Oxford Method Research Programme

Partitions

This substitution of thinner plasterboard may also be considered for internal partitions as well as for the inner lining of the external wall. (Note that HTM guidance generally describes a nominal 100mm partition as being faced in two layers of 9.5mm plasterboard, i.e. nominal 20mm plasterboard/60mm metal study/20mm plasterboard; rather than 25/50/25 as in "6M" construction).

Standard 6M partition construction comprised British Gypsum Ltd gypsum wallboards, fixed to galvanised metal studs using self-tapping screws, and with tapered-edge facing boards allowing joints to be taped/filled, and the partitions otherwise sealed and directly decorated (i.e. not given a plaster skim coat). Installation was usually by a nominated sub-contractor.

These materials remain available and this form of partition remains commonplace.

However, standard gypsum wallboards have a number of performance limitations, including:

• Limited load-bearing capacity at heavy fixtures such as radiators, necessitating additional design co-ordination for the installation of noggins and local ply strengthening layers
• Limited moisture resistance, necessitating specification and site monitoring of water-resistant grades of plasterboard in wet areas
• Limited fire resistance, necessitating specification and site monitoring of fire-resistant grades of plasterboard at compartment and sub-compartment walls
• Limited resistance to impact damage

Currently-available enhanced gypsum-based boards have greatly-improved performance in these respects, are now commonly used (for instance in current PFI projects such as Princess Margaret Hospital, Swindon) and should be considered as an alternative partition construction when matching or adapting 6M buildings.

Lafarge Ltd 'Megadeco' boards are one example of such enhanced products.

Significant economies of materials and labour may be achieved, as a single facing layer gives comparable partition performance to the two layers required when standard gypsum wallboards are used, and as the white board finish allows reduced decoration work.

Column casings

15mm Glasroc S Frameless Encasement System is currently marketted, suitable to give one hour fire protection to the RHS structural columns at room level. (see notes on ceiling construction in respect of fire protection above ceilings)

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