A site camp: the structure is the easy part
Light steel camp buildings get priced as simple sheds, and they are simple sheds structurally. The problems that make a camp unpleasant, and eventually expensive, are not structural at all: they are sound, fire separation and the wet areas.
That is worth saying plainly because it changes where the money goes. A camp built with a heavier frame and thin partitions will be worse to live in than one built with a lighter frame and properly separated rooms.
Light steel is not the hard part
A single-storey camp block is about as straightforward as a steel building gets: a frame at modest spacing, a roof, walls, and a floor. The engineering is not where the risk sits.
The risk sits in the assumption that because the structure is simple, the building is simple. It is not. A camp is a residential building with a commercial kitchen, communal showers and a laundry attached, and those three functions bring requirements that have nothing to do with span.
So the useful division of effort is: get the frame cheap and correct, and spend the attention on the partitions, the services and the detail where water and noise move between rooms.
Acoustic separation: the wall between two rooms
In a camp, the wall between two rooms is the product.
A single layer of board on studs, with the studs continuous and the boards butted, transmits conversation almost intact. What works is mass, discontinuity and sealing, in that order: two layers with a resilient break between them, studs that do not touch both faces rigidly, and — the part that is almost always missed — a seal at the top and bottom and around every service penetration.
The junctions matter more than the wall itself. A wall that is well built and stops at a ceiling with a gap above it has a flanking path that defeats everything below. The same is true of a socket box back to back with another in the same stud bay; that single detail can halve the performance of an otherwise good wall.
Practical figures: the difference between a lightweight single-skin partition and a properly built twin-leaf partition is large enough to be the difference between hearing a neighbour's television and not — and it is a few percent of the building cost.
Fire separation in a building people sleep in
A camp is occupied at night by people who are asleep, which is the condition that drives every decision about escape and separation.
Two things follow for the layout. Rooms have to be arranged so that the route out of any one of them does not pass through another, and the distance from the furthest bed to a protected route has to be short enough that a person can use it in smoke. That is a plan decision, and it is much cheaper to make on a sketch than on a built block.
The separation between accommodation and the high-risk parts of the camp — kitchens, generator rooms, fuel stores, workshops — has to be a real boundary rather than a partition. The mistake I see is a kitchen block attached to an accommodation block with a standard wall and a shared roof, which produces a single building where the design intended two.
Where the steel frame passes through a separation, the junction is the weak point: a purlin that runs continuously over a compartment wall is a path for heat and smoke, and it needs to be detailed as such rather than left to the cladding contractor.
Wet areas: the floor and the wall behind it
Showers, laundries and kitchens are where a camp fails first, and always in the same two places.
The floor: falls that are too shallow, gullies that are too few, and a finish that becomes slippery when wet. In a communal shower block the fall should be continuous to a channel or a gully that can be cleaned without lifting a grate, and the floor should be a finish that stays usable wet rather than one that looks good dry.
The wall behind: water gets behind tiles at the junction with the floor and at every penetration, and once it is behind the finish it travels sideways into the next room. A tanked or sealed substrate behind the wet wall, carried up to a sensible height and turned into the floor, is the detail that prevents the repair in year three.
Both of these are cheap before the plumbing is in and expensive after.
Heat, and why the roof is the whole story
In a hot climate, a light steel roof over a camp room is a radiator unless it is detailed not to be.
The roof is where the heat comes in, and the two things that control it are reflectivity and ventilation of the roof space. A reflective upper surface reduces what is absorbed; an air path between the roof sheet and the ceiling insulation removes what gets through. Adding insulation alone, without either, produces a room that is hot in the afternoon and stays hot into the evening because the mass in the roof has stored it.
Ceiling height also matters more than it is given credit for: a room with a higher ceiling is measurably more comfortable at the same temperature, because the occupied zone is further from the hot surface. If a camp is being built on a tight budget, the cheapest comfort upgrade is usually a metre of height rather than a thicker panel.
What I want before drawings
- How many people, in what room configuration, and whether occupancy changes seasonally.
- The kitchen, laundry and generator positions, and what separates them from where people sleep.
- The wet-area layout, and whether floors will be tiled or poured.
- The climate: maximum temperature, prevailing wind, and whether the roof space can be ventilated.
- Whether the camp is permanent or will be relocated, which changes the jointing strategy completely.
- The wind speed to be used, taken from the applicable code at the project site rather than a round number, plus the roof fixing and edge detail — a light, wide roof with a large overhang is the most wind-sensitive part of a camp, and it is where the first damage appears.
A camp is judged by how it sounds, how it smells and whether the showers drain. None of that is structural, and all of it is decided at design stage.
Written by Johnny Joe, who advises owners and project managers in Africa and South America on steel buildings. If this decision is live on a project, send the layout and the constraint that worries you and I will tell you what it changes.
Related: a mezzanine inside a warehouse · washdown and wet areas · expansion joints in a long building · eave height
