Located within the Minet Estate conservation area, this London Victorian maisonette has been transformed to expand and enhance the living and dining areas.
The design includes the reconfiguration of the lower ground floor, the extension of the rear opening, and the addition of a timber balcony on the first floor. The new and enhanced areas create a relaxing space for contemplation and gatherings with a generous opening to the rear of the property.
One of the most important considerations to our design was the presence of neighbouring properties situated above and on either side. Movement and deflection studies were conducted to ensure the interventions did not affect the surrounding flats.
Two new steel frames provide lateral stability and support the extension to the rear and the reconfiguration of the upper floors. The original plan had the ground floor wall offset from the frame with a beam and a column supporting the wall.
Our structural design brought the new steel frame in line with the existing wall, achieving a more seamless transition to the outside and reducing the amount of steel required. This solution also allowed us to use a deeper, lighter-weight beam which is easier and quicker to install on-site.
The rear extension posed several challenges including the irregular shape of the garden, the stepping-out of neighbouring walls and boundary lines, and the presence of a protected tree. To work around these constraints, we had to be creative in our use of available space for the foundations.
Due to the shallow neighbouring foundation we had to cantilever the new ground floor slab over our new foundation to avoid party walls implications. We decided to offset the trench to avoid undermining the neighbours foundations and cantilevered the beam and block floor over the trench to support the wall. We soon realised that a very shallow drain was running through where the ground floor slab was supposed to go. Close coordination with Thames Water was necessary to make sure the under floor void was maintained and the pipes were left untouched.
Internally, the space is now open and airy, with Douglas fir timber exposed throughout. While connection details for masonry and rafters are quite standard when hidden, here the joists are exposed and visible, so we had to design detailed hidden joist hangers. Concealed joists and concealed rafter details give the visual effect of rafters straight into the wall contributing to a soft and discreet look.
A timber balustrade complements the staircase becoming a highly decorative addition to the room. Our team prepared movement studies to identify its behaviour under the point loading.