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The Case for Modular Buildings

posted: 5th Apr 2010

Relocatable modular buildings are the most environmentally-friendly method of construction. Generating less than 10 per cent of the carbon omissions of traditional construction and using less than 3 per cent of the energy during the build phase, modular construction has been at the forefront of sustainable building regulations. The MPBA has been involved in the consultation for the upcoming Part L changes.

At present, the UK industry produces around 10,000 modules a year, split roughly 2:1 in favour of sales: rentals. The factory manufacturing process, independently audited (ISO900) and rigorously stripped of inefficiencies, has produced wastage by up to 70 per cent, versus traditional construction. In addition, off-site construction means there is reduced on-site noise pollution, lower transport costs and, thanks to less need for excavation/groundwork, less waste. Flexibility to expand (upwards as well as sidewards) and the option to relocate add to the appeal.

But what of modular buildings' lifespan? Doesn't a shorter lifespan mean a more wasteful one? Not necessarily. The average lifespan is 18-25 years - far from 'temporary' - and with much of the material in modular construction can be retrieved and reused, saving as much as 90 per cent embodied energy versus demolish and rebuild.

The steel and insulation are by far the most significant elements, with timber, miscellaneous elements and transport each contributing only a few percent.

The internal partitions, wiring, windows, internal paint, vinyl flooring all contributed less than 1 per cent each to the total.

A total of 14,046 kg of steel is typically reclaimed from a scrapped ten module building, being the sections which are not buried within composite panel construction. The amount of energy and CO2 saved as a result of recycling of this amount of steel is 599 MJ/m2 and 42 kg CO2/m2 respectively. This is about 12 per cent of the initial total impact of construction of the building.

It is also possible that the amount of steel recycled could be increased by stripping off the steel skins from the wall and roof panels.

Versatility

Portable Buildings can best be defined as those made wholly in a factory and then transported for the installation on prepared foundations. Most but by no means all portable buildings can be removed and relocated to a new site without little or no waste.

Manufacturers produce the ubiquitous cabin in all its various guises; mounted on telescopic jackleg wheels or skids and are used for everything from an office to a store, canteen to classroom, computer suite to a hospitality suite. More recently, high security features, using steel, has added to the core appeal. The Prison Service is a customer.

Modular buildings on the other hand tend to be larger and more permanent and are produced in modular or slices, bolted together on-site in a variety of configurations to produce the clients required accommodation.

System buildings are yet more permanent because they comprise a steel or timber frame, erected on-site to which are fixed cladding panels produced by a number of different 'systems' or designs.

Volumetric units are defined as factory-built modules to site in madeup form and typically being residential designs or increasingly sophisticated hotel rooms or toilet and bathroom pods for installation in other permanent buildings.

Pricing

For an industry that has been about for some 70 years we now feel, at last, there is a realisation modular buildings are now an accepted construction option. We are, however, continually frustrated by a lack of knowledge within purchasing/procurement departments, many of which are under the impression the only way large complex buildings can be ordered delivered and installed is through tendering or main contractor route. This is not the case.

Most companies now have either a dedicated construction division to deal with groundwork and installation or alternatively work alongside bespoke companies who undertake this and the mechanical service elements. Companies also have technical departments with drawing office personnel to design buildings.

Modular businesses and associates have been undertaking this type of work for many years, eliminating the need to involve construction companies. How many people, one wonders, realise that when using a main contractor that this inflates the cost of buildings? End users should take time out to look at the alternatives within our specialist industry and talk to the companies that are dealing with this type of buildings on a daily basis.

We know from experience that many sales are costing more than necessary because clients are not purchasing direct from manufacturers. Logic tells us there will always be add-on costs such, i.e. management fees and, at times, costs incurred due to payment periods imposed by contractors. This can all be avoided by direct purchasing.

Article written by Jackie Maginnis for HEALTH SERVICE PROCUREMENT REVIEW