Domestic spiral and cylindrical stairs

The decorative and sculptural quality of spiral stairs is no doubt the reason that so many kits or standard spirals in concrete, steel or timber are now available. A contributing factor is the ease with which computer aids can speed designing such features to fulfil site requirements and to meet the onerous restrictions of the current Building Codes as given in Chapter 10. It is sufficient at this stage to confirm that 1 800 mm diameter is the minimum drum for spirals in private houses. This dimension assumes a clear headroom of 2 000 mm. The diameter can be reduced to 1 400 mm for a stair intended for occasional use with access to one room or a balcony etc. The normal diameters of 1 800 mm show no saving in well dimensions below minimal dog-legs

Scallop form to give space for furniture removal

wall to well

Scallop form to give space for furniture removal wall to well

900 but 1000 preferable

Figure 4.6 Scissors stair with scalloped spine walls

Figure 4.7 Domestic spiral stair, Highbury Terrace Mews, 1971, Architect: Peter Collymore (courtesy of Bill Toomey)

and winders. There is, however, the visual consideration where the spiral has a greater advantage (Figure 4.7) and the fact that the design cannot be compromised by boxing in for understairs cupboards or with lavatories for pygmies. The design problem has been greatly eased by standardized components and particularly those with threshold arrangements at each access point. Makers offer a range of riser proportions so that quarter

Figure 4.7 Domestic spiral stair, Highbury Terrace Mews, 1971, Architect: Peter Collymore (courtesy of Bill Toomey)

Spiral Stairs
Figure 4.8 Landing locations

First floor

Figure 4.9a Shrublands, Chalfont St Giles, 1935, Architects: Mendelsohn and Chermayeff: First floor plan

First floor

Figure 4.9a Shrublands, Chalfont St Giles, 1935, Architects: Mendelsohn and Chermayeff: First floor plan

Clockwise

Ground floor circulation to vestibule and stairs

Clockwise

Ground floor circulation to vestibule and stairs

Figure 4.9b Shrublands, Chalfont St Giles: Ground floor plan landings can be neatly stacked one over the other to cover a choice of storey heights. Differing heights can be accomplished by adjusting landing locations (Figure 4.8). The easiest answer is to employ an open quadrant facing the

Figure 4.9c Shrublands, Chalfont St Giles: View of ground floor flight

main circulation that can be opened or closed according to the number of treads needed as this will produce a more consistent solution. Other methods involve turning the landing segment quarter by quarter where differences in storey height occur. The quarter landing shape makes for an easy transition from floor space to spiral geometry.

Cylindrical stairs have a more spacious effect whether placed free standing or within the shell of an enclosing drum. Contrasting the curved and straight line is a feature of early modernism. Mendelsohn and Chermayeff created a seminal house of the 1930s at Shrublands, Chalfont St Giles, where the swept line of the stair is placed at the crucial break in the plan (Figure 4.9). The elegance of the solution is extended

into the detail of the swept platform at the base and to the helical handrail that terminates the balustrade. Another example of this genre is the work of Raymond McGrath at St Anne's Hill, Chertsey (Figure 4.10), where a segmental vestibule embraces a cantilever cylindrical stair. Such exercises in imagination raise expectations for the scenario at first floor. The Mendelsohn theme creates a fine hall with two-way views as well as access to the master suite and guest wing in descending order. McGrath's dramatic layout leads to the circular master bedroom that is the hub of the house, set in an eighteenth-century landscape gar-den.3 Both these large houses were twin-stair designs, one for the master and one for the servants; the secondary stairs were mundane affairs tucked away in the corner of the plan. The social mores of the time dictated these concepts, though the circumstances at St Anne's Hill caused special conditions

Figure 4.10b St Anne's Hill, Chertsey: Hall and stairs

House Plans 1937
Figure 4.10a St Anne's Hill, Chertsey, 1937, Architect: Raymond McGrath: Ground floor plan

whereby the master bedroom had totally separate circulation from the servants. The origins for white concrete cylindrical stairs must surely be the creations of Le Corbusier and Pierre Jeanneret in their heroic period of the 1920s. The freestanding setting within the Villa Savoye raises the stair into the vantage point, with slots cut in the drum wall to reveal the building interior (Figure 4.11). The famous ramp is the ultimate pivotal zone which allows the whole space to unfold from ground floor to roof terrace. The structural role of stair drum or ramp framing is used to the full. Erno Goldfinger borrowed the same theme for the half circular flight at Willow Road. Here the reinforced concrete floor slabs run cross wall to cross wall with an intermediate support on the reinforced concrete stair drum that is placed central to the depth of the plan (Figure 4.12).

4.2.4 Modernism and domestic stairs

The concept of the open stair within the open plan is the hallmark of the Corbusian ideal. The initial designs for the Dom-Ino Skeletal House (circa 1914-15) demon-

Ramp Architecture Corbusier
Figure 4.11 Villa Savoye, 1929-31, Architects: Le Corbusier and Pierre Jeaneret. Stair and ramp
Figure 4.12 Use of stair walls in structure, Willow Road, London, NW3, 1937, Architect: Erno Goldfinger

strated a framed structure with reinforced concrete dog-leg stairs spanning between cantilevered landing slabs (Figure 4.13a).4 The development of this concept through the designs for Maison Citrohan arranged the stairs as direct flights to save frontage, with the final version built at the Weissenhof exhibition, Stuttgart, in 1927 (Figures 4.13 b and 4.13c). The significance of these layouts is the way that dining and living areas are deployed as circulation zones without separation into rooms and stairhalls.

