceiling would collapse.'

As a temporary measure, Mr Ang screwed a wooden plank into the ceiling to cover the 30cm-long hole. He plans to renovate the house soon and redesign its pitched roof, which he thinks is the cause of the problem.

'The unusually high amount of rainfall overflowed the gutter and caused rainwater to seep through the tiles of the roof and the false ceiling to give way,' says the 54-year-old, whose family has lived in the house for 17 years.

Aside from causing flash floods across the island, the recent heavy rainfall has resulted in water leakage in many houses.

Managing director Francis Lee of Lee Construction, which provides waterproofing application and repair services, says his firm has seen double the number of repair jobs related to damage caused by the rain in the last two months. The figure is up from the usual 10 cases a month.

He adds: 'A heavy rainy season is the time when most areas will see leakage, as buildings, with wear and tear over the years, will not have sufficient waterproofing to withstand the rain.'

Another waterproofing company, Mastercoat Services, reports a 20 per cent increase in repair cases in the last three months. Its director Micky Pang says: 'With the continuous rain, many roofs will leak and need to be re-waterproofed. We have seen six cases a month compared to the usual four cases.'

The recent spate of bad weather in Singapore is providing an unforgiving test of waterproofing systems that are old and worn and improperly or poorly installed.

What makes water leakage more of a pain than other construction problems is that it is often difficult to identify the cause of the leak.

Then, once the exact nature of the leak is pinned down, the affected area may need to be hacked to fix the leak.

For Ms J. Yeo, 50, it took several unsuccessful attempts to fix a leak in her toilet, which affected her direct neighbour below, before she decided to refurbish it.

The decision caused the director of an investment company thousands of dollars and three weeks of inconvenience to the tenants of her Balmoral Road property.

After a ponding test - where an area is flooded with water for about 48 hours to check for seepage - the leak was suspected to be caused by the wear and tear of the old waterproofing membrane.

To repair it, the contractors said the bathroom's floor tiles and concrete had to be hacked and they had to apply a layer of flexible cementitious-based membrane - or a cement-based liquid-applied waterproofing material - to the surface. The leaking has since stopped.

'It was so inconvenient. To make sure this does not happen again, I renovated the affected bathroom in the master bedroom and the common bathroom,' says Ms Yeo.

Depending on the scale of the problem and where the leakage occurs, a typical waterproofing repair work may take days to weeks to complete, and cost a few hundred dollars to $100,000.

Waterproofing is a construction process where layers of chemical membranes such as cementitious, acrylic or polyurethane-based membrane are applied over the surface before the cement is laid.

When waterproofing fails, the affected areas are usually fixed with polyurethane grouting - a hole is drilled into a wall, floor or ceiling and the chemicals are injected into it to seal up the cracks. For more serious cases, the entire area may need to be hacked and re-waterproofed.

For leaking roofs, re-waterproofing and re-tiling should solve the problem, at a cost ranging from $1,000 to $100,000.

Obviously, the key to avoiding such hassles is to have good waterproofing workmanship done right at the construction stage. But that is easier said than done.

In an industry where fast is good and cheap is gold, waterproofing specialists say they are not given enough time to cure the material and conduct watertightness tests to ensure a foolproof system before the next group of workers starts work.

A waterproofing process takes a few days, including time taken to cure and strengthen the membrane as well as to conduct a 48-hour ponding test.

And even after all this is done correctly, during the course of the rest of the construction, the waterproofing might be damaged by other workers and this might not be reported to the main contractor.

'As a result, waterproofing specialists are not alerted to touch up the openings in the waterproofing membrane,' says Ms Teresa Lim of Quicseal Construction Chemicals, a manufacturer and supplier of waterproofing materials.

There is another possible problem.

Mr Lee of Lee Construction says: 'Nowadays, as long as you have money, you can set up a company and get the general workers to do waterproofing. But waterproofing is a high-skilled work which requires training.'

As such, the Waterproofing Trades Association Singapore, which was set up in 2008 to promote exchange of information among the industry players, will be releasing two guidebooks on material selection and instructions on waterproofing application methods.

Currently, similar guidelines are available under the National Productivity and Quality Specifications project by the Building and Construction Authority, Singapore Institute of Architects, Institution of Engineers Singapore and Association of Consulting Engineers Singapore.

The guidebooks will be 'more specific and a practical guide to waterproofing', says Mr Alfred Lim, president of the association.

For HDB flats, HDB's website provides renovation guidelines on waterproofing requirements. Home owners also cannot replace the original waterproofed toilet floor and wall tiles for three years after getting the keys to a new flat.

Despite these guidelines, about 64 of the 72 disputes between neighbours brought before the Strata Titles Boards last year involved leaks. Properties with strata titles are private residential apartments such as condominiums and mixed development with commercial and residential in one building.

In 2005, the board made owners of upper-floor units responsible for water leaks as a result of wear and tear through their floors. Under the HDB Lease, both residents of the upper- and lower-floor units share the responsibility.

No matter what guidelines are in place and adhered to, the sobering truth, experts say, is that all buildings will face leakage at some point in time. Only the degree of leakage differs, says Mr Lee.

Mr Ashvin Kumar, president of the Singapore Institute of Architects, adds: 'When there are freak weather conditions, like a once-in-50-years severe storm, no building can be detailed sufficiently or appropriately to address the ramifications of such havoc.'

hfhuang@sph.com.sg


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STOP THE FLOW

Signs of water leakage

· Flaking on the ceiling

· Water dripping from the ceiling

· White crystallisation appearing near the exposed pipe areas

· Dampness on walls, ceilings and floor slabs

What to do

· Engage a trusted contractor. The Singapore Concrete Institute, a non-profit organisation, has a list of accredited waterproofing firms on its website (www.scinst.org.sg).

· The Building and Construction Authority (BCA) also has a list of registered waterproofing contractors on its website (www.bca.gov.sg).

In addition, it has a Good Industry Practices Guide Book on its website for industry players and home owners to find out more about the standards of waterproofing internal wet areas and external walls.

Sources: Quicseal Construction Chemicals, Bestcoat Contract Services and Singapore Institute of Architects


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'It was so inconvenient. To make sure this does not happen again, I renovated the affected bathroom in the master bedroom and the common bathroom'

Ms J. Yeo, whose toilet in her condo apartment leaked and affected her neighbour



After a 30cm hole in the ceiling (above) let rainwater gush into a room in Mr Ray Ang?s house, the business manager boarded it up with a wooden plank. -- ST PHOTOS: AIDAH RAUF