‘It is so moral, so British, to claim the disk roof is at that angle for PVs not for the beauty of it.’ So said Charles Jencks co-founder of Maggies’ to Ted Cullinan, the architect of the latest Maggie's Centre in Newcastle. Jencks has the trick of sounding more authoritative on the work of Cullinan than does Cullinan himself.

But as always he has put his finger on something. The seduction of this solar collector of a building, this enfolding L of warmth and hospitality for those affected by cancer, is not in the passive solar gain but in the environment it creates. It is not in the 15˚ roof angle but in its lilt. It reads as a happy building with the uplift of the warm glulams under the slim roof profile.

In the early sketches, and Cullinan’s lectures, this building comes across as complex and exuberant. But it is neither of these. It is set out on a rational and explicit 3.6m x 3.6m grid, expressed on the ceiling plane. The exercise room exhibits the ‘naked’ grid explains Cullinan. The exposed in situ slab is four of the squares, in the next door room the dimensions are just one module. Where, occasionally, a partition is off the main grid it is treated more as piece of furniture. Affixed into the square coffers are installations of intersecting timber, the grid in miniature, and washed with light behind all but the centre square. There is a nod to Japan in these and Jencks detects more than a little Arts and Crafts. Facing out on the Freeman Hospital’s Northern Centre for Cancer Care stripes of Corten panels match the grid, offset by galvanised steel verticals that reach up to support the handrails.

Jencks points to the underground nature of the building as typical Cullinan, although Cullinan himself gently reminds us that it is actually the other way round; the building is set firmly at ground level and the soil pulled up around it, adding extra insulation to the north and east (clerestorey windows just peering over the top) and enclosing the courtyard to keep out the worst of the wind. Equally typical of Cullinan are the angular windows which dive down into the berm at the centre of the elevations.

Inside Maggie’s vice chair Marcia Blakenham explains the importance of a quiet space for those coming into the centre for the first time (it normally takes three goes for someone to come in she says). An open office at the entrance gives members of staff the chance to keep an eye out for those who might need a friendly hello. The kettle and the kitchen table still take pride of place but are a little less immediately present from the entrance than in some Maggies’, instead the first space is the library with its embedded sofas and wide window sills, then the open stairs with reading alcoves. Above them all the glulams curve with a happy flick towards the roof terraces, and the sky.