Completed in January 2017, the de Beauvoir House project contains a unique rear extension to a semi-detached family home in Hackney, London. The client brief was to remodel and extend the property, creating a two story extension that harmonised the layout of the internal spaces, making them work for their growing family’s needs. As such, the rear extension, a lightweight structural glulam timber insertion, frames a series of newly created modern spaces connected via a bespoke steel staircase. The staircase forms the new heart of the house, a meticulously detailed and sculptural point of access that defines the spaces it connects.

At the first floor, the new study/bedroom overlooks the garden via operable timber clad shutters, which visually blend with the timber structure of the extension. The lightweight appearance is further emphasised by the minimally framed glass enclosed void, which also gives height to the open plan kitchen/dining space below.

The project is a culmination of considered detailing paired with an honest approach to materiality and structure, resulting in a contemporary aesthetic that compliments the traditional terraced houses from which it extends.

In granting planning permission Hackney Council praised the project for its ‘high quality lightweight design’ as well as being a ‘good example of contemporary design, incorporated into a traditional building form’ with neighbours also praising the design as sensitive and engaging whilst allowing modern design to prevail in a heritage area.

The project commenced on site in November 2015 and work was completed in January 2017. Sustainability Statement: The project was designed to adhere to energy demand requirements, however particular focus was placed on the new build elements. The material choice of using a timber glulam frame provided a relatively sustainable solution compared to steel. The large amount of minimally framed glazing needed to construct the lightweight enclosure to the bespoke steel staircase was scrutinized to avoid any cold bridging issues and condensation risk. Sustainable solutions were resolved after analysis and collaboration with environmental consultants, Enhabit.

Webb Yates Engineers completed the structural design for the extensive refurbishment and extension of De Beauvoir House, a large Georgian semi-detached house in London. The main works involved opening up the lower ground floor and constructing a new glulam frame extension to the rear.

The original building was relatively neglected so in addition to the new extension extensive repairs and strengthening works were carried out to the existing structure. In order to retain as much as possible of the original structure the work was completed in the least intrusive way possible. The ground floor area was completely opened-up with a new complex steel portal frame installed to support the rear façade and provide stability to the structure. By working closely with the architect we developed a structural solution that was cost-effective and enabled as much of the space to be opened up as possible.

The rear extension is formed of a series of cubed frames of 240mm square larch glulam beams with steel plate connections. To create a large opening at the rear, the glulam beams form a Vierendeel truss with moment-connections to enable them to span over a double-width glazed window. This frame is exposed and was carefully detailed to work seamlessly with the surrounding finishes.

Material Used :
1. Lightweight structural glulam timber extension