Inventa

Transforming an empty retail unit into state-of-the-art laboratories and workspaces in central Oxford.

Through the adaptive reuse of two former retail warehouses, Inventa Innovation Hub now offers 6039 m² GIA of purpose-built laboratory and office space in central Oxford, just minutes from the railway station. The project transforms a redundant retail building on a flood-prone site into premium office and laboratory space for Oxford's growing life sciences sector.

We designed a new first-floor mezzanine within the existing building shell, almost doubling the lettable area to 5,297 m² of tenancy and meeting-room space across the ground and first floors. Front and rear extensions further maximise usable space while responding to the site’s flood-risk constraints.

Working closely with Owers Warwick Architects, Buro Four, Hilson Moran, Abakus, Equation and Stantec, we were the civil and structural engineering consultants for the feasibility and early-stage scheme design.

Life Sciences

Architect: Owers Warwick Architects
Client: Mission Street
Location: Oxford, UK

Impact

Our structural strategy introduced a new first-floor mezzanine within the retained building shell, almost doubling the lettable space and creating 5,297 m² of tenancy and meeting-room space across the ground and first floors.

A 300 mm-deep reinforced-concrete flat slab keeps the structural zone shallow, achieving approximately 2.7 m floor-to-ceiling height at ground-floor level while providing the stiffness and vibration control required for laboratory use.

A new column grid and corbel system enabled us to retain over 90% of the existing roof, with alterations focused on new rooflights and core structures, while creating flexible laboratory and office space below.

Our foundation and flood-risk strategies enabled the existing buildings to be adapted despite poor ground conditions, a high water table and the constraints of the retained structure.

Awards

2026 OxProp Awards - Best Commercial Building of the Year - Shortlisted
2025 AJ Retrofit and Reuse Awards -Adaptive Reuse category - Winner
2025 British Council for Offices Regional Award - Refurbished/Recycled Work place - Shortlisted
2025 OxProp Awards - Best Deal of the Year - Winner

History & Context

A former Argos warehouse, the Inventa site is located west of Oxford town centre near Botley Road. Until the mid-1800s, it was the main route connecting the towns of Oxford and Botley and was largely used as grazing land for domestic agriculture.

Around 1930, housing and industry moved into the area, and a large printing works was constructed on the site. This was demolished in 1994, and the previous retail park was built.

The site lies between the Botley and Seacourt Streams on a fluvial floodplain, making it vulnerable to flooding during high river levels. Our structural and geotechnical designs specifically addressed these challenging ground conditions and flood risks.

Our Approach

Flooding challenges

The site’s location on a flood plain posed multiple geotechnical challenges including made ground and potential contamination, a high water table at 2.5m below ground level, complex layered soil conditions and flood risk constraints requiring compensation measures. Its location on Botley Road, an area of archaeological significance, required careful excavation.

Our Development Infrastructure team had early-stage involvement working with the local authorities and the Environment Agency to develop the massing and flood risk management approach which was pivotal in making this project viable.

The superstructure

The superstructure design presented several key challenges. The integration of a new first-floor mezzanine within the two existing retail buildings required careful consideration of load transfer and structural connections, while accommodating the building plant and the performance requirements of the new laboratory spaces.

The removal of front and rear perimeter columns required complex temporary works to maintain the building's stability, while the retained roof structure needed new support through corbel connections to the reinforced-concrete columns.

Together, these interventions helped almost double the lettable space, creating 5,297 m² of tenancy and meeting-room space across the ground and first floors.

Wind loads and lab requirements

Additional challenges included accommodating plant equipment on the new extensions, integrating a two-storey stair core through the existing roof, and redistributing wind loads through new steel members.

The design also had to respond to the site’s flood-risk constraints while meeting the spatial and performance requirements of laboratory use. A 300 mm-deep reinforced-concrete flat slab keeps the structural zone shallow, achieving approximately 2.7 m floor-to-ceiling height at ground-floor level while providing the required stiffness and vibration control.

Engineering Solutions

We developed the new floorplate within the existing building shell while working carefully around the shallow foundations supporting the retained portal frame. New drainage infrastructure for the laboratory spaces had to be threaded through the existing ground floor, requiring sections of slab to be broken out and reinstated to accommodate new runs and drop points while preserving flexibility for future multi-tenant use.

To support the new first-floor structure, internal piles were introduced to create a reduced structural grid with longer spans. These had to be carefully coordinated around the existing strip foundations, which were found to be of poor quality and required local improvement to meet the proposed design life.

The new mezzanine uses a 300 mm reinforced-concrete flat slab, keeping the structural zone shallow and achieving approximately 2.7 m floor-to-ceiling height at ground-floor level, while providing the stiffness and vibration control required for laboratory use.

The transformation also extended beyond the original building line. At the gable end, existing steel columns were removed and replaced to support a new façade formed in portalised concrete, with carefully detailed thermal breaks to prevent cold bridging.

Stability across the new and retained structure was achieved through a combination of concrete shear walls and vertical cross bracing, coordinated around new openings and façade requirements.

To construct the piles, we broke out the existing slab at each pile cap location, cast the piles and pile caps, and then backfilled it with a Type 1 hardcore on top of the existing slab that was reinstated with rebar matching the existing one.

To address the removal of perimeter columns at the front and rear elevations, new 300 by 300mm reinforced concrete columns are positioned on an engineered 9m by 7.2m grid.

Cast corbels on these columns provide elegant support for the retained roof structure, creating a unified structural system between the new and existing elements.

This design allows for a cohesive colonnade entrance while maintaining structural integrity.

We designed strategic extensions at the front and rear of the building to house the new plant equipment requirements.

The flat roof areas on Level 02 now provide dedicated plant space, freeing up the entire main building footprint for laboratory and office use.

The new two-storey stair core is seamlessly integrated through the existing roof structure, with wind loads efficiently redistributed through new steel members to maintain structural stability.

More than 90% of the existing roof was retained, with alterations concentrated around new rooflights and core structures.

At roof level, the retained steel members were carefully propped and transferred onto the new structure where existing columns were cut away. Each connection between old and new required a bespoke design response.

New plant zones and building services were also integrated onto the lightweight roof and existing purlins through localised transfer structures, allowing loads to be distributed back to the retained portal frames while limiting the extent of strengthening works.