Project spotlight: Surrey’s eyesore to eye candy

Devising bespoke cladding to refurbish a 1960s eyesore, Mulalley also had to ensure residents were not disrupted. Operations director Colin Watson talks CM through it.

Describe the project

The overall project cost £9m and involved the refurbishment of Chaucer House, in Sutton, Surrey. The 17-storey apartment block is Sutton Housing Partnership’s oldest, built in 1965, and has 96 flats.

The cladding on the original building had fallen into disrepair and needed replacing. Originally the building had precast concrete panels which had failed and were replaced in 2013, but these had also begun to fail.

What did the works entail?

A solution had to be found whereby the residents could remain in occupation while the works were carried out.

Building consultancy Pellings worked with its structural engineer to devise an outline proposal for fixing of the new cladding system. This involved building an exoskeleton-type system over the existing cladding to provide structural support for the windows which could not be supported within the existing openings.

The 1965 17-storey block was in disrepair and the cladding was failing

Pockets were cut through the existing panels to accommodate bespoke brackets, attached to the concrete floor slabs, onto which the new supports, panels and windows were to be fixed.

Utilising the existing GRP panel served two purposes: first, to provide a rigid backing for the insulation to be fixed to; second, to provide safe separation from the internal parts of the building so residents would not be disrupted.

Inside, two lifts were replaced and the entrance lobby and landings refurbished in addition to a roof level structure which was renovated to provide a viewing gallery.

How did the project differ from other cladding schemes you’ve worked on?

A bespoke solution was required as the existing cladding (which was to remain in place) could not provide adequate support for the new windows. The existing cladding itself had replaced the original cladding and the fixings for both were a potential problem.

You became involved in the project early, how did this benefit the overall works?

We provided structural surveys which established the condition of the concrete, following which arrangements were made to remove some of the existing cladding panels at low level to determine how these were fixed.

This enabled us to establish very early on – and subsequently make time and cost savings – that regardless of the type of new cladding system to be selected, additional structural primary supports would be needed to give support to the cladding and new windows.

What was the biggest challenge?

The setting out of the bespoke brackets and supporting framework to enable
the insulation, windows, and cladding to be fitted.

What has been the biggest lesson learned?

The project served to reinforce that by taking an inclusive approach at the outset of a project significant amounts of time and energy can be saved through early collaboration.

An exoskeleton-type system was constructed over the existing cladding