Brandon Mews roof canopy

In the early years of the development, Brandon Mews, suffered severe water penetration problems. Remedial works were undertaken in 1983 and in 1985 and involved replacing the roof coverings and reconstructing the paved areas on each side of the 13 ‘wigwam’ roof structures.

But this didn’t solve the problem and in 1987, the Barbican Residential Committee reported that water penetration problems continued, that they were causing serious inconvenience to the residents, and that this was due to a fundamental flaw in the design of the podium structural slab.

They instructed Atkins Sheppard Fidler & Associates, consultant architects, to examine the problems and put forward possible solutions. They came up with three options. They are recorded in the report of the Barbican Residential Committee to the Court of Common Council, dated 12 March 1987.

Option A – Do nothing or defer action. This involved doing piecemeal remedial works. This was rejected because it would involve carrying out extensive remedial works, again and again, without resolving the underlying problems. Deterioration would increase water penetration. More of the flats would become uninhabitable. Life would be intolerable for existing tenants. The committee concluded, “This option cannot, therefore, be contemplated”.

Option B – Renewal of the roof coverings. This involved breaking up the paving between the wigwam roofs, laying a Butyl rubber waterproof membrane over the asphalt and then relaying the paving slabs. This was going to cost a lot of money, and the consultants couldn’t even be certain that such a solution would succeed. This option was rejected because the Director of Building and Services had no confidence in it, and the committee felt they had to come up with a guaranteed cure which would also cause minimum disturbance to the tenants.

Option C – Provision of a roof canopy. The architects recommended that a canopy roof, with a steel frame and polycarbonate barrel vaults would present the best solution to the problem of making Brandon Mews watertight.

A barrel vaulted canopy roof was recommended because this would reduce the height of the canopy roof to a minimum, thus limiting its visual impact on residents living in the lower floors of Willoughby House, which overlooks Brandon Mews. It was felt barrel vaults would also retain the continuity and unity of design within the residential estate because they would be repeating the barrel-vaulted roofs used on all the main residential blocks.

There were concerns about heat build-up. But it was decided that the potential problems of heat build-up under the canopy roof are “not insurmountable” and could be solved by within the technical design of the roofs.

This was the most expensive option, but the architects considered that maintenance costs would be quite low. For the most part, maintenance would be limited to occasionally cleaning the polycarbonate cladding and the metal framing. The metal would be coated so that there would be less need for repainting, at least for the original first 10 years. It was estimated that the lifespan of the structure of the canopy roof would be 60 years, although some of the polycarbonate cladding might need to be replaced earlier if there was any deterioration due to ultraviolet degradation.

So this solution, although the most expensive in capital terms, would provide the best result over the long term. The big attraction of this solution was that it would cause least disruption to the occupiers of Brandon Mews flats who had already suffered water penetration and had to endure two unsuccessful attempts to cure it.

Since the surrounding blocks were now occupied by tenants, it was necessary to go through a consultation period. But the works were carried out in late 1987.