Winchester College

Winchester College’s new Sixth Form boarding houses form a sensitive addition to the historic 640-year-old campus, providing modern accommodation for boarders and day pupils while reflecting the College’s collegiate character.

Designed by Stanton Williams, the two new buildings combine a domestic architectural character with central courtyards, communal spaces, and brick façades that complement the surrounding historic buildings. IG Masonry Support was appointed by Gilbert-Ash to provide a coordinated masonry support and prefabricated brick slip system package for the development, supporting the complex brick façade while helping to achieve the project’s high architectural and sustainability ambitions, including its Passivhaus design approach.

The architectural vision for Winchester College’s new boarding houses called for intricate brickwork detailing that would be difficult and time-consuming to achieve through traditional construction methods, requiring specialist masonry support expertise from an early stage.

Brick Mullions
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Brick mullions (vertical brick piers separating windows and openings) featured throughout the façade as a distinctive architectural detail, predominantly between window frames. Each mullion presented a demanding structural challenge: they had to accommodate both vertical load transfer and lateral restraint at a single interface. This was further complicated by the elements above and below it, each with different load-bearing characteristics. Above, Stone Lintels bore onto the mullions intermittently across the bay rather than continuously, creating concentrated point loads that each mullion had to accept and carry downward. Below, Brick Slip Cills were designed to carry no load at all, so the load path had to be diverted around them and through the mullion instead. Brick Slip Lintels added a further interface to coordinate.

Space was also tight. Any restraint had to fit within a restricted zone between the mullion and the window frame, and remain effective despite anticipated differential movement between the CLT frame and the masonry, all without compromising the load path or making installation on-site more difficult.

Section View
IG Masonry Support Technical Drawing Brick Mullion Restraint System

Brick Slip Cills
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Prefabricated Brick Slip Cills were needed beneath a number of windows across the façade, but no two locations were quite the same. Cill positions shifted with the bay layout and mullion arrangement, so a single repeated unit could not be used and producing too many bespoke units risked undermining buildability and consistency onsite. The challenge was finding a way to cover the full range of conditions without losing the benefits of standardisation.

The cills also presented a structural challenge. Although they were designed to carry no load, with load passing instead through the brick mullions, the mullion restraint had to pass through the cill. Restraint load would therefore need to travel through the cill and into the brickwork below without interrupting the load path. In addition, any visible fixing or disruption to the coursing and bond would compromise the architectural intent of a continuous brick façade.

Brick Bonds & Handmade Specials
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The façade combined a complex mix of brick bonds and profiles, including Flemish bond, half-lap bond, stretcher bond and staggered sailor bond. Brick mullions incorporated bull-nose bricks of varying depths, adding further complexity to setting out and coordination across the façade.

The use of handmade brick specials by York Handmade Brick Company introduced additional variability, as individual bricks differed in shape and size. This had to be reconciled against the need for surrounding
brickwork, cills, mullions and lintels to align precisely and preserve the intended architectural detailing – requiring close coordination between the specialist brick supplier, architect and site team throughout design.

Elevation View
South Elevation – Varying Brick Bonds

IG Masonry Support worked in close partnership with the project team, providing the technical expertise and bespoke system coordination needed to integrate prefabricated brick slip solutions and help bring the complex, visually striking architectural vision to life.

Brick Mullions

IG Masonry Support developed an integrated restraint system that worked alongside its prefabricated Brick Slip Cill assemblies and the Brick Slip Lintels and Stone Lintels above.

The restraint system was designed to fit within the reduced zone between the mullion and window frame and allowed for vertical adjustment and a hand-set installation approach, while maintaining lateral restraint back to the CLT frame. It also accommodated anticipated frame settlement through controlled vertical movement, without compromising that restraint.

A bespoke bolt box, concealed within the cill, connected the mullion to the cill. This transferred restraint loads from the lintel through the mullion and cill, and into the brickwork spandrels and foundations.

Brick Slip Cills
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A modular Brick Slip Cill comprising left, middle and right variants was developed around a standardised core detail, allowing it to be used consistently across the project regardless of bay position. This gave the contractor a repeatable, familiar installation sequence at every window, reducing both installation time and the risk of error on-site, while still accommodating the full range of conditions across the façade.

A bespoke bolt box, concealed within the cill, enabled the transfer of restraint load from the mullion restraint system through the internal structure of the cill and down into the brickwork below, maintaining the verified load path established through the mullion and lintel design. To preserve a consistent finish, the bolt box was designed to be infilled with handset brickwork, allowing it to align precisely with the surrounding brickwork in both bond and coursing – ensuring the load-transferring element remained structurally active while disappearing visually into the façade.

Brick Bonds & Handmade Specials
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IG Masonry Support worked closely with the architect, York Handmade Brick Company and the site team to integrate each brickwork condition with the masonry support and brick slip systems, ensuring the varied bonds, mullion profiles and specials could be accommodated without compromising the architectural intent. Support and cill details were developed to suit the varying depths of the bull-nose mullions while maintaining consistent alignment.

For the handmade specials, IG Masonry Support reviewed samples with York Handmade Brick Company to confirm profiles, ensuring accurate integration with the surrounding brickwork. Detailed setting out coordinated cills, mullions, lintels and adjacent brickwork, allowing the bonds to transition cleanly and coursing to remain consistent throughout – avoiding visible inconsistencies in the finished façade.

Winchester College Case Study Brochure
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