Construction: modular classrooms

Joined-up building

21 July 2011

John Mitchell looks at a modern answer to schoolroom shortages

Modular classrooms are prefabricated buildings constructed off-site in a factory. Units can be built and prepared for shipment before the foundation is poured. The nearly finished units arrive on site to be crane set the same day the foundation is ready. They are then ‘mated’ and finished on site

In the aftermath of cuts to Building Schools for Future, modular classrooms are the contemporary equivalent of the 1960s now-discredited mobile classroom. These mobile classrooms would never meet modern standards of building control, but my organisation, Regional Building Control (RBC) has worked on more than 50 schools and pre-schools with Homelodge, a designer, manufacturer and fitter of beautiful modular timber buildings.

Such contemporary classrooms have little problem meeting the demands of building control. They often exceed the rigorous technical performance and sustainability required for the new Part L. Modular construction also has an advantage because of its consistency in design, materials and environmental standards, which can accelerate the building control assessment process. The consistency of the modular classroom means that once on site, some of the building control requirements, e.g. energy calculations, thermal properties and fire resistance, are already known.

Figure 1: In top form – interior and exterior view of a modular classroom image (Images supplied by Oakbase)

RBC’s partnership with Homelodge means that with all the changes to Building Regulations we have been able to have face-to-face discussions and agree generic designs which can be ‘rolled out’ throughout the country. This has meant that Homelodge is not subject to individual building control surveyor’s interpretations, which ultimately means we can be sure of our pricing when quoting to customers.

Points to consider at design stage

  1. As units are often raised above ground level, ramped wheelchair access is usually needed.
  2. Type of heating system and thermal envelope properties to meet 2010 Part L. Air-test results for factory-made modular buildings less than 500m2 can be based on five in situ tests on similar models to show that the air test results are better than the assumed design air permeability by not less than 1m3/(h.m2).
  3. Foundation type: sometimes pads on an existing good-quality car park or playground can be justified, but otherwise suitable new pad foundations, taken below the level of any filled ground would be needed.
  4. Provide suitable fire engine access.
  5. Careful siting of units to avoid fire spread to adjacent boundaries and existing school buildings. Site security to avoid arson should be considered.

The original 1960s mobile classroom was only meant to be a temporary two-year stop-gap but today’s modular buildings are an entirely different option. Educational bodies should see them as a cost-effective and long-term solution to poor surroundings.

John Mitchell is area manager for RBC

Further information