Torch-on Membrane vs Liquid Waterproofing Membrane — Which Is Better for Ghana?

You’ll see both systems on Ghanaian roofs. Both are called “waterproofing.” Both cost real money. But they are fundamentally different products — different chemistry, different application, different failure modes, different service lives.

This guide gives you the head-to-head comparison so you can pick the right one for your building.

What Each System Actually Is

Torch-on membrane

Bitumen-based waterproofing supplied as a rolled sheet with a heat-sensitive underside. The installer unrolls the sheet on the roof, uses a propane gas torch to melt the underside, and adheres it to the substrate. Seams between sheets are also heat-welded. Also called APP-modified or SBS-modified membrane.

Liquid membrane

A liquid coating applied by roller, brush, or airless spray. Cures on the substrate to form a seamless flexible film. Multiple chemistries available — polyurethane (PU), acrylic-modified, cementitious, and hybrid systems. In Ghana, PU is by far the most common.

Head-to-Head

CRITERION	TORCH-ON	LIQUID (PU)
Application safety	Open flame on roof — fire risk	Cold-applied — no fire risk
Seams	Every sheet is a seam — weak point	Fully seamless
Complex geometry (parapets, penetrations)	Difficult — sheets don’t bend cleanly	Flows into every corner and detail
Heat tolerance	Softens at 55–65 °C — problematic in Ghana	Stable to +80 °C
UV resistance	Needs UV-protective topcoat	UV-stable in one product
Design life	10 – 15 years	15 – 25 years
Cost per m²	GHS 130 – 200	GHS 140 – 350
Weight on structure	Heavier	Very light
Overcoating in 10–15 years	Strip and start again	Recoat directly
Best for	Simple, large flat roofs	Everything else

Why We Almost Never Recommend Torch-on in Ghana

Torch-on membrane has three real problems on Ghanaian roofs:

1. Open flame on an occupied building

Torch-on requires a propane torch running on the roof, right next to timber trusses, insulation, wiring, and other combustibles. Roof fires from torch-on installations happen every year in Ghana. Insurance companies increasingly refuse cover on jobs using open-flame roofing.

2. Seams at every sheet overlap

Every metre of torch-on membrane is a rolled sheet perhaps 1 m wide. That means seams every metre across the roof. Each seam is a heat-welded joint that can fail. Get five years of thermal cycling and one bad seam turns into a leaking roof.

3. Ghanaian heat

Bitumen softens above 55 °C. Concrete roof surface temperatures in Accra midday sun reach 60 °C+. Torch-on membrane in this environment slumps, ages, and cracks faster than in temperate climates.

When Torch-on Might Still Make Sense

We’ll recommend torch-on in a small number of scenarios:

• Large, simple, flat commercial roofs (5,000+ m²) where labour on liquid becomes the dominant cost
• Below-grade applications where the membrane is covered by backfill and UV/heat isn’t a factor
• Very tight budgets on short-hold buildings where 10-year life is acceptable

Even in these cases, we prefer self-adhesive membrane (peel-and-stick) over torch-on because it eliminates the fire risk. Ask for it specifically — same waterproofing performance, safer installation.

What to Ask a Contractor Quoting Torch-on

1. What is the fire-safety plan on my building during installation?
2. Are they insured for fire damage caused during installation?
3. What UV-protective topcoat is being applied on top?
4. What is the warranty on seams specifically?
5. Have they done the same system on other Ghanaian buildings, and can they provide references from clients whose installations are 5+ years old?

Their answers will tell you whether they know what they’re doing.

Get an Honest Recommendation

We install both systems when the job genuinely calls for it. We’ll recommend whichever one is right for your specific building — not whichever one makes us more margin.

• Phone: 0555 548 001 or 0241 737 026
• WhatsApp: Chat with us
• Related: Polyurethane vs Bitumen · Paint vs Coating

Festghana Waterproofing Solution Company Limited (trading as Fest Ghana Limited) provides waterproofing services across Ghana. Workmanship warranty on every job.