Kumasi anchors Ghana’s timber and furniture trade. The Kaase–Asokwa stretch has run the region’s wood processing for sixty years. The city gets around 1,400 mm of rain a year, and humidity climbs toward 82% in August. A local wood-processing operator needed a single-span production hall built for that climate. Xinguangzheng designed and delivered it — one of several Ghana steel factory projects we have shipped into the region.
The challenge
A wood-processing operator in the Kaase district needed 5,000 m² of clear floor under one roof. The space had to run milling lines, kiln-dried lumber racks, and finished-component storage with no columns in the way. The brief fixed the footprint at 100 m by 50 m, with a 7 m eaves height to clear stacked timber and overhead handling.
The harder problem was moisture, not floor area. Humidity here sits above 75% for most of the year, and rainfall peaks near June. Steel in this climate corrodes faster than dry-climate catalogue figures suggest. Condensation also forms easily on the underside of cold roof sheeting.
The site sits about 260 km inland from the coast. All delivered steel comes through the port of Tema and up the N6 corridor by road. Kumasi also has a documented flood history — the 2021 Atasemanso event displaced several hundred residents. So the brief was not for a generic warehouse. It was for a humidity-resistant, flood-aware steel production hall serving timber processing in Kumasi.
What we built
A single-span portal frame of 100 m length, 50 m clear width, and 7 m eaves height encloses the full 5,000 m² floor with no internal columns. We prefabricated the steel in Qingdao, China, shipped it by sea to the port of Tema, then trucked it inland to the Kaase site for assembly.
We chose a single-span portal frame over a multi-bay layout for one reason: timber handling needs uninterrupted floor. Forklifts and drying racks lose time around columns. The 50 m span sets the rafter depth and haunch sizing. We designed the members for combined dead, wind, and suspended-services load, added lateral bracing in the end bays, and held deflection tight enough to protect cladding lines and gutters through the wet season. It uses the same steel workshop building frame logic we apply across humid-climate sites.
Here is how we addressed the five core technical requirements:
- Corrosion protection — Hot-dip galvanizing to ISO 1461 on secondary steel, plus a three-coat epoxy system on the primary frames, specified against inland high-humidity industrial exposure under ISO 12944. We weighed galvanizing against paint for steel and ran both, because each does a different job here.
- Flood resilience — A raised reinforced plinth sets the finished floor above local grade. Perimeter drainage moves surface water away from the building line during heavy rain.
- Roof ventilation — A continuous ridge vent works with sidewall louvres to push hot, moist air out. This cuts condensation on the underside of the sheeting. The full approach follows our standard for how to ventilate a metal building in a wet climate.
- Anti-condensation lining — Anti-drip insulated roof panels hold moisture against the panel. It does not fall onto finished timber below during temperature swings.
- Crane provision — Column brackets are sized for a future 5-tonne overhead crane, with wheel-load and longitudinal-brake allowances. Lifting can be added later without re-engineering the frame.
Assembly ran alongside a local Kumasi erection crew. One container of purlins arrived with transit damage to several end laps after the inland road leg. Rather than wait on a re-ship, we cut and re-formed the affected sections on-site from spare stock carried in the same consignment. This held the erection sequence to schedule. We planned the sea freight through Tema and the N6 haul into the program from the start.
Design basis used for the Kumasi hall
- Building code: Ghana Building Code GS 1207:2018
- Structural system: single-span portal frame, clear 50 m span
- Design checks: wind load, roof dead load, suspended-services load, frame deflection, cladding-line tolerance
- Corrosion strategy: coating system selected against high-humidity inland industrial exposure (ISO 12944 / ISO 1461)
- Flood strategy: raised plinth set above local grade, with perimeter surface-water drainage
Key metrics
- 5,000 m² — single-span clear floor
- 260 km — inland haul from port of Tema
- 5-tonne — future crane provision built into frame
Technical specification
| Parameter | Figure | Function |
|---|---|---|
| Length | 100 m | Runs the full production-to-storage line |
| Width (clear span) | 50 m | Column-free floor for forklift and rack routes |
| Eaves height | 7 m | Clears stacked timber and handling |
| Floor area | 5,000 m² | One uninterrupted production hall |
| Frame type | Single-span portal | No internal columns break the flow |
| Primary coating | 3-coat epoxy (ISO 12944) | Resists 75%+ year-round humidity |
| Secondary steel | Hot-dip galvanized (ISO 1461) | Protects purlins and girts from moisture |
| Roof panel | Anti-drip insulated | Holds condensation away from stock |
| Ventilation | Ridge vent + louvres | Clears hot, humid internal air |
| Floor plinth | Raised reinforced slab | Sets the floor above local grade |
| Drainage | Perimeter surface-water channel | Moves rain runoff off the building line |
| Crane allowance | 5-tonne provision | Future overhead lifting, no re-build |
| Design code | GS 1207:2018 | Ghana national building code |
Results
We handed the building over on 13 February 2026, on schedule and inside Kumasi’s dry season. Rainfall then sits near 22 mm across only a handful of days. The frame went up in dry conditions, which kept the coating cure and the slab pour clean through erection.
The raised plinth, perimeter drainage and full coating system are in place ahead of the wet season. Early dry-season performance matches the GS 1207:2018 design intent. We will confirm the flood plinth and condensation control after the first heavy rains from May onward, when June rainfall climbs toward its annual peak.
We designed the three-coat epoxy and galvanized secondary steel for long service before the first major recoat, given a regular inspection regime and this humidity exposure. We specified the ridge vent and anti-drip lining together to reduce condensation-related stock-loss risk through the humid months. Building a timber factory in Kumasi’s wet tropics reshapes the whole brief. The coating spec, the ventilation logic, and the plinth height all answer this climate directly — not a generic warehouse template.
Xinguangzheng designs and prefabricates steel production halls for timber processors and manufacturers building in humid or flood-prone climates. We deliver the frame, coating concept, ventilation approach, and flood detailing as one package. This Kumasi hall is one of our industrial buildings for sale built to a site-specific brief. If you have a footprint and a production requirement, we can return a preliminary structural layout and an all-in delivered cost estimate within three to four working days.
“What stood out first was how dry it stayed inside during handover — no drip off the roof even on the warmer afternoons. It’s early days, and we’ll know more once the rains come in May. But the floor sitting up off the ground already gives us confidence. The team worked well with our local crew.”— Kwabena Osei, Operations Manager
