Double dutch.

A brave attempt to weave mixed-use interventions into a delicate urban fabric with uncompromised Modernity, yet respect for the texture and nature of the quarter.

Context is now such an overused word as to be almost meaningless. Its iteration in the 1980s by architects intent upon the maintenance of European cities produced problematic quantities of historicist kitsch. Perhaps texture and weave are more useful terms for a fully responsible urbanism. The recent social housing projects by Felix Claus and Kees Kaan knit themselves into the cityscape of Amsterdam so as to be simultaneously respectful, practical and unabashedly modern. They are part of a new wave of Dutch design which addresses, unsentimentally, normal metropolitan life.

Arriving at the city's Central Station, you turn west past Dudok's isolated Harbour Building (1960) and the elegant curve of Rudy Uytenhaak's De Droogbak residential complex of the late 1980s. De Droogbak - on which Claus collaborated before establishing his own practice screens the intimate scale of the Haarlermmerbuurt from the hustle of marshalling yards and the exposed, increasingly defunct harbour to the north. Running east-west, the Haademmerstraat is the district's rather rambunctious High Street, Binnenwieringerstraat a side lane leading towards the inner-city canal system.

The buurt or neighbourhood is a typically Dutch accumulation of houses, modest units of commercial, professional and residential accommodation marked by their verticality and by a happy mix of styles from mercantile vernacular to neoClassical and from Jugendstil to 1960s modern. Claus and Kaan's two built interventions play within these rules of tightly-packed four-or five-storey facades. Both their scheme on Haarlemmerstraat and that around the corner on Binnenwieringerstraat stretch metal and glass and brick across stacked interiors. The resultingly taut elevations have a planarity which allows them to merge into the city's general fabric.

Both built works - there is a third, as yet unrealised, two blocks away - insert a new structure into the additive street frontage and rehabilitate an adjacent house. Thus both projects deal with their streetscapes but also are programmatically linked to a neighbour, intertwined or locked into the urban mass. The Haarlemmerstraat facade clearly indicates this. At street level, a shop spreads from the new construction to pop up inside the old. Above it, two layers of brick and horizontal strip window set up a counterpoint with the surrounding vertical openings before a glazed cube emerges from the parapet, a studio against the sky. With their brownish hue, the intermediary panels have a stylish anonymity. But their horizontal fenestration has a similar logic - maximal light - to the vertical pattern next door. It is the boxed attic above which attracts attention. It projects slightly forward and, in cranked proximity, sits away from its sibling gable. In scale and materiality, it instigates a diagonal rapport with the refurbished shopfront below.

The composition is furthermore asymmetric due to its entrance at one side. This tunnel or extruded void serves not only the Haarlemmerstraat apartments but also a pre-existing fire escape from the hotel next door. Entry to the flats is from a small rear courtyard, facing south and overlooked by yet another building with a projecting garden apartment - renovated by Claus and Kaan to the east. An external stair wraps around to pierce the now timber-clad back facade and enter the new segment. There an internal dogleg stair staggers back and forth to one-bedroom units in the new segment and studios in the old before giving access to the three-bedroom duplex.

The three apartments on Binnenwieringerstraat employ a more radical planning strategy. There the older structure is gutted to allow single loft-type living spaces on each floor. The new structure then contains the more private and technical functions: vertical circulation, storage, one bath and one bedroom per floor. It's an urban life support system and the architects have delighted in expressing their surgical implant externally.

Almost flush with the street elevation is a new screen of three large sheets of glass. It's shocking and seductive, with fluorescent tubes (concealed behind the metal section) illuminating the interior wall of vivid yellow paint. The surface of each glazing panel is divided into translucent and transparent areas so that the public cannot quite read the circular stairs behind. Finally, the glass folds inwards on top so that this sheer and rather cinematic foyer is also washed in zenithal light.

Claus and Kaan have realised these small increments of affordable housing with a kind of knowing relish. Their intervention on Binnenwieringerstraat-which, unlike its colleague, entailed demolition - achieves a particular finesse geometrically. Like the fin-de-siecle Maison Coilliot in Lille by Hector Guimard, it sits on a rectilinear site made trapezoidal by the slice of its street. There ensues a game whereby the plan and inner wall are orthogonal but the elevation lies askew. This in fact is typical of Amsterdam where there are many discrepancies between the street facades and projecting mechanisms. Notice, for example, the hoist in the older gable at right angles to the yellow surface.

Back at Haarlemmerstraat a tenant was asked to rate that scheme. He enjoyed it very much, but had never thought of it as architecture. Perhaps this is the greatest compliment to Claus and Kaan, to have fitted their contemporary apartment types so snugly into the texture of the city.