Spacetherm insulation keeps floor levels low

When Lister Housing Co-operative required a floor insulation that could be installed without much disruption to the tenants, A Proctor Group's Spacetherm was seen as the preferred option.

BCA Insulation was approached by Lister Housing to survey garden flats with solid floors in Lauriston Place, Edinburgh, with a view to proposing a system of floor insulation that could be installed without great disruption to the tenants or the existing form of construction.

The project is in a conservation area where any changes to the structure have to be considered.

On carrying out the survey they noted several reasons why the proposed system would have to be as slim as possible.

These included: fitted kitchen contained base units with work tops at a standard working height and any great increase in the floor could affect this; bathroom sanitaryware was fitted and boxed in, again making the option of removing and later refitting the items unattractive; the gap between the radiators and the existing floor was reasonably small and would not take much of a rise before they needed lifting; fitted gas appliances in decorative fire places with hearths didn't have much scope for movement; and doorway heights were not generous and could not be reduced any more than necessary.

Lister Housing also wished to minimise damage to the old six-panel doors in this B-Listed flat.

Taking all of the above into consideration, BCA offered two options.

Both options were able to carry domestic loading without the need for timber battening, which would introduce thermal bridging and increase the labour content.

For both options BCA calculated the insulation values using new-build thermal efficiency standards as a target.

The systems were a chipboard and urethane composite with a total thickness of 73mm (delivering a U-value of 0.22W/m2K), and an MDF and Spacetherm composite with a total thickness of 30mm (delivering a U-value of 0.25W/m2K).

Through a Value Engineering exercise, BCA demonstrated that although the urethane system was cheaper to lay, the knock-on cost was considerable as the increase in floor level would result in the skirting being replaced, sanitaryware and kitchen units being removed and lifted and the gas fires being removed and refitted involving Corgi engineers.

It would also reduce the door opening by almost 2in more than the Spacetherm option.

The client eventually chose the Spacetherm option on the balance that it included savings from being able to retain the existing skirting (as enough of it remained visible with the thinner Spacetherm option).

It would also enable the existing doors to be cut down to size rather than being replaced, which would have been necessary with the urethane option.

The works were programmed in immediately after the injection of a new damp-proof course, where BCA were involved in patching the floor screed where it had been removed as part of the damp-proofing work.

They also lifted and later re-laid the laminate flooring.

The works were carried out in one or two rooms at a time, allowing the residents to continue living in the flat during the work.

The system dealt with the slight undulations in floor level with only small areas of self-levelling screed needing to be applied by BCA.

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