Rain is great for your garden, but can lead to some problems in a home.
When it comes down the rain is always good for the garden – but not always so good for the house. Water seeping into parapet walls and balcony floors that aren’t properly waterproofed can lead to unsightly stains and problems, such as streaking, peeling paint or nasty fungal growths.
Dealing with the problem takes some time and effort, but with the right products and a little bit of elbow grease, it can be sorted out for good.
Dawid du Plessis, technical services manager at Prominent Paints, says unsealed parapets should be treated with a fibre-reinforced, water-based product like Fibre Seal. As with any coating, the finish is only as good as the undercoat, so be sure to first remove loose paint, fungal growth or dust. Priming should then be done with an appropriate primer, such as Damp Cure, which is moisture-tolerant.
Fibre Seal should be applied with an oval brush, rather than a roller. A roller will result in too thin a coat and potentially leave air bubbles on textured plaster. A brush ensures that the sealant is worked into all areas of the parapet.
The spreading rate for Fibre Seal is one square metre a litre; two coats should be applied, with 24 hours allowed between coats for curing. The second coat should be applied perpendicular to the first. This enables the fibres to create a lattice and improves the waterproofing capability.
When coating the vertical surface of a parapet it is important to overlap the coating by approximately 10cm onto the horizontal areas. This ensures complete protection and prevents later problems with bubbling and cracking on these surfaces.
When choosing a topcoat, du Plessis says it is important to remember that a fibre reinforced system is more flexible than raw plaster. The correct topcoat must be used to prevent cracking; a quality top coat with a seven year lifespan is recommended. In addition, sheen or textured coatings tend to be more compatible than a matt finish.
Homeowners with face brick parapets that require waterproofing are unlikely to paint over the natural finish. In such instances, du Plessis says Surface Sealer is an appropriate choice. A silicon-based water repellent, it will permanently waterproof stone or face brick without any colour enhancement.
He suggests a liberal application of Progold Fungal Wash before sealing the bricks to eliminate fungal growth.
“Using a brush, apply Fungal Wash at a ratio of a litre for every four square metres, waiting eight hours for curing. Be sure to confirm that it is completely dry before applying Surface Sealer – otherwise you will simply trap in the damp.”
When it comes to waterproofing balconies, du Plessis says the task is more complicated.
“The biggest problems with balconies are slope, lack of drainage, or drainage holes being incorrectly placed. Many balconies are tiled and applying Damp Cure and Fibre Seal before laying the tiles can certainly help, though you should ensure that the adhesive and grout used are also water resistant.”
Because there are so many factors that can affect a balcony, there is no generic solution, he says.
“The best option is to contact the Prominent Paints customer care line. You will receive a site visit and professional advice, essential to waterproofing a balcony successfully.”
As a final word of advice, du Plessis stresses that when building or painting, you should never neglect waterproofing.
“The finish tends to be left to last, and often budget constraints mean it isn’t done properly. Remember that where waterproofing is concerned, prevention is far better than cure. Going for the cheap option at the start will end up costing you far more in the long run,” he says.
