Glass roots - house extension design

Architectural Review, The, Oct, 1996 by Peter Blundell Jones

Volker Giencke's generous, single-storey extension to a suburban villa recalls Scharoun's domestic architecture through the creation of a series of places in an open plan.

Two of the most impressive projects in the Graz special issue (AR October 1995) came from the office of Volker Giencke, presenting a puzzling contrast. The trooped botanical greenhouses rising canted out of the ground to collide at their shared entrance seemed typical of the wilder side of the organic tradition, while the cool orthogonal plywood-clad flats in CarlSpitzweg Strasse might almost be called rationalist.

There have always been these two directions in Giencke's work, for he combines a passion for the a perspective space pioneered by Hans Scharoun with an interest in the discipline of construction more reminiscent of Jean Prouve.(1) The contrast repeats itself in his domestic work, particularly between the curved and skewed planning of the house presented here and the strict orthogonality of his own house built around a steel cage, now almost finished and to be presented in a later issue.(2)

This house is a generous single-storey extension to an existing villa in a western suburb of Graz close to the University. It had a long gestation, being initially designed some 10 years ago, though it was completed only recently. The old villa stands across the north end of the plot which is also the approach side from a tree-lined avenue, and the extension runs southward into its garden, starting alongside the villa but limited to the east by a building line. To avoid depriving the villa of light and views, the extension needed to be narrow at the point of contact, but could expand as it moved south. The treatment of the stair to the new roof terrace as an open and transparent element between the two buildings both conceals the narrowness of the neck and brings abundant daylight where it is sorely needed. Although the plan displays various curves and angles, the structure turns out to be a regular series of steel columns at 1.7 m centres supporting parallel steel beams with their bottom flanges exposed in the ceiling. They are aligned on a 32 degree shift away from the villa, the plan angle also of the glazed south wall which rises above the roof to form a ventilator.

The roof deck is a single tilted plane rising southward as the rooms get larger, the part next to the villa being a boarded terrace while the rest is grassed. The creation of this slab on posts leaves a space beneath which could be exploited in a more complex way, for plan irregularities have been absorbed by pulling the envelope back from the structure on the west side and by varying the placing of the central columns. Internally, the house is Giencke's frankest act of homage to Scharoun, for it follows the master's concern with creating a series of specialised `places' within the open plan and dealing specifically with every edge as an element of seating, storage or mediated transition to the outside.

The main space is split by a built-in sofa into upper and lower living rooms in a way reminiscent of Scharoun's Baensch house of 1935, while the corner dining-well with its seating at upper floor level recalls the Moller house of 1937. The steelwork, minimal hearth and sloping south glazing are closer in spirit, though, to the more heroically modernist and uncompromised Schminke house of 1933.(3) But what detaches Giencke's house from all such precedents and brings it into the 1990s is the frameless glass detailing, involving even a frameless glass external door closing on a glass edge. It helped that the client is the owner of one of the firms involved, and was interested and willing to experiment.

(1) The connection with Hans Scharoun is Merete Mattern, architect daughter of Hermann Mattern, Scharoun's main landscape collaborator. Giencke worked for her shortly after finishing at university and so entered the Scharoun circle. For earlier articles on Giencke and his work see ARs December 1983, pp86 83: April 1990, pp43-43: February 1992, 49 54, April 1992, pp70-72; October 1995, pp47-51 and 66-69; March 1996 pp62-64.

(2) A photo of this house under construction can be found in AR October 1995, p7.

(3) For all these examples see AR December 1983, pp59-67 `Hans Scharoun's private houses' or my Hans Scharoun, Phaidon 1995.