Flat Roof Torch-On Waterproofing in Fourways & Johannesburg

Flat roofs behave differently from every other roof type. A pitched roof sheds water by itself. A flat roof relies entirely on its slope and its waterproofing layers, so a small mistake in gradient or detailing shows up as ponding, cracks or seepage within months.

That is why we do one thing on flat roofs: torch-on. It is the system we know best, and the one we trust on a Johannesburg flat roof.

How We Waterproof a Flat Roof

Every flat roof we torch-on follows the same sequence. The order matters as much as the membrane.

Inspect and moisture test

We inspect the whole roof, mark where water is ponding, check the condition of the existing layers and test for moisture beneath the surface. This tells us whether the roof needs a repair or a rebuild before a quote is written.

Strip what has failed

If the old membrane has delaminated, blistered or lost adhesion, it comes off. If it is still sound and compatible, we can build on it. We decide case by case, so you only pay for the work the roof actually needs.

Correct the slope

Water has to leave the roof. Where the fall is wrong, we re-profile the surface so it drains toward the outlets. A torch-on membrane cannot fix a roof that holds water, so this step comes before the membrane goes on.

Prime and lay the torch-on membrane

The surface is primed for adhesion, then the torch-on membrane is heat-fused in layers to form one continuous, flexible waterproof skin that moves with the roof instead of fighting it.

Detail and seal every junction

Parapet bases, wall junctions, outlets, vents and penetrations are where most leaks begin. Each one is detailed and sealed individually, and every seam and edge is checked before we move on.

Finish with a silver UV-reflective coat

The finished membrane is coated with a silver reflective finish that protects it from UV and helps reduce the heat the roof absorbs.

When to Build Over and When to Rebuild

Many clients ask whether a roof needs a full rebuild or just a repair. It depends on how the previous system was applied and how much water has already got in. If the existing membrane still has integrity, we can build the torch-on system over it. If the old layers have delaminated, we strip them, re-profile the slope and rebuild from the base up. This case-by-case approach saves unnecessary cost while keeping the result reliable.

Flat Roofs We Torch-On

We torch-on concrete slabs, parapet roofs, extensions and balconies, on homes, estates, and commercial and industrial buildings. Different buildings need different detailing. Parapet walls on residential roofs trap water at the edges, while commercial roofs carry foot traffic and plant such as HVAC units, so we adjust reinforcement layers and drainage detailing to suit.

Results That Prove Performance

We have waterproofed everything from small residential slabs to 2,000 m² industrial roofs across Johannesburg. Clients often call us back for new projects, not repeat repairs, because the first job held up through multiple rainy seasons.

Preventing Future Flat Roof Leaks

A short visual check before each rainy season catches small problems early. Look for lifted edges, cracks near parapets and standing water that lasts more than 24 hours. For commercial buildings, a professional inspection every 12 to 18 months is the best insurance against major failures, and we offer these inspections as part of a long-term maintenance plan.

Flat Roof Torch-On FAQ

Why torch-on for a concrete flat roof?

A torch-on membrane is heat-fused into one continuous, flexible layer that handles heat and movement, which is why it suits a concrete flat roof better than thin paint-on coatings.

How can I tell if my flat roof needs re-waterproofing?

Signs include peeling coatings, cracks near drainage points, or damp marks on ceilings. A moisture test can confirm whether water has got in beneath the membrane.

Can you torch-on over my existing membrane?

Sometimes. If the existing membrane is still sound and compatible, we can build the torch-on system over it. If it has delaminated, we strip it first. We confirm which at the inspection.

Do you torch-on around solar panels and rooftop equipment?

Yes. We detail around solar bases, vents and piping with reinforced flashings, so the penetrations do not become weak spots.

Will the finish keep my building cooler?

The silver reflective finish reflects UV, which can reduce roof surface temperatures by several degrees and help keep the building cooler.

Looking at other roof types? See our roof waterproofing services

Service Areas

We provide professional waterproofing and painting services across Fourways, Sandton, Kyalami, Dainfern, Bryanston, and areas within them.