Web exclusive: An innovative project in Sutton is trying to tackle two major sustainable headaches – how do we address the existing inefficient housing stock and how do we know which methods of environmentally-friendly upgrades are more effective?

The Overview

The case for urgently addressing the energy performance of the existing stock of UK housing is unquestionable, given it makes up 99% of our built environment. But what is practically being done to address to need to green our stock? Civil engineer Russell Smith is in the midst of a bold attempt to discover just what is needed to upgrade an old property. He’s working on a live renovation a Victorian house just a couple of miles away from the benchmark of new build eco-housing, BedZed, in Sutton, Surrey. His work could turn out to be as influential and important as the Bill Dunster-designed housing project down the road.

The challenge

Take the standard housing type in the UK – a three bedroom Victorian semi-detached property, and embark on a unique experiment. Smith bought the house, built in 1890, in May of last year and is in the final stages of an extensive refurbishment under the umbrella of his new firm, consultant Parity Projects. http://www.parityprojects.com/. Smith has produced four newsletters on the project which offer updates on the project and look at different techniques he has used on the project.

The principle

Taking a typical house type which is suffering from typical problems such as damp etc. “To make it as much a pain in the arse as possible and see how easy or difficult it is to achieve,” says Smith. Smith’s aim is to try to reduce energy use in the house by 60% but not by throwing cash at the project. “I want to add value to the property while making the eco-upgrade,” he says. “It will make it attractive to developers.” The house will be for Smith and his girlfriend but will also double up as a laboratory – he has used different types of insulation in different rooms (see below) and has installed thermocouples inside the walls that will be connected to a computer in house to measure how well they will perform.


It will end up being between 74-80K, with 15% (11-12K) being eco-uplift. Smith estimates the payback period in saved energy bills will be between 8-9 years.


Insulation – Smith reckons better insulation will reduce the space heating requirement by 65%. The aim of the project is to “determine the approaches and materials that are cheapest to install (material and time) and the most effective in reducing energy losses. Smith has used internal insulation fixed directly to the external wall, internal insulation fixed with an air gap between it and the external wall, and external insulation where rooms are very small. He has used high energy materials such as rock mineral wool, expanded polystyrene and urethane board and natural materials such as sheep wool and recycled newspaper. The latter are more expensive to buy but use significantly less embodied energy in their manufacture.

Smith is trialling multi-foil insulation in the loft conversion he’s built. This is a controversial technique as it has yet to receive British Standard. “No-one knows whether it works or not,” Smith says.

Heating – The house has a new under-floor heating system, which compensates for some loss of space due to installation. After removing rotten timbers a layer of sand was laid before a damp proof eco membrane made from 100% recycled polythene was installed. The builder managed to place 200mm of expanded polystyrene with the system which gives a U-value of 0.15W/m2K. Concrete was placed about this, which Smith in one of his newsletters admits was a controversial choice. He sided with concrete over limecrete because of its thermal mass ability (the ability to absorb heat and release it slowly). “While concrete is relatively harmful to the environment, its durability and thermal mass properties offer benefits that provide an interesting trade-off,” he says. Smith adds that he will be closely scrutinising the performance of the concrete via on of his thermocouples.

This is not about technology, it’s about logistics. The BRE and other organisations are talking about it. I’m actually doing this

Solar Thermal – This is a “no-brainer” option for Smith. The system, which occupies a flat roof on the dormer extension and the bathroom, supplies around 60-70% of all hot water required. It costs around £3,500 and Smith reckons the payback period is seven years.

Windows – Smith is particularly excited about the Swedish window he’s installed in the loft extension. They are supplied by an outfit called Fonster and Smith reckons they are the best in the business in terms of U value (0.8) – they are triple glazed contain argon gas in the gaps.

Water – Smith has installed a cheap and relatively easy to install water management system. It consists of a rainwater collection tanks placed inside the hosue as high as possible so gravity delivers rainwater to outlets using conventional plumbing systems. It costs £250 and Smith reckons the payback period is five years through reduced water bills. He predicts an average family of four would require 110 litres/head/day at Carshalton Grove, below the average of 150l/h/d. This drop is also down to the installation of dual flush toilets, aerated taps and shower heads and not installing a dishwasher.

The interest

Smith estimates he has shown 300 people around the house, including civil servants from Government departments DCLG, DEFRA and the DTI. He held an Open House in June as part of the London Sustainability Week.

http://lovelondon.london21.org/page/64 The house was also used by the Liberal Party to launch its new policy calling for a new concentration on the existing estate. “My MP has been here six times,” he adds


Biomass – Smith was hoping to go zero carbon by bringing in a biomass boiler but claims he “came up against the system”. Due to the clean air act you are only allowed to use the boilers if they are on an approved list but Smith was unable to find an approved system for domestic use. “The only ones I found were suitable for 10 houses,” he says.


Smith took the decision to source timber frame windows as they offered the lowest cost over their lifetime and timber frames were the norm when the house was first built. This was a tricky choice as “nearly all UK manufacturers provide supply-only quotes, and local installers have their preferred manufacturers and pet frame types which rarely include timbe” he says.

What Smith learned

“This is not about technology, it’s about logistics. The BRE and other organisations are talking about it. I’m actually doing this.”