Waterproofing is only as good as the diagnosis behind it. A damp patch on a ceiling may be a flat roof leak, a failed flashing, a blocked box gutter, a cracked parapet, condensation or rising damp, and each needs a different fix. A good waterproofing contractor finds the source first, then chooses a torch-on or liquid membrane system, gets the falls right so water reaches the drains, and gives you a written guarantee. Describe the problem and the area, and waterproofing companies near you quote you directly. Asking is free, with no obligation.
Find the source first
Paint does not cure damp, and neither does a membrane on the wrong spot. Leaks from above show as stains on ceilings and the tops of walls, worse after rain. Rising damp shows as a tide mark low on the wall, flaking paint and efflorescence near the floor, all year. Condensation shows as mould in corners of cold, steamy rooms. Ask the contractor to say what they think the cause is, in writing, before they price the fix.
Torch-on or liquid membrane
Roof waterproofing on flat roofs is usually a membrane system:
- Torch-on: bitumen membrane rolls, heated with a gas torch onto a primed surface, laps sealed. Strong and widely used on flat concrete roofs.
- Liquid systems: a liquid waterproofing coating applied in layers with a fibre membrane bedded in, often used on parapets, box gutters, small roofs and awkward details.
Either way, the top needs protection from the sun, often a reflective coating or paint. See waterproofing membranes and waterproof paint.
Falls, drains and flashings
Water standing on a flat roof for days attacks any membrane. A contractor should check the falls to the outlets, clear the drains and box gutters, and build up low spots with a screed if needed. Flashings where the roof meets a wall or parapet are where most leaks start, so they must be detailed carefully.
Waterproofing prices and quotes
Torch-on waterproofing is about R300 to R500 per m², and guides put other systems at about R250 to R900 per m². Stripping an old membrane, screeding falls and many details add to it. Ask each quote to list the system, the layers, the prep and what guarantee is given, in writing.
What to include in your request
- Where the water shows: ceiling, wall, floor
- Roof type and rough area in m²
- Existing membrane, and its age if known
- Parapets, drains and box gutters involved
- Photos of stains and the roof surface
Waterproofing for different clients
- Homeowners: a leaking flat roof, balcony or parapet traced and sealed with a membrane system
- Landlords and sellers: a recurring leak fixed properly before ceilings and tenants' belongings get damaged
- Body corporates and estates: flat roofs and parapets across a complex resealed on one contract with a guarantee
- Shops, offices and restaurants: office and shop flat roofs and box gutters resealed before the rains
- Factories, farms and mines: factory box gutters, concrete roof slabs and loading dock canopies waterproofed
- Builders and developers: new flat roofs, balconies and planters waterproofed before finishes go on
- Schools, churches and public buildings: school, church and clinic flat roofs traced for leaks and resealed over the holidays
- Painters and contractors: waterproofing teams quoting torch-on and liquid membrane jobs in their area
Frequently asked questions
What is the torch-on waterproofing price per m²?
Is waterproofing paint enough for a flat roof?
Can waterproofing fix rising damp?
Do you do the waterproofing yourselves?
Waterproofing by province and city
- Johannesburg
- Pretoria
- Centurion
- Midrand
- Sandton
- Randburg
- Roodepoort
- Krugersdorp
- Randfontein
- Germiston
- Boksburg
- Benoni
- Kempton Park
- Alberton
- Vanderbijlpark
- Vereeniging
- Durban
- Pinetown
- Pietermaritzburg
- Richards Bay
- Newcastle
- Ladysmith
- Gqeberha (Port Elizabeth)
- East London
- Kariega (Uitenhage)
- Mthatha
- Cape Town
- Bellville
- Paarl
- Stellenbosch
- George
- Worcester
- eMalahleni (Witbank)
- Middelburg
- Secunda
- Mbombela (Nelspruit)
- Rustenburg
- Brits
- Klerksdorp
- Potchefstroom
- Mahikeng
- Polokwane
- Tzaneen
- Kimberley
- Upington
- Bloemfontein
- Welkom
- Sasolburg