Modular or bespoke steel buildings: start with how you will use the space

Standardisation limits the number of solutions that must be developed separately. It makes it easier to prepare components and assemble them. It also has limits. Width, height, frame spacing or gate positions may belong to a closed catalogue of options. Changing a single dimension is not always a minor adjustment. It may require different profiles, connections or foundations.

A system steel hall responds well to needs that can be clearly described and accommodated within a regular plan. An example is a warehouse for palletised goods, a garage for machinery or a simple assembly space. In such cases, the repeatability of the steel structure is a major advantage. It is easier to establish the list of components and the scope of supply.

This does not, however, mean dispensing with a design for the site. The ground, snow and wind loads, the surroundings and the requirements arising from use must be checked. The same set of dimensions does not guarantee identical load-bearing capacity. A steel hall available from a catalogue must still correspond to the conditions of the place where it is to stand.

Bespoke steel structures allow the column grid to be subordinated to a specific process. This matters with long production lines, unusual vehicle access, tall equipment or crane operation. Several naves, a mezzanine or a section of different height can be considered. Each such decision should have a functional justification.

A bespoke steel hall need not have a complicated form. Sometimes the best design is a simple rectangle with well-placed gates. Freedom should serve to remove a specific obstacle. It is not worth buying a larger span simply because it is possible. The absence of intermediate columns can be valuable, but it affects the behaviour of the frames and the cost of the whole system.

The price of the steel structure alone does not correspond to the price of the completed building. In both variants, it must be established who is responsible for the design, foundations, envelope, transport and assembly. Floor slab, services and site development may be priced separately. Only such a breakdown shows whether a standard package really meets the investor’s needs.

In a steel hall with sandwich panels, the type of envelope also matters. It is selected differently for a workshop heated all year round than for a warehouse without a constant temperature. The panel thickness does not describe all the properties of the building element. Fixings, joint tightness and fire requirements also count.

Modular steel structures can facilitate extension along the building if this was envisaged in the design. Space on the site and a suitable solution for the gable wall are needed. Bracing, drainage and the routing of services must also be checked. A repetitive frame spacing alone does not yet permit the building to be extended at will.

A steel hall designed individually can also be prepared for development. It is important to indicate the likely direction of change. Reserve for an additional nave is a different task from space for another warehouse. Good assumptions help avoid buying a reserve that the company will never use.

First draw the movement of goods, the workstations and service access. Then check whether this fits within the proposed system. If so, a repetitive steel structure may be a sensible choice. If it requires many exceptions, it should be compared with a simple bespoke design. The number of deviations from the standard sometimes says more than the advertised price per square metre.

For comparison, take the same usable dimensions, not just the external outline of the building. Check the height under the roof also at the wall, where frame reinforcements may occur. In a steel hall, plan space for access to the gates and for operating equipment. Establish which changes are available in the package and which require a new design. A ready-made set of components does not relieve you of adapting the building to its location.

Steel structures should be compared together with the envelope and the method of foundation. Pass on the requirements relating to machinery before the building geometry is approved. At a similar price, better access may be of greater value than an additional piece of floor area. The final layout should be clear both in plan and in section. Before purchase, also indicate the functions that may appear in the coming years.