Prefabricated buildings have long ceased to be “temporary site cabins”. Today they are warehouses, production workshops, retail pavilions, workers’ camps, administrative and welfare blocks, medical stations and even schools. Clients are attracted by the timescales: a building made of a steel frame and sandwich panels can be put into operation in two to four months, whereas conventional construction of the same size takes a year or more. But building fast is not always cost-effective. Here is how to make the decision based on numbers rather than gut feeling.
What counts as a prefabricated building
The term usually covers several technologies with different economics and different service lives:
- factory-finished modular units — volumetric sections with finishes and services that are delivered to site and joined together;
- light steel structures (LSS) — a frame made of cold-formed or hot-rolled sections clad with sandwich panels;
- frame-and-membrane hangars — the most budget-friendly option for unheated storage and seasonal needs;
- demountable buildings — structures designed to be relocated to a new site.
They all have one thing in common: most of the work is done in the factory, leaving the foundations, erection and utility connections for the site.
When a modular building makes more sense
The savings come not from the cost per square metre — which can be comparable to conventional construction — but from time and flexibility. A modular solution is justified if:
- Time to launch matters. A warehouse that starts generating income eight months earlier often more than offsets any difference in the price of the structures.
- The facility is needed for a limited period. A workers’ camp for the development of an oil or gas field, a site office, a temporary school during reconstruction — here permanent walls simply will not pay off.
- The site is remote. In the steppe, delivering ready-made modules is easier than setting up a concrete batching plant and keeping crews on site for months.
- Large column-free spans are needed. A steel frame easily spans 24–36 m, which is convenient for warehouses and workshops.
- The business plans to expand. It is easy to add a new bay or extra modules to a framed building.
When conventional construction is the better choice
Lightweight structures have limitations worth bearing in mind before signing a contract. A conventional building is preferable for multi-storey housing, facilities with high fire-resistance requirements, premises with heavy process equipment and high-capacity cranes, and wherever the building must serve for 50 years or more without major investment.
Climate is a separate issue. Kazakhstan’s sharply continental climate means temperature swings from −35 °C in winter to +40 °C in summer. For a heated modular building in Astana or Karaganda, the insulation thickness in the panels and the quality of junction details are critical: saving 50 mm of mineral wool will result in frozen joints and hefty heating bills as early as the first winter.
Seismic and snow loads
A light frame performs well in an earthquake thanks to its low mass, but that does not exempt it from structural analysis. In Almaty, Taraz, Shymkent and other seismically active areas, the design must comply with Kazakhstan’s standards for construction in seismic zones: bracing, column-base connections and anchorage. In the northern regions, snow load becomes the main factor — it is the most common reason cheap hangars assembled without a design collapse.
A prefabricated building only saves time when it has a proper design. Without calculations, “fast” easily turns into “twice”.
Foundations and utilities
A common misconception is that a lightweight building hardly needs foundations. In reality, an LSS frame most often sits on cast-in-situ pad foundations under the columns or on a pile field, while modules need strip or raft foundations. The foundation depth is determined by soil conditions and frost penetration, so site investigations are needed here too. Connections to power, water, sewerage and heating are budgeted separately: on remote sites these costs are sometimes comparable to the cost of the building itself.
How to compare the options
A proper comparison considers not only construction cost but the full life cycle of the facility:
- the cost of foundations, structures and erection;
- time to commissioning and the income the building will generate during the months saved;
- operating costs — heating, roof and facade maintenance;
- service life and residual value, and the possibility of dismantling and relocation.
You can get a rough idea of the cost in our online calculator, and for an accurate comparison of two technologies our engineers will prepare estimates for both options — see “Cost Estimating” for details. Examples of warehouses, workshops and office buildings we have already built can be found in the “Projects” section.
Techno-Module has been working as a general contractor since 1994: we design, estimate and build both modular and conventional facilities with our own equipment and crews in Almaty, Astana and Taraz. Send us a request — we will help you choose the technology that pays off for your specific project.
