Conserving the Hilda Besse Building

After surviving for 50 years predominantly as originally designed and built, the Grade II listed Hilda Besse Building at St Antony’s College, Oxford, is being refurbished.

The south elevation, which is due to undergo re-landscaping once the temporary decant facilities have been removed.

1 Introduction
2 Assessing significance
3 Conservation philosophy
4 Inclusive access
5 Related articles on Designing Buildings Wiki

Introduction

St Antony’s College was founded in 1950 following the donation of £2 million from businessman Sir Antonin Besse. Named after his wife, the Hilda Besse Building is the only realised element from a 1960 master plan drawn up by HKPA (Howell Killick Partridge and Amis) for the fledgling college, which decided to prioritise the creation of a large hall and common rooms in order to bring students together.

After nearly 50 years of use, the operational weaknesses of the Hilda Besse Building in the 21st century were apparent. The kitchen and servery configuration was inefficient; the fellows’ dining room was too small; access was not inclusive; and the building was generally looking tired. Purcell has been leading the refurbishment of the building with a scheme to improve facilities, accessibility and overall appearance.

Assessing significance

The Hilda Besse Building is Grade II listed. Scholars in the field of 20th-century architecture have even suggested it ought to be upgraded to Grade II*. Traditionally, evaluating the significance of a listed building primarily takes stock of its phasing, and the integrity of each phase, rarity, notable associations and a host of other factors. However, this approach simply does not best fit a single-phase construction realising the design of one practice. The Hilda Besse Building survives predominantly as originally designed and built, with minimal intervention. In preparing proposals, to simply say that the whole building was equally significant would not be at all helpful. We consequently needed to find a new angle to understand where there was capacity to enact change throughout the building so that it could continue to perform its intended role as the heart of the college.

We ultimately broke down the spatial hierarchy across the building into three tiers:

Primary spaces, such as the dining and common rooms, the status of which it was most important to retain and enhance so that they can continue to perform their original roles.
Secondary spaces, such as the entrance lobby and main circulation routes, which incorporate characteristic materials and design features but whose value was not inherently linked with a traditional college use.
Tertiary spaces: ancillary areas such as stores and the kitchen, which are utilitarian and support the function of the primary and secondary spaces.

Significant themes and features across the building that tie its spaces together included the pervasive natural light and materials palette, particularly the use of exposed concrete.

Conservation philosophy

The Hilda Besse Building has been the physical and ceremonial heart of St Antony’s since it was completed in 1970. However, it had not undergone any notable upgrade during its 50 years. The concrete exterior, which had gleamed so brightly when the building was first opened, had become darkened and stained: the blight of so many 20th-century buildings. Internally, its spaces performed inefficiently, and inclusive access was poor.

It was imperative that the building could maintain its original function. This ongoing use of college and university buildings in Oxford is a key component of what makes them significant. While there were obvious opportunities to improve the building – chipping away decades of varnish to expose the engineering brick floor, for example – several issues required more detailed options appraisals and applying lessons learnt from other projects.

The windows were a particular concern as the immense size of the single-glazed panes emitted considerable heat. Purcell had previously dealt with similar challenges at Christ Church, where we oversaw the refurbishment of Powell and Moya’s Grade II* Blue Boar Quad. In this instance, we were able to justify the replacement of the failing original windows with new double-glazed units which, with other interventions, improved the building’s sustainability but still respected the original design intent. After lengthy philosophical debates with various stakeholders and consultation with manufacturers, it became apparent that a similar approach at the Hilda Besse Building would not be possible. The windows were so large that replacement with a double-glazed unit would require a thicker frame to support the additional weight, which was not a comfortable fit with the building’s architectural value. To protect the significance of the building, it was ultimately concluded that the glazing would be retained and sustainability improvements sought elsewhere.

Externally, the envelope of the building had retained its distinctive ‘eyelid’ windows and was still entirely recognisable as a HKPA design, but the exposed concrete had become heavily stained and was spalling in places. Unlike its medieval peers, St Antony’s College is not hidden away behind gates and the Hilda Besse Building is readily glimpsed from the road, so its deteriorating exterior was becoming a detracting feature in what is otherwise a strikingly framed view of the building.

The ambition for the external repairs was to match the existing surface as closely as possible such that the repairs would be apparent only from up close. It was recognised that an honest, SPAB-style repair that was plain to see would only detract from the unity of the building as a whole. The original surface would be difficult to replicate entirely faithfully as the concrete blocks were originally cast face down within a form and then removed before being fully cured, at which time the surface was washed down to expose the rich aggregate. The aesthetic of this has been re-created where the concrete had deteriorated using different mortars and aggregate applied by hand to the surface. The project team considered the use of a sealant but quickly concluded that a quality repair would considerably outlive the lifespan of any sealant and such exercise was consequently needless.

Prior to repairs, surface cleaning proceeded relatively simply using a Doff system or, where areas of the internal concrete are too finely cast to endure the heat of the steam, simply washing down with a light detergent. Photographs from the 1970s showing the building when it was new reveal a bright exterior: the result of freshly-cast concrete and gleaming aggregate. While the internal alterations will no doubt vastly improve the usability of the building, it is perhaps safe to say that its external overhaul will draw equal, if not more, exclaim.

Inclusive access

One of the principal challenges with the Hilda Besse Building became evident even before fully entering it: to facilitate step-free access, a temporary ramp had long been positioned over one half of the entrance lobby steps. Further to this, the distinctive plinth on which the building sits prohibits direct step-free circumnavigation around from one side of the campus to the other. Given the aspiration to future-proof the building as the heart of the college, it was a critical part of the project brief to address the building’s shortcomings when it came to inclusive access and connectivity.

The plinth and its engineering brick construction ultimately facilitated a smart design solution to this issue. New ramps replaced the steps within the entrance lobbies on either side of the building, detailed using the same engineering brick finish, and the external plinth was extended outwards on the south side of the building to create a level path from one side of the college to the other. This was also extended on the east side of the building to create a new ramp with neatly detailed steps that reads as an entirely comfortable evolution of HKPA’s original design.

The original HKPA master plan was never fully realised. The college became an eclectic mix of former convent buildings, the Hilda Bess Building being one realised feature from a much wider master plan, and a series of later buildings. Unlike the all-encompassing and unified sense of place at St Catherine’s College, a near contemporary of St Antony’s, the Hilda Besse Building sits within a space that is almost accidental. With the improvements to connectivity around the building, the project will also rationalise the landscape: creating a recognisable ‘Oxford quad’ but retaining the informality which St Antony’s celebrates.

The refurbishment of the building has served as a reminder of the importance of tailoring a bespoke conservation philosophy: seeking inspiration from similar projects and the building itself but accepting that there is no one-size-fits-all solution. Once complete, this will still be the same building known and loved by the college, only smarter, more efficient and fit for at least another 50 years.

This article originally appeared in Context 166, published by the Institute of Historic Building Conservation (IHBC) in November 2020. It was written by Hettie Dix, a senior heritage consultant at Purcell, based in Oxford.

--Institute of Historic Building Conservation