Experts can keep the house dry in winter
Golden rules for preventing leaks
UNQUALIFIED waterproofing contractors and inappropriate materials are responsible for most building leaks, say the experts.
Addressing a trustees’ meeting organised by the National Association of Managing Agents (Nama members are responsible for the running of sectional title schemes) at the Cape Town International Convention Centre, Peter Jack, managing director of the multi-disciplinary contractor Indawo, said his company’s waterproofing teams were at this time of year regularly called out when it rained.
“In May, June, July and August we find that waterproofing repairs increase by some 300 percent,” he said.
“Most of these repair tasks should never have been necessary and could have been avoided. Most often the original installation and specification of the waterproofing was not handled by qualified people, or the maintenance had often not been carried out as specified by the manufacturer.
“If the original installation is done inefficiently or with inappropriate materials it will delaminate, crack or lose adhesion very quickly.”
Three main types of material were used in waterproofing. These were bitumen, which was particularly suitable for flat roofs; acrylic compounds, which were ideal for parapets and walls; and “cementitious” coatings, which had many uses but were particularly known for their ability to give a good surface on walkways. Some of these coatings incorporated additional layers such as polyester cloth, but almost all of them were tried and tested and, if properly applied, would perform well.
Once in place the waterproofing treatments had to be maintained every two to five years, depending on which material had been selected. If proper maintenance wasn’t carried out, they would start to leak.
“If water penetrates into a steel reinforced concrete structure it will rapidly corrode the steel and cause spalling, or cracking of the structure, which will in time make the whole building completely unsound.
“In many cases, however, the water will not penetrate through to the steel but it will come up under painted surfaces. No matter how well these coatings have been applied and how good the paints, these will eventually peel and flake as a result of the subsequent underlying moisture content not dealt with in the waterproofing specification or application.”
Jack said property owners could ensure that the original installation and the later maintenance of the waterproofing were done professionally if they used members of the Waterproofing and Roofing Association Cape, whose members all also belonged to the Master Builders’ Association.
“Association members are all tried and tested waterproofing practitioners with skills not possessed by the average building contractor. In almost all cases they will submit full specifications as well as guaranteeing the work they do. Also, if there are any complaints against them, the association’s committee will do all it can to put matters right. For all these reasons it definitely pays to use the association’s waterproofing contractors”
A large recent contract handled by Indawo was a seven-storey block of flats, Lynwood Gardens in Kenilworth, where, in addition to waterproofing, concrete spalling repairs of the type described above were carried out over a period of 24 weeks and V-joints inserted in the brickwork. Indawo is now busy with the parking deck for Ostende flats in Sea Point, which was originally waterproofed 24 years ago.
“Modern waterproofing systems are efficient if applied and maintained correctly. Regrettably, there are still a great many inefficient, unqualified people doing this work,” said Jack.
Call Peter Jack on 021 941 5000 or e-mail firstname.lastname@example.org.
LAYING IT ON: A 4mm ‘torch on’ bitumen waterproofing product being applied by one of Indawo’s qualified teams.