What a corker

Does it make sense to replace houses built with straw, with houses built with – wait for it – cork? Definitely, says Aspire Housing which is using the natural material to breathe new life into scores of ‘non-traditional’ miners’ cottages in north Staffordshire

Despite the serious misgivings that would no doubt have been expressed at the unorthodox construction materials and techniques used to address the UK’s acute housing shortage in the aftermath of the Second World War, the homes they were used in endured for the best part of 60 years.

In the mining villages around Newcastle-under-Lyme, Staffordshire, the unusual material of choice was straw, a layer of which provided the filling for a sandwich comprising 75mm thick, brick-faced cladding on the outside, and an interior plasterboard lining.

Like the single-storey prefabs that mushroomed all over the UK at the same time, they were always intended as a temporary ‘fix’ to put a roof over bombedout Britain. And like prefabs they surprised everyone by remaining habitable – and frequently cherished – far beyond their allotted time. Eventually, though, it was clear that the so-called Cussins houses had had their day.

Steel frames corroded, and the brick panels – suspended from the frames by hooks – inevitably slipped. The homes fell well below the minimum standards of heat and noise insulation demanded by modern construction standards.

Bravely, some might say, Aspire adopted a course of wholesale refurbishment of the 54 Cussins properties – and with equal courage took the decision to employ a material to do the job that might, to the uninitiated, seem as eyebrow raising as straw.

Cork is one of nature’s little marvels. It comes from the bark of a specific species of oak, and not only is it an excellent bottle closure, but in a different configuration it also has impressive thermal insulation properties. It is an efficient sound-proofer, to boot – and crucially, its sustainability credentials are
impeccable.

The cork bark is harvested when the cork oak tree reaches maturity at 25 years. In a healthy tree, 25-75mm of bark re-grows to be harvested again every nine years, which helps prolong the lifespan of the tree for up to 150 years. No chemicals or additives are used in the manufacture of cork insulation and the process uses very low energy consumption. There is zero ozone depletion, zero global warming and cork has the lowest embodied energy of all commonly used insulation materials.

A huge variety of indigenous wildlife is dependent upon the maintenance of the cork oak forests and its production helps stabilise rural economies, populationsand local culture in the poorer agricultural areas of Southern Europe. For Aspire the decision to use such a revolutionary material – for what the
association believes is the first time in Britain on this scale – was daring, but no leap in the dark.

The association was aware that cork has been used in a similar fashion on the Continent for many years, and that over time it had proved its durability and usefulness.

Add to that the fact that it is eco-friendly, clean, dust-free and relatively lightweight, and its appeal was obvious.

“It allowed us to refurbish all of the properties without having to move the tenants out,” said Dan Gray, head of asset management with Aspire.

“Compared to traditional materials and techniques there was minimal disruption to people’s lives.”

Working in partnership with contractor Frank Haslam Milan and Alumasc, the specialist supplier of the cork panels, the £1.7 million refurbishment of 54 properties – was completed in August last year.

In addition to the installation of the cork panels and an external render finish, the facelift has included new roofs and rainwater goods, and the completed homes are indistinguishable from newly built properties.

Gray said: “We are extremely pleased with the way the contract has panned out. The work has dramatically extended the life of these properties, and done so in an affordable way that has created very little disruption. “This investment not only provides warmth and insulation benefits for residents, it has also greatly enhanced the appearance of their homes and the surrounding area.”

Worth mentioning also, is the fact that residents will face significantly reduced fuel bills in coming years, thanks to the improved thermal efficiency.

The majority of the homes converted in the first phase are in Chesterton and Bradwell, where the work has been welcomed by residents who look forward to warmer, draught-free winters.

Gray added: “We are committed to minimising the environmental impact of our work, and therefore proud of our decision to specify a natural product which has a low carbon footprint, and excellent insulation qualities – both thermal and acoustic.

“Cork provides unlimited durability for the lifetime of the homes and is naturally rot-proof and fire-retardant. It offers the performance and sustainability we were looking for and has been an important element in creating warmer, more attractive homes for our residents.”