Carlton Chapel House sits on a corner plot between Arctic Street and Gilles Street, in Kentish Town, north London. The site previously housed a corrugated tin chapel. It is a three-storey building with 15 units, designed and built in 1983. The design was well received by the architectural press who called it, ‘cheerful and youthful among older neighbouring buildings.’ However over time it became apparent that there were several long-term problems related to its design and construction.
The building suffered from cold bridging which as fuel prices doubled led to a rise in condensation and mould growth. We initially tried to tackle the thermal performance of the building by filling cavity walls and adding insulation to the roof. This was a minor improvement; however, the design meant that certain areas couldn’t be insulated, and it did not solve the problem. Additionally the building and a number of its components were reaching the end of their economic life and required overhauling, redesigning or indeed replacing.
APPROACH TO SOLUTION
In 2011 the Co-op commissioned a feasibility study to look at the options available, these were filtered down into three main areas:
Renovate, incorporating development of two extra units on the roof
Traditional renovation of the building, without addressing the underlying design issues, knowing that further costly major works would be needed in the future.
Take a bold step in securing a substantial £1.7 million loan, as well as a significant capital investment, to commission an environmental redesign and renovation of the building.
It was decided to go ahead with the last option and address the underlying design issues to provide a sustainable, future-proofed building for the next 60 years.
Members decided to follow the Passivhaus concept which involved upgrading the building with external insulation, triple glazed windows, good levels of airtightness and heat recovery ventilation, which gently provides fresh air and removes the stale air. The opportunity was also taken to redesign the five bedsits in the property into one-bedroom flats, whilst keeping the integrity of the original design. As the heating load was reduced greatly the gas supply has been completely removed from the building and Photovoltaic roof panels were installed.
This meant that any electricity generated can be used freely, if its not consumed the electricity automatically goes to heat the water in individual flats. This will significantly reduce energy consumption, with heating and hot water bills reduced by up to 90% for tenants.
The drive behind the decision came from members enthusiasm to create social housing that is more environmentally friendly and fit for the future. There were detailed discussions and consideration for this project, it was a massive commitment for a small housing cooperative of 106 units. This preparation has led to the scheme being fully funded within NCHC’s cash flow for the next 30 years. Completed in 2019 the building has received passivhaus ‘enerfit’ certification. Monitoring is currently underway. Carlton Chapel House is a truly sustainable and innovative solution fit for the future.