Steel Structure Chicken House

A clear-span frame is what allows cage rows, feeder lines and drinker lines to be laid out on the grid the equipment requires.

Start with four numbers, not a footprint

A chicken house can be quoted per square metre. It can only be designed against production data. These are the four inputs we ask for on the first call, and what each one changes in the steel.

1. Bird type and cycle. Broilers to 2.4–2.8 kg in 35–42 days, layers in lay for 70+ weeks, breeders on controlled feed. Cycle length sets how many flocks run through per year — and therefore how many full washdowns and disinfectant cycles the coatings have to survive. A house on a 42-day cycle with 14 days of downtime turns over six or seven times a year.
2. Flock size and stocking density. A floor-raised broiler needs roughly 0.075–0.09 m² at target weight; cage-free layers need appreciably more. 30,000 broilers lands around 2,250–2,700 m² of floor. That figure sets the footprint. The budget does not.
3. Ventilation mode and target air speed. Tunnel houses are designed around 2.0–2.5 m/s at bird level, with a full air change in under 60 seconds. Naturally ventilated and semi-open tropical houses are designed around cross-flow and ridge extraction instead. Different cross-sections, different eave heights, different frames — and switching between them late in the process is expensive.
4. Site wind speed and terrain. A 3-second gust figure plus an exposure category. In typhoon and cyclone markets — the Philippines, coastal Vietnam, the Caribbean, northern Australia — this usually governs the frame more than the birds do.

Send those four and design can start the same week. Send only a footprint and a price-per-square-metre target and you will get a building that stands up.

Span, height and roof shape

Clear span comes first

Cage rows, feeder lines and drinker lines are set out on a fixed grid. A column in the wrong place costs you a row of cages or forces a corridor you never planned for. Tunnel houses mostly sit in the 12–18 m clear-span band: wide enough for four to six cage rows or a full-width floor layout, narrow enough that the roof does not become the expensive component. Wider spans are buildable, but weight and cost climb faster than linearly once you pass about 18 m.

Eave height is a ventilation decision

Not a comfort one. Naturally ventilated houses run low — 2.4–2.8 m — so air sweeps across the birds. Tunnel houses run higher, 3.0–3.6 m at the eave in hot climates, because the cross-sectional area sets the air speed you can reach with a given fan wall. Our three-house project in General Santos, Philippines sits at 110 × 15 m with 5 m overall height for exactly that reason.

Interior height and uninterrupted floor area decide what stocking density and equipment layout are actually achievable.

Roof pitch

Normally between 10% and 15%. Steeper sheds monsoon rain faster and adds volume above the birds, which helps in hot weather. The double-slope roof on our 1,870 m² Philippines shed (110 × 17 × 5.05 m) was specified for drainage before anything else — in a climate where a week of monsoon rain can deliver 200 mm, water standing on a flat roof is a structural load, not a maintenance chore.

Wind and uplift: the case that usually governs

A poultry house is a light building with a very large roof area. That is the worst possible combination for wind uplift. At the eaves and at the ridge, the governing load case on an exposed site is frequently net suction rather than downward pressure. Two practical consequences follow.

• Hold-downs need designing, not checking. Anchor bolts and column-base details sized from experience rather than calculation are the thing we most often end up correcting in drawings we inherit from elsewhere.
• Openings change the pressure regime. A large open side on the windward wall pressurises the interior and adds to uplift on the leeward slope. Semi-open and curtain-sided houses need both the open and the closed case analysed.

We design against whichever wind standard your local engineer or authority nominates — ASCE 7, AS/NZS 1170.2, EN 1991-1-4 or a national annex — and we issue the load calculations with the drawing set, because your permit office will ask for them.

Specify the enclosure for ammonia, not for price

Working houses carry somewhere between 10 and 50 ppm of ammonia, with relative humidity above 70% for much of the flock. Ammonia dissolves into the condensation that forms overnight on cold steel, and it attacks the zinc layer that is supposed to be protecting it. That is the mechanism, and it is why light commercial galvanising gets consumed inside poultry buildings while agricultural-grade coatings in the Z180–Z275 g/m² band are still sound at 15–20 years.

Panel selection follows the same logic. On the General Santos project we paired a hot-dip galvanised frame with 50 mm EPS sandwich panels — colour-coated steel outside, PVC facing inside. The PVC is not there for looks. It survives weekly high-pressure washing and the chlorine-based disinfectants that break painted surfaces down within a few seasons. Where a site sits close to the coast, or runs a particularly aggressive cleaning regime, a duplex system — galvanising plus an epoxy or PVDF topcoat — is worth the premium. Where it does not, it is not.

Panel facing material matters as much as panel thickness: the inner skin takes the washdown, the disinfectant and the ammonia.

For tropical sites the question of which cladding and coating combination suits which climate is treated at greater length in our guide to enclosure materials for tropical climate zones.

Do you actually need insulation?

Often less than people assume, and in the wrong place when they do.

• Hot-humid tropics — the Philippines, coastal Thailand, much of coastal Latin America. Wall insulation buys very little when outside air sits at 30 °C and 80% RH day and night. Money goes further on roof reflectivity, ridge extraction and, above all, air speed. Insulated ceilings still pay for themselves over brooding areas where you are heating day-old chicks.
• Temperate, continental or high-altitude sites. The ceiling is the priority, not the wall. Condensation is the real enemy: warm moist air meeting a cold roof sheet drips onto litter and birds, and wet litter is where ammonia and footpad problems both begin. Our Albania poultry house (10 × 50 × 3.7 m, portal frame) used EPS sandwich panels precisely to hold a stable, non-dripping ceiling over chicks.
• Hot-arid climates. Karachi is a different problem from General Santos. Insulation earns its keep at night and during cold snaps, and the larger design driver is usually pad-and-fan capacity rather than panel thickness.

What the frame has to carry besides itself

A poultry house carries more suspended equipment per square metre than almost any other farm building, and nearly all of it hangs off the roof structure.

Send us the equipment layout before the frame is designed. Retrofitting hangers into a completed roof is the expensive version of this conversation, and we have had to do it often enough to be blunt about it.

Where we tell clients not to use steel

This deserves its own section, because it comes up on most tropical poultry projects.

Steel is not the best material for the bottom metre of a wall that gets hit by feed carts, scraped by loaders and pressure-washed weekly. Masonry is. On our Thailand chicken shed the design — built to the client’s specification — uses concrete columns with a 1.3 m brick plinth wall and EPS sandwich panels above. The plinth takes the impact and the washdown; the panels above stay light, insulated and quick to erect. In that situation it is a better building than an all-steel one, and we would specify it again.

The same logic applies to ventilation capability. If your house is naturally ventilated, open-sided and sits in a mild climate, a lighter semi-open shed structure will cost less than a fully enclosed tunnel-capable frame and perform identically. Do not buy tunnel capability you are never going to use.

What we supply — and what we do not

Standard configurations, sizes and pricing bands are listed on the steel livestock shed product page. If you are comparing suppliers rather than drawings, our buyer’s guide sets out the nine checks to run before you place an order with any Chinese fabricator.

Reference projects

Other poultry work includes a 1,360 m² house in Cebu built on Q235 H-beams (80 × 17 × 4 m), a free-range house in Zimbabwe, and the Thailand shed above with its masonry plinth. Our Philippine chicken coop project shows a smaller single-house layout. The wider set sits under livestock buildings.

Typical specification ranges

These are design ranges, not stock sizes. Your wind case, bird type and equipment layout decide where in each range you land. Standard configurations and current price bands are on the livestock shed page.

Frequently asked questions