R20: Stock Orchard Street Retrofit

Twenty years after completion of the buildings, we undertook a refurbishment of 9/10 Stock Orchard Street. The first phase focused on reducing the energy demand of the house and improving user comfort.

A comprehensive energy assessment was carried out and the proposals for R20 included retrofitting measures to ensure optimum building performance for the 20 years to come.

The project also incorporated design proposals for ageing in place. User-friendly alterations in the bathroom, kitchen and circulation ensured the building is practical and adaptable for the future.

You can learn more about the 20+ and 60+ improvements at Stock Orchard Street here.

Client: Jeremy Till and Sarah Wigglesworth

Completion: 2019

Location: Islington, north London

Awards:

2021 AJ Retrofit Award (Highly Commended)

Publications:

R20 narrative

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Financial Times

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Architecture Magazine – Question Time

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Financial Times – House & Home

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Evening Standard

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RA Magazine

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German Architectural Digest Magazine

Dezeen

Fabric

Elle Decoration

Modern House Magazine

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In 2017 we appointed Enhabit, an environmental consultancy, to undertake a thorough assessment of how the building was performing in terms of fabric efficiency and energy demand. This enabled us to benchmark the resulting data against current energy standards. The assessment methods included thermal imaging, airtightness tests, measuring u-values of the building fabric, analysis of energy demand using Passivhaus software, as well as monitoring energy bill data.

This research highlighted key elements of the building fabric that could be improved. The R20 project focused on the items that will have a significant impact on reducing energy consumption of the building and enhancing user comfort. These included:

Improving airtightness
Reducing thermal bridging
Improving ventilation
Improving solar control.

Energy analysis: house (data courtesy of Enhabit)

Energy analysis: office (data courtesy of Enhabit)

In the process of improvements almost every junction in the building was taken apart and put back together again – only better.

Increased airtightness was achieved by installing airtightness tapes at floor-wall junctions and around incoming services. Thermal bridging was addressed by adding insulation and ensuring its effectiveness, working with the airtightness measures in key areas. Underperforming components such as roof lights and windows were replaced to reduce heating demand. For improved ventilation, the existing MVHR units were replaced with products up to current standards. External shading was incorporated on the south west elevation of the house to reduce glare and overheating.

Before and after data analysis (data courtesy of Enhabit)

The results of the retrofit are heartening. Uncontrolled air infiltration has been substantially reduced. The insulation levels of the south-west elevation, the first floor soffit and the tower have been improved so that CO2 emissions have been reduced by 62%.

Over 20 years of occupation we know that many aspects of our home give us great pleasure and perform well. Building on this, the retrofit allowed us to also consider some alterations to the house to ensure we could continue to live well as we grow older. While the environmental improvements will offer greater comfort, other functional improvements were anticipated. Accordingly, a level-access shower was installed in the bathroom. The gas hob was removed and replaced with an induction hob and the below-worktop oven was replaced with an eye-level one to avoid bending down.

The utility room on the ground level was converted into a separate kitchen for a carer, should one be required in future. Together with the bedroom and separate bathroom this makes the ground level effectively a private suite.

Grab rails were installed in the bath surround and handrails were added to the stair and bridge balustrade. A site was identified for a potential future lift if this were to be required. These adaptations ensure that we can remain safe in our familiar environment into the fourth age while continuing to enjoy the benefits of a home and garden close to the centre of London.