Building’s 99% campaign highlighted the need to drastically improve the energy efficiency of existing stock. Here, Greg Slater of PRP Architects considers what needs to be done to upgrade the nation’s housing

In the drive to cut our carbon output there has been much focus on new developments but, without greater emphasis on existing housing, a significant reduction is beyond our reach.

To hit the government’s target of a 60-80% cut in carbon emissions by 2050 we need to upgrade more than 400,000 homes per year. Unfortunately, the political will to enforce these changes is constrained by reluctance to affect the private lives and castles of voters.

Issues such as national fuel security, fuel poverty and the likelihood that the world has reached peak oil production levels will inevitably bring this to a head, but it also remains to be seen how badly the credit crunch will affect the will for sustainable improvement. Developers have a habit of value-engineering out green features when finance is an issue.

Encouraging homeowners to refurbish their homes is in the government’s interest. Sustainable improvements will result in people moving less and investing more in their existing homes.

The government could set a great precedent for existing public sector stock through a new round of the Decent Homes scheme or increased support of the Housing Market Renewal Pathfinders programme, and by making carbon reduction a key objective within these initiatives. It could also encourage the private sector, as it has done for new-build schemes through the Code for Sustainable Homes and eco-towns. This would reduce energy demand and make cleaner forms of generation more viable.

Behavioural change also has a big part to play, but our industry can influence this by providing guidance and making the shift easier. Here are some issues that need to be tackled in the refurbishment market.

Victorian and Edwardian housing

Pre-1919 housing poses a range of problems. At the moment PRP is working with Wates Living Space and BRE to upgrade an existing Victorian stable block at the BRE Innovation Park in Watford. This building is typical of this era, complete with solid-brick walls, sash windows, un-insulated clay-tile roof, dampness and disrepair. Hopefully, this demonstration project, which will incorporate an exhibition space to show how the results were achieved, will be an example of how to tackle these buildings.

A lack of product innovation

We urgently need concerted product development in the refurbishment sector. In particularly, further advances in the insulation and vapour-barrier markets are vital, so we can tackle the many homes that are inappropriate for over-cladding without sacrificing internal features and floor space.

There is little competition in this sector and existing products are weak. The lack of economies of scale also means prices are inherently high.

Behavioural change also has a big part to play, but our industry can influence this by providing guidance and making the shift easier

Council stock upgrade

There is much potential to add green features to council developments. A typical example is Merchant House at the St Matthew’s estate in south London.

For this, fabric insulation is being improved through over-cladding. Energy use will be further reduced by photovoltaic panels to power common lighting and lifts.

A more complex project is the restoration and upgrade of two grade II-listed, modernist apartment blocks in Tower Hamlets, east London. In this case, over-cladding is not an option, so we are considering the use of Wall Transform’s Warm-a-Wall system. Full-height and full-width glazing in these buildings limits the zone for insulating internally to a depth of just 30mm without compromising the opening sections or appearance. Despite this, a U-value reduction from 2.1 to 0.56 can be achieved.

This is one of only two systems that we have identified that incorporates a vapour barrier to prevent interstitial condensation damaging the historic structure.

Stimulating the private sector

Some nettles need to be grasped to instigate improvement in the private sector. One idea is to use energy performance certificates to prevent the sale of homes below a certain level of energy efficiency and increase the value of better-performing homes.

Initiatives such as the Sandwell Decent Homes Partnership are an effective way to encourage private homeowners to upgrade. This offers savings on the back of larger registered social landlord-managed contracts on the same street.

At the Housing Forum Conference last month, it was encouraging to hear of contractors applying whole-life costing to projects, recognising that long-term savings can be factored in by reducing maintenance.

With growing recognition for the need to deal with existing housing stock to provide more housing today, I just hope that the current economic climate won’t scupper these developments further. We no longer have the luxury of time to let it.