Waterproofing BOQ in Ghana — How to Write and Price It (2026)
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Waterproofing BOQ — Structure, Measurement and 2026 Rates
Break waterproofing into separately measured items: preparation, priming, membrane by developed area in m², detail reinforcement in linear metres, upstands in linear metres, and testing as a lump sum. Burying detail work inside the area rate is the most common error and the most common cause of both disputes and failures.
Written for quantity surveyors, project managers and procurement officers pricing waterproofing in Ghana.
Recommended BOQ Structure
| Item | Unit | Notes |
|---|---|---|
| Surface preparation — clean and dust removal | m² | Always separate |
| Removal of failed existing coating | m² | Provisional — extent unknown |
| Crack repair / routing and filling | lin m | Provisional |
| Screed to falls | m² | State minimum fall (1:80) |
| Primer | m² | Specify type |
| Membrane — horizontal | m² | Developed area, state DFT |
| Membrane — vertical / upstands | m² | Separate — higher labour |
| Fleece reinforcement at details | lin m | Never omit |
| Drain outlets and penetrations | no. | Count them |
| Protection layer / screed | m² | If trafficked or buried |
| Flood test | sum | Include — it is your proof |
| Documentation and warranty | sum | Datasheets, DFT records |
The Measurement Trap: Developed Area vs Plan Area
This costs projects more money than anything else on the list.
Waterproofing is measured over the developed surface — the actual area the applicator has to cover — not the plan footprint.
| Surface | Developed area vs plan |
|---|---|
| Flat slab | Same |
| Corrugated sheet | +10–15% |
| Curved / arched roof | ⚠️ +30–55% |
| Box gutter | Measure girth, not width |
| Upstands | Measure separately, both faces if applicable |
Worked example. An arch-span building of 14.4 m clear span and 7 m rise, 29.63 m long, has a plan footprint of 427 m². The developed arc length is 22.2 m, so the internal soffit area is 658 m² — 54% greater. A BOQ measured on plan under-prices that job by more than half.
2026 Indicative Rates — Ghana
| System | Rate / m² | Design life |
|---|---|---|
| Cementitious slurry | GHS 60–90 | 8–12 yrs |
| 2-coat polyurethane | GHS 80–130 | 20 yrs |
| Torch-on bitumen membrane | GHS 150–220 | 12–18 yrs |
| Fleece-reinforced polyurethane | GHS 180–280 | 20 yrs |
Adjustments:
- Stripping failed existing coating: add GHS 15–30 / m²
- Coastal (within 15 km of ocean): add 15–20% for chloride-blocking primer
- Areas under 50 m²: add mobilisation premium
- Areas over 300 m²: 10–20% volume reduction achievable
- Access above 2 storeys: price scaffolding separately
What to Specify, Not Just Measure
A BOQ item that says only "waterproofing membrane" invites the cheapest possible interpretation. State:
- Dry film thickness — the single number that defines the system
- Number of coats and that the second is applied perpendicular to the first
- Substrate moisture limit before application (below 4%)
- Detail reinforcement — where fleece is required and the minimum band width
- Upstand height — minimum 150 mm
- Testing regime — flood test and DFT verification
- Warranty — workmanship period required
Provisional Sums Worth Including
- Removal of failed existing waterproofing — extent rarely known at tender
- Crack routing and repair — measured on exposure
- Localised concrete repair — spalling found during preparation
- Additional drain outlets if falls prove inadequate
We Price BOQs
Fest Ghana Limited provides itemised BOQ pricing for consultants and contractors, with technical datasheets, GSA certification and method statement supplied. 3-year workmanship warranty and 20-year design life on polyurethane systems.
👉 Request BOQ Pricing · 0555 548 001 · festghanalimited@gmail.com