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  • PublisherCIBSE
  • Product Code
  • Number of pages0
  • Publication DateFeb 2016
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CIBSE Case Study: Clapham Retrofit, London - Arboreal Architecture

CIBSE Case Study: Clapham Retrofit, London - Arboreal Architecture

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CIBSE Project of the Year Residential

Recognising the new build or refurbishment of a building in the residential sector that most effectively demonstrates high levels of user satisfaction and comfort whilst delivering outstanding measured building performance.

Clapham Retrofit, London - Arboreal Architecture

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An imposing 170-year old Grade II listed Victorian townhouse in Clapham has undergone a deep retrofit to become the first listed building in England to meet the AECB Silver Performance Standard.

The retrofit design objectives for the four-storey semi-detached masonry building were to:

  • Sensitively restore the structure and fabric of the house respecting original features.
  • Open up the dark lower ground floor into a light-filled stepped courtyard.
  • Thermally upgrade the house following English Heritage retrofitting best practice.
  • Create a comfortable home fit for the future.

Following consultation with English Heritage and the conservation officer, the condition of the building's fabric was investigated, as were key elements of historic significance and the existing thermal performance. Before design proposals were developed, measuring and monitoring expert ArchiMetrics carried out airtightness and thermographic surveys, U-value measurements and interstitial moisture monitoring to deepen the project team's understanding of the building and allow a finer grainof design and specification.

The key technical innovation in the project lies in its approach towards the specification of the internal insulation to the roof, floor and walls. Nine key insulation materials (including woodfibre, aerogel and cellulose) were installed, responding directly to localised historic fabric and performance requirements.During installation, workmanship and airtightness detailing were monitored and wireless sensors were fitted.

Other energy efficiency technology installed included LED lighting, solar thermal panels, Stelrad radical radiators, MEV ventilation and double-glazed secondary glazing.

Using Passivhaus methodology, the estimated space heat demand of the 170 sq m building has been cut by more than 75% from 180kWh/ m2/yr (5,631 kgCO2e) to 40kWh/ m2/yr (1,251 kgCO2e). Air leakage has been reduced from 9.6ach to 1.8ach. Measured actual gas energy use for the year from January 2014 (9,146kWh) was under the predicted energy demand of 9,619 kWh.

Since the building has been occupied, its internal temperature has remained at 20C and the internal relative humidity has stayed within 50-60%. One occupant reported that the even temperature and humidity made the housing extremely comfortable to live in.

Project Team:

Building services engineer and mechanical / electrical engineer: Alan Clarke
Building owner and occupier: Simon and Veronica van Heyningen
Project manager, quantity surveyor and architect: Arboreal Architecture
Contractor: Noble & Taylor
Structural engineer: The Morton Partnership

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