Poultry & Livestock Steel Buildings — Agricultural Structures Built for the Animals, Designed for the Operator

1. Geometry is set by the animals, not the goods. A broiler house is 120-180 m long, 14-18 m wide and only 2.4-3.0 m high at the eave — the geometry that keeps birds at floor level inside the ventilated air envelope. Layer houses run 12-16 m wide with 3.5-4.5 m eaves to fit 3-4 deck cage systems. Pig houses are 12-24 m wide with 2.6-3.2 m eaves for open or tunnel ventilation. The frame's bay spacing (3-6 m) is set by the feeder/nipple-drinker modules and by the manure pit span under slatted floors — not by an economic grid from the structural catalogue. Our standard barn section is a bolted portal frame of welded H-sections (or lattice truss in wide-span designs) with the columns set at 4-8 m centres, carrying roof purlins at 1.2-2.5 m spacing that match the insulation and cladding panels.

2. The environment corrodes the steel as fast as it grows the animals. Ammonia from manure (10-50 ppm in a poorly ventilated house, 2-10 ppm in a well-run one), 60-90% relative humidity, and condensation on the underside of the roof form the most aggressive microclimate in structural engineering. The steel specification is therefore a corrosion strategy: hot-dip galvanizing to ISO 1461 of 65-85 µm on all members and cold-formed purlins, or a 2-coat system of 240 µm total over primers for the exterior. Fasteners are pre-galvanized or stainless (A2/A4) — the single highest-leverage corrosion decision in an agricultural building, because a $0.10 fastener failure every 8 metres of purlin line is how barns fall apart first.

3. Ventilation loads are structural loads. Tunnel ventilation moves 0.05-0.15 m³/s per square metre of floor, through fans mounted in the end gable (typically 12-24 fans of 1.2-1.4 m diameter per 1,000 m² of house). The wind created inside the barn is 3-8 m/s, and the frame must also resist both the external wind load and the negative pressure the tunnel fans create — in positive-pressure and exhaust configurations alike. The gable end where fans mount is effectively a wall of openings, so the end frame is a dedicated wind-resisting system (portal or braced) with the fan plenum integrated; the inlet pad walls at the opposite end are continuous “wet wall” evaporative cooling pads (5060 or 7090 cellulose) whose frames must span 12-18 m without blocking the airflow.

4. Every service is a pre-engineered bracket. Feed lines (two 75 mm auger lines per 5 rows of pans for broilers, or 4 lines per row for layers), nipple drinkers, lighting (dimmed LED by the day), cooling pads, circulation fans, misting lines, manure scrapers and the controller cabinet: each is mounted on a bracket or hanger that the structural design already provides, with the loads (feed line 8-12 kg/m per line full, water lines 3-6 kg/m) in the member checks. The ceiling insulation (25-100 mm foil-faced PU or fibreglass with a radiant barrier) hangs from the roof purlins on 300-600 mm hanger straps, and the frame's member schedule absorbs these dead loads silently.

5. Biosecurity decides the plan. Feed silos (10-60 t), the egg or processing room, the wash bay, and the single-entry personnel flow are not ancillary — they are the layout's reason. The structural plan locates the silo foundations (a 30 t silo on a 3 m footing with seismic anchorage) alongside the gable wall, integrates the wash bay as a covered, drained slab extension, and keeps every animal-facing opening sealable for depopulation and disinfection between flocks. A production cycle of 42 days — turnover, wash-down, disinfect, restock — means the structure must also accept a pressure washer at the walls every cycle, which is why interior linings are sealed panel or sealed plywood above a 1.2 m concrete kicker, never bare steel at floor level.

When we build a barn, the value is in the 3-4% of capital that buys the right corrosion coating, the right ventilation geometry and the right service integration. The steel is the small cost — the flock's performance is the big one, and it is decided inside the building.

Poultry and livestock barns are the most site-adaptive buildings in our portfolio. The biology is the same everywhere — the climate and the local build practice are not. Our agricultural steel system ships as complete, containerised kits — frames, purlins, cladding, doors, fasteners, even the panels and ventilation hardware — with erection drawings in the client's units and a bolted, panelised assembly that a local crew erects in 4-8 weeks per barn. We have delivered agricultural structures from the tropics of Southeast Asia to the cold plateaus of Central Asia, adapting ventilation geometry, insulation thickness (25-100 mm of foil-faced PU on the ceiling) and corrosion protection to the client's climate and ammonia regime without changing the production logic.

Send us the species, the stocking density, the local climate (summer/winter design temperatures, wind zone), and the ventilation philosophy (tunnel or conventional) — we return the barn geometry, the ventilation and envelope schedule, the corrosion strategy, the complete kit list, and an erection budget a local crew can bid against. The animals set the brief; we answer it with steel.