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Is London meeting its sustainability targets?

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A conference at the NLA examined how the capital intends to retrofit its existing homes

Recently the NLA held a conference discussing whether London is achieving success in meeting its targets to retrofit the capital’s existing housing stock. Speakers included:

The panel covered a diverse array of opinions, best practice, pilot case studies and post occupancy evaluation.

There is high awareness of sustainability issues in policy makers but many consumers are unaware of the 80 per cent target reductions said deputy mayor for housing, land and property, Richard Blakeway. He believes successful retrofitting requires a combination of a strong policy framework and funding schemes such as the Green Deal. These have to be simple and easily accessible for the consumer and service providers to encourage uptake. To aid this he also suggested the removal of small scale obstacles such as planning permission.

Funding schemes, such as the Green Deal are predominantly aimed at homeowners

Funding schemes, such as the Green Deal are predominantly aimed at homeowners. Yet with 1 in 4 people living in rented accommodation and large numbers in social housing, tenure is a key obstacle which was raised by a number of case studies. Internal access and building works need to be coordinated for mixed tenancy and consent gained from multiple stakeholders. This can make the logistics of retrofit difficult for both occupiers and contractors. Grosvenor recently piloted a ground source heat pump buried in a shared garden of flats at Elton Square, which alleviated these issues.

Mark Elton of ECD Architects found residents of Edward Woods Estate were surprisingly resilient to the retrofit work which they carried out on the high rise estate. The work carried out gave them a renewed sense of pride for the building. Communication was found to be crucial between tenants and contractors.

Concerns of cost efficiency were highlighted in all projects. Tim Starley-Grainger stated that a decentralised community CHP in Queens Park failed, not because of initial infrastructure costs but because it was not cost efficient to run.

We need more drastic improvements to meet targets

Clarke of Grosvenor says we need more drastic improvements to meet targets, however all retrofitting works hold a price. English Heritage favour low cost solutions such as thick curtains and window restoration that does not result in loss of architectural character, whilst at the other end of the scale is the Passivhaus standard with costly engineering and equipment.

Interesting issues were raised by English Heritage who presented research of thermal studies on listed brick buildings not performing as inefficiently as previously expected. Concerns were raised in adding insulation to all types of construction. Claire Craig of English Heritage used an example of interstitial condensation causing rot due to altered permeability after adding insulation. Effective retrofitting requires the current building structure to be understood alongside an understanding of building physics. This was echoed by Andrew Mellor of PRP Architects who said there is a potential of devaluing housing stock by reducing space, usability and aesthetics.

Different retrofitting options

Marion Baeli of Paul Davis and Partners presented informative data on post occupancy data based upon three similar properties on the same street, Princedale Road. The data from a typical scheme, Decent Homes Plus and Passivhaus retrofit were compared and monitoring concluded that the mid-range scheme Decent Homes scheme achieving a 40 – 60 per cent reduction is presently most viable.

However, Baeli went on to say that we are not designing for the next 5-10 years, but rather for long term sustainability, therefore construction should be over-engineered to create a resilient housing stock. The graph below predicts that even with Decent Homes Standard renovations, by 2030 11 per cent of housing will be in fuel poverty.

Is the Capital meeting its sustainability retrofitting targets?  Sadly there are currently not enough cost effective solutions to achieve an 80 per cent CO2 reduction yet.

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