Open and shut case
On a tight site, two major projects by Dinwiddie MacLaren Architects have been reshaping Hornsby House School in Balham, south-west London. The Nightingale Building, built along the eastern edge of the site, opened in early 2002. The latest classroom building is along the southern site edge, on Hearnville Road. With the demolition of an earlier building, a modest-sized playground is now available between these additions and the Victorian main building. (The school has shared use of a playing field nearby. ) Hornsby House is a private, 270-pupil, primary school, with a small nursery and pre-school unit for three and four year olds.
Founded in 1988, and focused at that time on children with special needs, it moved to this site in 1993 and has largely become a general primary school, though retaining some of its original care agenda.
Demands for security arise here, as they do for the other schools, but here the response is more fortress-like. On Ravenslea Road a new perimeter brick wall maintains the secure site boundary of this gated school community. The only break is a glazed stair tower, approached through somewhat forbidding galvanised fencing. (This is just a visitors' entrance; the pupils' entrance is elsewhere on the perimeter. ) With the remainder of the new building tight behind this wall, the south-side ground floor is cut off from views and so is largely lined with stores and WCs.
The main office spaces and library open to the north on to the playground.
The music room by contrast makes use of this southerly enclosure for acoustic protection, with windows only opening immediately onto the boundary wall as it swings round to form a vehicle entrance - nothing on the playground side. Double walls provide acoustic separation from the outdoors and from the rest of the building.
Practice rooms are accessed from the lobby, which also assists acoustic separation.
On the first floor the feel changes. The space is accommodated within a 9m span, barrel-vaulted roof, with its springing points aligning with adjacent eaves of the Victorian school buildings. This first floor is fully glazed and shaded at either end. Its two central classrooms borrow light from a northern fully glazed gallery, supplemented by sun pipes at the ridge. Southerly windows are restricted in size.
Also at the ridge of each first-floor room are Monodraught Windcatchers, internally subdivided both to admit wind for ventilation and to facilitate passive stack ventilation. (The ground floor is ventilated conventionally via windows, except for supplementary mechanical ventilation in the library. ) The open areas of the windcatchers are controlled automatically via dampers, based on temperature and CO 2 sensing, with manual override. Their setup is predominantly for summer ventilation, including at night-time, with a trickle ventilation function in the heating season.
The envelope is deliberately low-maintenance, a combination of matching stock bricks and the terne-coated steel to the barrel vault.
While perimeter architecture sends out the message of security to visitors, rather than welcoming them with open arms, students and staff, at least, are provided with a sense of openness. In particular, the extensive northerly glazing both provides generous daylighting and connects the new block to the rest of the school.