“Most of the blocks planned on a north to south axis (the outlook from which is either to the east or the west) have flats on either side of a central corridor. This is an economical solution as it reduces the number of lifts which need to be provided in these buildings.”
Chamberlin, Powell & Bon, Architects “Barbican Redevelopment” April 1959
Terraces on a north-south axis means blocks like Seddon, Mountjoy and Gilbert, where the length of the terrace is on a north to south line. Terrace blocks which run north to south have windows on the long sides which face east or west. Sunlight is reasonably equally split between the two sides. Windows on the east side of the terrace get sun in the mornings; and those on the west side get sun in the afternoons. So the architects decided it was reasonable to have some flats facing exclusively east, and some flats facing exclusively west. (This couldn’t be done with the flats on an east-west axis, because most of the sunshine would go to the south facing flats, and little or none to to the north facing flats.) So, with the exception of Willoughby House, north-south terraces were designed with a central corridor on each floor, with flats off it on each side, facing either east or west. Lifts and stairs are at either end of the central corridor.
The majority of the dwellings in the centre of these blocks are of the 3-room type, except on the upper floors where they are penthouses with five rooms and a roof terrace.
The general layout is the same in all these flats. The living room and the bedroom are side by side at the front; the kitchen takes a chunk out of the back of the living area (leaving a dining area on one side); the bathroom and WC are behind the bedroom. In the penthouse maisonettes, part of the living room is two storeys high, with a staircase to a gallery where there is another bedroom and a study.
It is not actually true to say that all flats with central corridors are in blocks running north-south. It seems to me that Ben Jonson House is more east to west than it is north to south – it looks to be roughly parallel with Defoe and Speed Houses nearby in the south. But unlike those houses, the Ben Johnson flats are all off long central corridors. And John Trundle Court and Bretton House seem to run north-south and yet they have studio flats round individual lifts and stairs.