working details: A timber staircase and screen
The staircase gives access to a mezzanine over the living area; together with its slatted screen it divides the kitchen/ dining space from the living space.
The concept, inspired by a slatted screen in the Giacometti sculpture room in Wohlert and Bo's Louisiana art gallery in Denmark, was to use the screen to support the staircase while retaining, in the architect's words, 'a delicacy of touch'.
The structural engineer endeavoured to reduce the sizes of timber elements to the minimum possible. The result is a screen of 70 x 35mm maple slats which are 3m high and spaced at 115mm centres. The screen is raised off the floor by fixing the bottom ends of alternate slats to a series of narrow flitch plates that rise from a steel base plate;
intermediate slats are supported on a horizontal steel strap.
At the kitchen side, a balustrade/screen of 15mm toughened glass panels gives protection to the staircase and forms the balustrade to the landing above. On this side the staircase is supported by a 40 x 40mm cranked steel string set 40mm in from the edge of the treads. Additional stability is gained by fixing each tread to the glass balustrade panel; the stainless steel fixing is sleeved in a slotted hole with neoprene pads to allow the glass to deflect.
The 870 x 265 x 40mm treads are of solid cherry to match the floor of the living area; they are fixed to each maple slat with an M8 steel dowel and the hole is filled with a maple plug. The timber is sealed with a clear satin-finish coat of highperformance polyurethane.
The steel is painted with a grey gloss coat.
The finished staircase feels surprisingly taut, with only the slightest flex.