The modernist device is to use the stair as a freely-placed feature to liberate the spacial development of the interior. An example of this doctrine is the remodelling of a pair of houses in St Leonard's Terrace, Chelsea, by Richard Rogers Partnership. This design opens the traditional vertical box-like London home into a series of large horizontal spaces.

The major element is a double-height apartment at first floor with a projecting mezzanine forming a sleeping balcony. Access within the apartment is made via a staircase running on the diagonal (Figure 4.14). The use of the longer dimension for ascent increases the sense of space and enhances the fine proportions. The backdrop is a well-fenestrated façade comprising twelve windows. The

Dom Ino House
Figure 4.13a Dom-Ino Skeletal House: First sketch (circa 1914-15)
Half Landing Staircase

Figure 4.13b Fr«me for built ex«mple «t Stuttg«rt, 1927, Architects: Le Corbusier «nd Pierre Je«nneret (from L'Architecture Vivante)

Up

I

1

3

I

/

Ground floor to 2nd floor from ground floor

"1U1

Lounge

First floor up to 3rd floor bedrooms and roof terrace

■n up to 3rd floor bedrooms and roof terrace

Second floor

Figure 4.13c Dom-Ino Skeletal House: Plan arrangements conversion has a well-contrived subdivision between staff facilities at basement level, the grandparents' flat at ground floor and the children's territory zone at the upper levels, with the parental zone of the grand apartment sandwiched between. The principal vertical circulation, top to bottom, is a steel spiral stair case which rises in a self-contained well to bypass the principal living area. The subdivision allows for multiple use in the reverse order to the Goldfinger home which eventually accommodated three generations of the family floor by floor — the youngest family in the garden basement flat, Ernö and Ursula at ground

Dogleg Staircase
Figure 4.14 Rogers' Apartment, St Leonard's Terrace, London, 1985, Architects: Richard Rogers Partnership. General view of 2-storey volume with stair on diagonal

and first floor, whilst Grandma Goldfinger ruled the second floor.

The Hopkins house in Downshire Hill also shares the spacious quality of open planning, with the stair sited within the middle zone of a nine compartment plan. The planning grid is based upon a minimal steel framing module of 2 x 4 m. The core, that includes bathrooms and the spiral stair, is 2 m wide while the principal rooms towards the garden and street occupy a double bay of 4 m each (Figure 4.15a). The steel spiral forms a skeletal structure in a minimal tube within the main circulation space (Figure 4.15 b). Flexibility in the layout allows partitions to be added as family requirements change, with the garden level split into flatlets when the children are older.

The thematic response can best be seen in the cantilever spiral that is at the heart of the Jencks Victorian villa. Here each tread fits one to the other like the spiralling of a conch shell. The depth and height are signified by a mosaic telling of the underworld set in the basement floor and by the cascading light from the domical 'eye' to the sky. Each step is numerated to tell of the ascent, the whole movement of the flight being captured by finely made sinuous handrailing. The oval plan is masterly, with spreadeagle treads that lead off into the landings (Figure 4.16).

Michael Hopkins House Plan
Figure 4.15a Hopkins House, Downshire Hill, London, 1976, Architects: Michael and Patty Hopkins: Layout plan

4.2.5 Ladders and steps

Ladders and steps are special forms of steeper design; they are permitted for particular purposes, e.g. occasional access to roof spaces or service rooms. Loft ladders are generally collapsible or operate with a trapdoor mechanism. The space limitations are the transverse run of the equipment within the roof for the extending pattern and the area needed when the ladder is erected, both the footspace and the girth needed to walk around the obstruction. Folding scissors ladders exist but these are not as stable as telescopic ladders.

Fixed steps have the advantage that access is permanent, with guard rails at the upper level; in addition non-mechanical items can fit site dimensions more easily. The summary of the British Regulations for long ladders is given in Figure 4.17. Half steps are also permitted, providing only one room is served, and are more comfortable to the tread than narrow rungs. In principle, ladders and half steps allow angles of ascent of between 60° and 70°. The construction of the latter can be made in pre-cast concrete, steel or

Figure 4.16 Stairs at the Jencks House, Ladbrooke, London, 1986, joint designer: Terry Farrell & Co.

Figure 4.15b Hopkins House, Downshire Hill, London: General view of spiral stairs at core of plan

Figure 4.16 Stairs at the Jencks House, Ladbrooke, London, 1986, joint designer: Terry Farrell & Co.

Maintenance Access Ladder Principles
Figure 4.17 Loft ladder principles

timber; standard timber flights can be obtained from Denmark and Italy (Figure 4.18). For Building Regulations see Figure 10.1 d.

4.2.6 Other forms

Three-turn forms take up more space than dog-leg or spirals. However, the openness of the central well can enhance the natural lighting given by the upper landing windows or roof lights. One source of these ideas is the vertical cores that served Ottoman domestic architecture. The structures are generally timber post and beam with brick infilling. The treads are often corbelled stone, braced by continuous newel framing. Wreathed handrails are replaced by panels of slats with individual handrails fitted between the verticals (Figure 4.19).

Cylindrical Stairs
Figure 4.18 Proprietary ladder steps (courtesy of Space Saver Stairs (UK) Ltd)
Figure 4.19 Three-turn stairs: Ottoman Merchants House, Cairo (circa 1500)

4.2.7 Elevational considerations

Central siting for stairs or locations placed by internal walls provide no elevational problems apart from the provision of adequate windows to light the steps. Flights placed against the external wall look dramatic behind extensive glazing but make for difficulty with internal window cleaning (see Figure 4.9 to visualize the problems). Windows that step up with the flight may be the answer but often appear awkward externally. The vertical or thermometer window is the other dubious invention (Figure 4.20).

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