Mill Hide, Royston, Hertfordshire

2025 RIBA East Award 

House
Poulson Architecture for Tim and Elizabeth Poulson
Contract value: Confidential
GIA: 507 m²

Mill Hide has surprisingly high sustainability standards – perhaps not what one might expect from a robustly modern villa whose geometries are an interpretation of the iconic 16th-century Villa Rotonda near Vicenza, famously designed by Andrea Palladio. 

But the client/architect demonstrated as much passion for designing in sustainability as he did for all other aspects of the design. The house benefits from good airtightness; insulation above Building Regulations standards; a single air-source heat pump servicing the whole house and cleverly screened behind cladding; a mechanical ventilation with heat recovery (MVHR) system throughout; spacious plant rooms for future flexibility; thin film photovoltaics; and lots of passive solar shading. The simple geometry, with the house square in plan, creates a beneficial form factor for all these measures.

The site is carefully located on the edge of a magical RSPB nature reserve. The ambition was to avoid interfering with this natural setting beyond the boundaries of the villa, and to enjoy the views into it from each orientation of the house. The first geometry visitors experience is the sweep of the semicircular drive, slightly raised above the marshland. 

The house sits modestly on the site, surrounded by the natural landscape but with cut lawn reaching up to the colonnade on the southeast and southwest faces. The colonnade is made of small triangular columns set at 1.5m intervals, except for the wider central bay. 

These are elegant and appear very thin as you pass through the space – a real piece of magic that belies the tough surface material. As well as providing passive shading, the colonnades break the overall form and allow light to modulate the massing. A contrasting but similar effect is created at night from the large windows within.

Corten weathering steel is used as a rural material and was made locally with workshop teams known by the architect, who was also the main contractor, client, owner and occupier. All the steel panel joints are totally minimal so the material can rust together over time, and there are no visible fixings as all the components slide to a hidden frame. It is all very ingenious and yet its simplicity hides the sophistication and control of the whole construction and composition. 

All the rooms of the house are set around the central atrium, which has a magnificent motorised rooflight that opens up the sky. It is breathtaking, minimalist and inspired by the light artist James Turrell. 

The sequence of living rooms from the kitchen are carefully subdivided by joinery walls or shelving to provide composed and comfortable liveable spaces. The subdivision aligns with the full-height glazed doors that can disappear within the wall to open the rooms entirely to the colonnade. This is all part of the meticulous detailing throughout the house.

This is a large house for two occupants. However, it is fully accessible and flexible, and could easily be retrofitted to have at least five bedrooms in the northern ‘sleeping’ wing, for future generations or owners. Most importantly, it is very elegant, skilfully composed and beautifully detailed – while using less operational energy that the RIBA 2030 Climate Challenge target.

View all of our East winners here, and all our RIBA UK Award winners here.

View the full RIBA UK Awards 2025 process.

RIBA UK Awards 2025 sponsored by Autodesk, EH Smith, Equitone and VELUX