A spiral staircase and a glass-floored mezzanine gallery form the centrepiece of Picardi Architects' alterations to a third-floor attic flat in London's Holland Park. The staircase and gallery are slotted within the volume of the pitched roof. Their components - glass, steel and acrylic - were chosen to create a structure that would transmit light from a new overhead rooflight, creating a feeling of spaciousness in the refurbished interior.
The alterations address and solve some problems common to design within listed buildings. The flat is on the attic floor of a grand 'villa' designed by Francis Radford in the 1860s. It is Grade II listed and within the Holland Park Conservation Area.
In its original state, the flat had been dark and gloomy - in spite of its elevated position. In particular, the kitchen/dining space had low ceilings and although it adjoined the terrace, access and view were limited by an obtrusive utility room. The client wanted a brighter, more functional kitchen/dining area and improved access to loft storage above the bedrooms - formerly reached by means of an awkward concertina ladder.
The architect's response comprised a series of alterations, relatively small in themselves but with a dramatic cumulative effect:
the utility and boiler room was resited, creating a more spacious kitchen/dining area;
this allowed the opening to the terrace to be enlarged into a double-leaved patio door;
a new kitchen was installed;
the ceiling of the dining/kitchen was removed and an open gallery at mezzanine/loft level was created;
a new spiral staircase was installed to give access to the gallery and to the loft storage;
a new rooflight was installed above the gallery;
the terrace was refurbished with new flags and a purpose-designed balustrade.
Even though the alterations - apart from a wider opening to the terrace and a rooflight - did not affect the exterior, Picardi had to deal with objections from the planning authority.Opening up the ceiling to the loft space and new roof openings were against current local authority policy for listed buildings; similar treatments on neighbouring dormers and roofscapes was not seen to change this. 'It took a lot of patience and dialogue to overcome their objections, ' explains Gennaro Picardi.When permission was finally granted, the ceiling of the kitchen/dining area was removed and the pitched roof was strengthened, insulated and fitted with a large new rooflight, motorised and fitted with a rain sensor.
The staircase is a delicate spiral with a central circular column of satin-finished stainless steel. The triangular glass treads are fixed to the column and to a helical stainless steel string, which curves sinuously up to the gallery, supporting a curved balustrade of translucent acrylic sheets. The treads are sandblasted to give grip, except at the outer edge where small circles of clear glass have been left to allow light to shine through - a delicate tube light fitting has been placed in the corner of the wall.
At gallery level, the stair opening is flanked with a floor of laminated glass panels with a sand-blasted finish. Beyond this, the gallery is floored with sycamore boards - it is large enough to fit a desk and chair.
At night, the gallery and pitched roof profile are lit by uplighters lined with perforated steel mesh, fixed to the gallery fascia.
The new kitchen/dining room opens directly off the main hall but the staircase has been screened with a translucent glass panel to reduce its visual impact when viewed from the hall, allowing the main rooms to have more emphasis. The screen has, in the architect's words, a 'beautiful but cool' effect on the interior; it gives a hint of what is to come and transmits shadows of people going up and down the staircase. Indeed, 'beautiful but cool' sums up the whole of this small, but carefully conceived, project.
ARCHITECT Picardi Architects: Gennaro Picardi, Peter Gosney
STRUCTURAL ENGINEER Ian Drummond
CONTRACTOR Ruggles & Jeffery
SUPPLIERS Staircase and gallery fabricator Campion & Partners; rooflight Velux; lighting GSC Lighting, Erco; timber floor Junckers; ironmongery Allgood; boiler and hw cylinder Vaillant