Nearly all portable buildings are steel or timber framed or a combination. Steel is strong but heavy and susceptible to corrosion, even after painting. Wood is susceptible to warping and rot – also many countries have strict control on import of structural timber products. Corrosion resistant aluminium and Glass Reinforced Plastic (GRP) – make up all of the external faces that is again maintenance-free and non corrosive, even in the harshest environments.
The parts are all mechanically fastened together (no welding) with simple tools. This has the added advantage in that if any part of the product is accidentally damaged, only that element needs replacing – reducing repair and replacement costs.