St. Mary's Outpatients Extension

A single-storey outpatients extension to a working district hospital, delivered in fourteen weeks of design time against a construction programme that could not be allowed to disturb clinical operations. The site sat hard against a live circulation corridor, with pharmacy deliveries, patient flow, and ambulance access all passing within metres of the building line. Every design decision had to be traced back to the trust’s own operational rules before it was worth drawing.

The Revit model carried two overlay systems from day one. An infection-control overlay marked every surface in clean-zone and dirty-zone terms, and the materials schedule was written against those zones — no open-jointed linings in treatment rooms, no horizontal ledges above hand-wash height in the clean corridor. A separate security overlay governed sightlines, door control, and the handling of the clinic’s drug store, which had to remain visible from the reception desk and lockable to a specific BS standard.

Phasing a live site

Because the hospital never closed, the construction phasing was as important as the geometry. The model was phased into four works packages — enabling works, envelope, fit-out, and clinical handover — and the workset for the live corridor was locked at the start of every week. No demolition of the existing plant garden wall was allowed on the model until the temporary protection order was in. In Navisworks, the programme’s four-stage sequence was run as a timeline, and the site team used the output to sequence the concrete works so that patient access was maintained behind a hoarding line we had drawn, and they agreed to, weeks earlier.

Solibri rule checks

Accessibility and egress were never left to the drawing board. The model was run through Solibri Office against a rule set written for the trust: door widths at every point in the patient route, turning circles in the waiting area, gradient and landing dimensions on the approach ramp, and egress path lengths from every consulting room. Any rule failure was fixed in the model before it ever appeared on a sheet — the audit report, exported and signed off at each issue, became part of the design record.

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The portal frame was detailed to fabrication level in the model, with the welded connections modelled true rather than as generic members, so the steel fabricator cut their drawings from our IFC with only a handful of questions. At handover the extension was handed over with a structured asset register, room data sheets, and the operation-and-maintenance model, and the clinical team moved in on the agreed date without a single delay caused by the design office.