Improving Environmental Performance Within a Historic Interior
The Pitt Building is a prominent civic and academic landmark on Trumpington Street in central Cambridge. Completed in 1833, the building holds an important place in the city’s publishing and university history and today operates as a high‑profile conference and events venue. Its interior spaces are characterised by generous proportions, stone detailing and a clear ceremonial sequence of arrival.
As part of a wider refurbishment led by Allies and Morrison, IQ Projects was appointed to design and deliver a series of specialist internal glazing interventions. The primary objective was to improve environmental performance, accessibility and circulation at key entrance points while preserving the architectural clarity and historic fabric of the interior.
Balancing Heritage Sensitivity and Contemporary Use
Working within a highly significant nineteenth‑century building required a restrained and reversible design approach. The Pitt Building is subject to strict heritage controls, meaning that any new interventions needed to be visually recessive, structurally independent and sympathetic to existing materials and proportions.
At the same time, the building’s current use as a public venue places considerable demands on comfort, durability and operational efficiency. The original entrance sequence suffered from heat loss and draughts, but conventional framed lobbies or partitioned enclosures would have compromised sightlines and diminished the sense of arrival. The challenge was therefore to introduce environmental buffering without subdividing space or obscuring original architectural features.
A Double‑Height Frameless Glass Draft Lobby
IQ Projects responded by designing a double‑height, three‑sided frameless glass draft lobby positioned immediately inside the main entrance. Conceived as a transparent internal volume, the lobby acts as a thermal and air‑control buffer while allowing the original stonework and spatial proportions to remain fully visible.
The enclosure is formed from laminated structural glass panels connected using glass‑to‑glass silicone joints, eliminating the need for visible framing. The side elevations are fixed, while the principal elevation incorporates a generous double‑height pivot door to accommodate high levels of footfall during events and conferences.
All glass panels were carefully notched and set out to work around existing stone elements, ensuring that the historic fabric was neither concealed nor disturbed. Hardware and fittings were detailed to remain as discreet as possible, allowing the glazing to read as a light, contemporary insertion rather than a dominant architectural object.
Secondary Lobby and Automated Circulation Control
To further improve environmental regulation and circulation flow, a second internal frameless glass lobby was introduced deeper within the building. This enclosure combines fixed structural glass panels with an automated frameless sliding door on the primary access elevation.
The sliding door system is top‑hung, with a minimal floor guide to maintain a flush threshold and avoid visual interruption to the floor plane. Automation and control systems are concealed within bespoke metal housings finished to complement the surrounding interior, ensuring consistency with the historic setting while providing modern accessibility and operational reliability.
Together, the two glazed lobbies create a layered entry strategy that reduces air movement, improves thermal comfort and manages visitor flow without altering the underlying spatial hierarchy of the building.
A Reversible, Minimal Intervention
The frameless glass interventions at the Pitt Building demonstrate how contemporary glazing systems can be used to enhance the performance of historic institutional interiors while remaining visually subtle and fully reversible. By using structurally independent glass enclosures, the project avoids permanent alteration of the listed fabric and preserves flexibility for future adaptation.
The result is an improved arrival experience that meets modern expectations for comfort and accessibility, while maintaining the dignity, openness and architectural character of one of Cambridge’s most significant historic buildings.
Project Details
Building Type: Historic academic and civic building, now used for conferences and events
Primary Intervention: Two internal frameless glass draft lobbies
Main Lobby: Double‑height, three‑sided frameless glass enclosure
Approximate Dimensions (Main Lobby): 4.1m high × 3.0m wide × 1.3m deep
Glass Specification: Laminated toughened structural glass panels
Door Type: Double‑height pivot door within frameless glass screen
Secondary Lobby: Three‑sided frameless glass enclosure with automated sliding glass door
Automation: Concealed drive mechanisms and intuitive access controls
Fixings: Glass‑to‑glass junctions with minimal visible hardware
Design Approach: Structurally independent and reversible heritage intervention
