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Watertight Solutions

Roxzanne van Eyk Business Day: 27 May 2005

Strategic waterproofing in and around your home will increase the value of your property and limit inconveniences that may arise from unsightly damp problems, writes Roxzanne van Eyk.
Damp Proofing

Plaster and paint spalling from below the damp proof course of a house.This is a typical example of damp proofing gone wrong from a client that approached Baobab Consulting for help

Picture: Baobab Consultants

When water leaks into a building, not only is it very unpleasant or even a heath risk to the occupants, but it weakens the structure. This can happen not only from leaking roofs and unsealed balconies, but also from rising damp. There are many companies that specialise in the waterproofing sector and will be able to provide you with effective solutions to ensure that your home will remain damp-free.

As most home owners are not familiar with the specifics of waterproofing, it may be to the home owner's detriment to hire anyone that is not an absolute professional.

"Ideally for a job well done, an expert that is affiliated with the Waterproofing Federation of South Africa and the Master Builders Association should be contacted", say the experts from Multi-Dex insulated waterproofing.

Some waterproofing services that are offered may not comply with good building practice. Sometimes unnecessary work will be undertaken only to increase the price quoted. Peter Allsopp, owner of Baobab Consulting, a building troubleshooting service says that there is no point in only waterproofing the walls between the finished ground level and the Damp Proof Course (DCP) level if one can prevent the damp from occurring at source. "It is much better to solve the root cause of the problem than simply to make a temporary decorative repair".

This is particularly so when dealing with flat roofs. "We see an awful lot of rubbish applied to flat roof, which at best provide a fix for a few months only" say Allsopp.

Some things to look at when waterproofing your home, include the roof, gutters, balconies, parapet walls, the top of boundary walls and even inside showers. On the roof one should take time to seal broken tiles or around screws and flashings. Unsealed parapet walls and balcony floors allow water to pool after a storm, which will then seep into the concrete or plaster, which leads to peeling paint and unsightly fungal growth either on the walls or ceiling below. Waterproofing systems need be applied to porous grouts to prevent moisture from penetrating the structure.

"Showers are common areas where rising dam can prove to be a problem and these areas should be sealed as moisture entering the wall on the shower's side, tends to want to escape through the wall on the other side – which can also lead to peeling paint and fungal growth in the adjoining room", says Dawid du Plessis, manager at Barney's Paint Westgate.

If there is insufficient damp coursing before a house is built, it will lead to rising damp. This is often only symptomatically treated with a damp inhibiting coating, but may be necessary to dig down and apply a good waterproofing system to the wall below ground level.

Ideally, the best solution to waterproofing the home would be to strip all the plaster below the DPC and down to the foundation level. From there you will need to apply the necessary waterproofing solution. Problems arise when all the plaster is not removed sufficiently and the problem is only partially repaired.  

"If these issues are not addressed or disclosed to a potential buyer when selling the home, it may be considered a latent defect that you are held responsible for by the buyer", says du Plessis.

Damp can come about for various reasons. A typical example would be from homes that suffer from damp penetration through the ground floor slabs. "High water tables and incorrect soil and foundation preparation often lead to plaster and paint spalling below the DPC level", says Allsopp.

In many cases the treated plaster, which is intended to provide a waterproofing barrier, is sometimes far from being the solution to the problem and a more extensive injection treatment is prescribed.

"It is normal to have some water present below DPC but in order to prevent capillary attraction between below the DPC plaster and above the DPC plaster, it is essential to create what is known as a 'V' cut between the two. In a vast majority of walls, this 'V' cut is no more than the minor indentation created by a rounded tool commonly used to smooth mortar joints in brickwork. There is absolutely no separation between the two skins, which is imperative to prevent rising damp bridging the DPC and entering into the walls of the property" advises Allsopp.

Information sourced from says that to prevent further problems arising or simply to check a potential home's waterproofing capabilities, a full scale investigation is advised so that you are guarded against malpractices and costly errors from unqualified or in experienced contractors.