Open House Festival

Douglas Fir House

residence, garden

Christian Brailey Architects, 2021

53 Dukes Avenue, N10 2PY

A low-energy, prefabricated Canadian Douglas fir rear extension to the garden flat of a converted Edwardian terraced house.

Getting there




Alexandra Palace


W7, W3

Additional travel info

Free on street parking.




Original Building

Shoehorned into the back of a beautiful Edwardian terraced property, the existing studio was entirely unloved and underwhelming. Every inch of wall was stained orange by cigarette smoke, the single glazing was falling out of its rotten frames and the whole place was uninsulated. This resulted in high levels of damp and extreme black mould.

However, there was opportunity in this property, which lay in its ‘good bones’ and the abundant, overgrown private garden.

Refurbishment and extension

The ambitious scheme increases the footprint by 50% to provide a separate bedroom with the ability to create a second bedroom for family growth. The new bedroom is nestled within the lush planting seen through a vast picture
window and secluded bench seat.

The central hub of the old studio has been transformed into open plan kitchen-living-dining across two levels, making it truly the heart of the home. It forms an L-shaped space, flowing into the new extension, which maximises the light - crucial to a north-west facing aspect.

The inadequate kitchen has been repositioned and replaced
with an expansive, cast concrete worktop top above deep Douglas fir plywood units. It is lit from above by a three meter long rooflight.

The split level creates a welcome division between the cosy
living space and practical, double height kitchen. But this sinking of the new floor area was also a necessary step to avoid the extension imposing on neighbours or the treasured view of Alexandra Palace which is protected as part of the Conservation Area.


The entire thermal envelope has been upgraded with high performance double glazing and natural wood fibre insulation, chosen for its breathability, acoustic and thermal properties.

All radiators have been removed in lieu of zoned underfloor heating encased in the concrete screed which acts as a heat

Mechanical ventilation with heat recovery (MVHR) provides fresh air throughout the property without losing heat.

This all contributes to the flat’s low energy consumption, calculated at just 1.3 tonnes of CO2 per year.

This is further illustrated by the energy bills still being lower than before the works were undertaken, despite energy prices and the floor square meterage increasing considerably.


From the outset, the extension was viewed as a single piece of cabinetry crafted out of a single material - Canadian Douglas fir. The very highest levels of carpentry were achieved with the extension being entirely prefabricated and erected in workshop conditions by a team of highly skilled carpenters in Devon.

The extension structure, along with all the doors and windows, was then disassembled, transported, craned-in and erected on site within a matter of days. This was also vital when working through the pandemic in 2020.


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