HPH072 : A Radical Retrofit of an End of Terrace House – with Tim Nicholson
Tim Nicholson reveals why he chose to retrofit rather than build new and, having selected a suitable property, what the strategy was and why. Tim has also been blogging about the experience on his website Oxford Green House.
Interview with Tim Nicholson
After refurbishing his previous home to be more energy-efficient Tim was intrigued to take his new home, an end of terrace property, as far as he could go.
At the heart of this retrofit was a strategy using high levels of insulation and making the building extremely airtight.
Before the retrofit
Difficulties in Finding a Building Plot in Oxford Led Tim to Embark on a Refurbishment
With sites being so difficult to come by in Oxford, due to limited availability and high prices, Tim decided to address some of the problems with the UK’s existing housing stock and take on a radical, energy-efficient retrofit.
Externally Insulating the House Ensured Internal Floor Space Wasn’t Compromised
Planning restrictions led to the decision to externally insulate the building and clad it in a new brick skin, in order to maintain the existing aesthetic. They also benefited from the thermal mass, no loss of floor space and a reduced risk of interstitial condensation.
Neighbours objected to this proposed render finish
Being a Terraced Property Led to Additional Challenges
Neighbours were concerned about the ‘step’ that would be created by the additional wall, so permission was only given to clad the rear and gable walls, with internal insulation being required for the front of the house.
Laying Floor Insulation Was Ambitious and Costly
With the existing flooring being uncomfortably cold, the decision was made to dig out the existing concrete slab and the dirt beneath it, in order to lay 20cm of polystyrene EPS insulation. They found this process to be noisy, expensive, time consuming and generated a huge amount of rubble.
A “Skirt” May Have Been a Better Option
Given the challenges of breaking out the concrete slab, Tim in hindsight concedes that an insulating skirt may have been a good option. This means digging a trench down the external wall to the foundations, and laying insulation in order to insulate the walls below ground and to reduce the heat loss from the building in that area. It would not have been as efficient but would certainly have been cheaper.
Renting the House Next-Door Enabled the Family to Remain on Site Throughout the Project
It became apparent that living in the house while carrying out the refurbishment was going to have many challenges. Luckily the neighbouring house was available to rent for a time which meant they could always be there to take deliveries and ensure the site was secure.
The Layout of the House has Been Adapted to Suit the Needs of the Family
While carrying out the retrofit the family also took advantage of the chance to change the layout so that it would better suit their needs. This has resulted in a more open plan area downstairs which is much lighter and uses the new stove to heat the space more efficiently.
A Wood Burning Boiler Stove and Solar Thermal System Provide the Hot Water and Heating
The property has been disconnected from the main gas supply. The wood burning boiler stove will provide the hot water and heating at times when there isn’t enough being generated by the solar hot water system.
Refurbishing Rather Than Rebuilding Was a Better Option
With all the works taking place, and particularly given that it could be argued there wasn’t too much left of the original, knocking down and rebuilding the property could have been considered. However, being end of terrace it would have been extremely challenging with regard to the neighbouring properties.
It Has Been an Expensive but Worthwhile Process
While the works have been costly, Tim sees it as being a dual process of carrying out a high standard refurbishment and also creating an energy efficient home. Any extra investment in using the high quality products he believes is reasonable when looking at it over their lifetime.
Too Much Hot Water Has Resulted in an Underfloor Heated Log Store!
On days where there has been a lot of sunlight and not so much consumption, the large solar thermal system has continued to produce hot water to the point where it was boiling in the cylinder. Tim describes how they now divert any excess by pumping it down to their log store to help dry out the logs for winter.
Tim Hopes Their Lessons Learned Will Help Others Carrying Out Similar Projects
By sharing information on their website about the suppliers they have used, products specified, and their decision making processes, Tim hopes that anyone else doing a similar retrofit can learn from their successes, failures and experiences.
Find Out More
Visit Tim's website Oxford Green House
Download a transcript of the interview with Tim Nicholson.
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About The Author
Lucy Cowell is owner of the Virtual Assistant company Quantum PA. Being immersed in the world of architecture for over 20 years and since working with Ben Adam-Smith, she is now determined to build her own house one day too!