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Grade II listed Central London Eco Home
Prewett Bizley Architects
Contract Value
Circa £1.5M
Project Description

Prewett Bizley were seeking a contractor to completely refurbish and thermally upgrade this property. We were approached as we are one of very few London contractors with experience in Passivhaus construction and high-end finishes. When purchased, the building had been used as offices for many years; the client wanted to transform the 1820s grade II listed Georgian town house in Bloomsbury back into a cosy family home and upgrade its energy efficiency in line with the Passivhaus Enerphit standard. They also sought to add a 2 storey extension to the rear, creating more accommodation and an outdoor terrace.

Its years as an office building had left the house in a miserable state with numerous hastily thought out additions and modifications. We sought to faithfully restore and reconstruct this building, significantly improving its ability to retain and circulate heat around the house, maintaining an even comfortable temperature and fresh air throughout this 4,100 sq ft building. It now features MVHR to every room employing two Paul Focus units.

Details such as cornices, handrails and skirtings were painstakingly repaired or recreated as necessary. The windows were one of the most challenging elements of the build. In the majority of the building we had to keep existing single glazed sash windows, and we worked hard with Prewett Bizley to obtain planning permission to install vacuum glass secondary glazing. All shutterboxes had to be disassembled, a middle section built that could take the secondary glazing and then reassembled. This is a one-off project where this technique has been successfully used and this work was closely scrutinised by the local authority conservation officer who insisted that all shutterboxes retain functionality. We were pleased to meet the exacting standards of Islington planning authority and our clients.

We used a Lutron smart home system to automate lights, windows, blinds, ventilation systems, bathroom towel rails. Even though the entire system is quite complex, the client has a very simple interface that allows them to control many aspects of the building. We now design and install Loxone systems as they are more powerful and cost-effective.

A reduced heat demand following thermal upgrade allowed us to employ renewable technologies to eliminate gas from the building using Solar PV, Solar Thermal and an air source heat pump as the sources of heat for the building. Insulation materials employed included Spacetherm aerogel on the ground and 1st floor party walls, Pavadry wood fibre on upper floors, Icynene vapour open and closed expanding foam on all levels.

“Not only was the work done to exactingly high standards but Rafael made many excellent suggestions which resulted in a build which made more sense.”

– Raza R

“Hi all, just wanted to say, we are really impressed with your team in Bounds Green, they are doing such a brilliant job, and are a credit to your company.”

– Nick H

“Rafael demonstrated a great knowledge in respect of building work and was able to draw plans and give advice regarding interior design.”

– Carole R

“My projects with Bow Tie are the only ones where I’ve left the contractor to follow my airtightness details and the projects have passed the 1st airtightness test.”

– Justin Bere

“It quickly became clear that Bow Tie want to do a good job, they want their work to be to a high standard, no problem is too small to discuss and identify solutions, they really want to get it right.”

– Francis M

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