West London townhouse doubled with ‘secret’ extensions IBLA have almost doubled the space inside this typical London townhouse with the addition of a pair of ‘secret’ new floors at the top and bottom of the property. The clients, a pair of doctors, wanted to add more space whilst maintaining the existing character and external massing of the original house, and keeping their garden intact.
IBLA embraced the idea that the changes would be discreet and as such the usual solution of adding a ground floor rear extension was rejected from the outset. The intention became to re-configure the house in a sympathetic and respectful manner, including a refurbishment of the existing house, a total re-build of the roof, and a sizeable basement extension. Firstly, a new rear-facing loft extension was ‘hidden’ behind the retained brick gable end of the existing roof. This provided a new ‘children’s floor’ with a shared space for the kids, leading onto a pair of bedrooms with glazed walls concealed behind the retained gable.
The lofty, light-filled space, lined in painted timber-boarding and decorated in muted greys and pinks, provides a generous play area - and is a spectacular culmination to the main staircase of the house. The existing traditional stair from the ground floor entrance to the first floor landing was extended upwards in a similar soft palette of painted timber. A gently curved stringer echoes an existing arch; and the new stair handrail is designed to open up towards the top, allowing views and light down to the rest of the house. At ground floor, the existing kitchen, dining and utility areas were removed, and a generous new kitchen space was created across the entire rear, with glazed sliding doors opening into the garden.
A small side extension housing a pantry and cloakroom was added, enabling direct access to the new kitchen from outside. This small functional move had a significant effect on the family’s daily life: facilitating kids' arrival and exit, deliveries and shopping, and creating bike storage. The existing ceiling over the kitchen was replaced with weathered French oak beams. A painted timber boarded ceiling was also introduced, this time painted in a warm grey. The chunky beams are contrasted with the finely detailed oak kitchen cabinets, which have been designed as a series of pieces of furniture. The kitchen connects to the living room via a library. The first floor layout was rationalised to include a master bedroom suite, a study and guest accommodation. The master bathroom was carefully designed to preserve the existing fireplace and features panelling and a tiled floor.
Below ground level, the enlarged basement includes a bedroom with ensuite, a laundry room and a large recreation room, with a vaulted ceiling extending under the new external deck. Glazed doors open into a sunken garden, which also provides access to the rear garden via an external staircase. This recreation room provides a calming space for adults to relax in and serves as a counterpoint to the kids play-space up in the roof.
What are the sustainability features?
Existing buildings present their own issues when it comes to sustainability. The potential benefit of a new efficient building fabric needs to be measured against the actual cost in embedded energy inherent in reconstruction. Even then, there is an uncertainty in making such an assessment; any possible future gain in terms of CO2 emissions fundamentally depends on the evolution of the UK’s energy generation as a whole.
Moreover, the wider existential issue of the value of retaining historically significant construction against the benefits of energy efficiency is even less easy to quantify. In this case, while not listed, the original house is a fine example of Victorian building and retained a number of distinctive original features, which in our view were worthy of preservation in their own right. At the same time the existing house fell some way short of the needs of the new owners and was in need of substantial repair and refreshment. As such, each element of the existing building was assessed at a number of levels: could it be retained, repaired, adapted or did it need complete replacement or redesign. With an eye both on sustainability, and as an attitude to the character and philosophy of the final building, the decision was made to retain and repair as much of the original fabric as was feasible.
Where fabric was to be repaired it would be upgraded thermally if possible and where it was to be replaced it would be constructed in accordance with contemporary best practice. New fabric would be both thermally efficient and sustainable in specification. Heating systems were replaced with modern efficient equipment with sophisticated controls. Underfloor heating was installed throughout, and the existing floorboards were then re-laid where possible to minimise waste. Existing elements like the terracotta chimney pots from the existing roof were re-used as planters, and fireplace surrounds carefully reconditioned and reinstalled.
