An Integrated Approach to Car Park Life Extension
Extending the service life of an ageing multi-storey car park rarely involves a single intervention. Understanding the condition of the structure, identifying deterioration mechanisms and developing the right engineering response are all critical to achieving a durable and cost-effective outcome.
Interspan brings these capabilities together through an integrated service offering that combines structural investigation, durability design, post-tensioning, structural strengthening design, and operational delivery. This allows our teams to support owners and asset managers from initial condition assessment through to engineered repair, strengthening and long-term protection.
Investigate → Diagnose → Design → Strengthen → Protect → Extend Service Life
By combining investigation, engineering and specialist delivery within one team, Interspan can develop solutions based on the actual condition and requirements of each structure – helping asset owners make informed decisions, minimise disruption and extend the useful life of their car park assets.
Investigation & Diagnosis
Our repair and strengthening approach begins with a thorough investigation and diagnosis of the underlying causes of deterioration.
Destructive Investigation
Using small drill holes, we conduct air compressor testing and endoscopic review to assess internal conditions. GPR is used first to safely locate post-tensioning tendons and embedded reinforcement before any drilling occurs.
Non-Destructive Investigation
Following targeted destructive tests, Impact Echo and other non-destructive methods are used to map voids or defects within partially grouted tendons or concrete elements. This enables precise planning of the remediation process and selection of the most effective grouting and strengthening systems.
In-House Engineering & Design
Every project benefits from Interspan’s in-house engineering and design capability. Our engineers collaborate closely with consulting engineers and asset owners to evaluate all technical and economic factors — including material selection, serviceability, constructability, appearance, and long-term maintenance requirements. This integrated process ensures the proposed solution is not only structurally sound but practical and cost-efficient in operation and upkeep.
Strengthening Techniques
Depending on the structural requirements and condition, Interspan designs and installs a range of strengthening systems, including:
These techniques provide durable, visually discreet, and corrosion-resistant solutions — ideal for operational assets such as retail or multi-level carparks where minimising disruption and maintaining aesthetics are critical.
Adaptive Reuse and Sustainable Renewal
As more property owners look to repurpose or upgrade existing assets, carparks present opportunities for adaptive reuse, vertical expansion, or integration with new mixed-use developments. Interspan’s experience in structural reuse and strengthening helps clients unlock these opportunities while reducing waste and embodied carbon.
By combining engineering precision, forensic investigation, and sustainable materials, we deliver outcomes that extend asset life and enhance long-term value for developers, asset managers, and facility owners
Carpark Strengthening for Meadowhall, Sheffield
CFRP-based solution adopted over conventional structural steel framing.
At one of the UK’s busiest retail destinations, Interspan’s repair and strengthening team was engaged to restore capacity and extend the life of a major car park – all while keeping it open to the public.
The HERB project involved 3,000m² of carbon fibre slab strengthening, 2.5km of carbon fibre wrap, 0.5km of laminate, 1.2km of steel plates, more than 6,000 high-tensile anchors and 6,000 full-depth slab penetrations – delivered over more than 7,000 labour hours using 4.4 tonnes of epoxy resin.
Structural Strengthening for University Car Park
The Health Education Research Building (HERB) project for the University of Newcastle will redefine the educational landscape for nursing and midwifery for the Hunter Region and beyond. It will offer state-of-the-art facilities, including simulation labs, innovative teaching spaces, and communal areas designed for collaboration. It also integrates the Office of the Pro Vice Chancellor for the College of Health, Medicine, and Wellbeing, emphasising the unification of health disciplines under one roof to foster cross-disciplinary collaboration and innovation.
Tackling Challenges with Structural Strengthening
During the design development phase, a significant challenge emerged: the need for structural strengthening of an existing concrete slab to support the building’s ambitious plans.
This challenge was a critical hurdle requiring precision and innovation to maintain the project’s timeline.
The remediation approach involved designing and implementing a comprehensive system incorporating fire-proof carbon fibre laminate, wrap, and steel plate strengthening elements. This solution ensured not only the slab’s structural integrity but also the seamless progression of the construction schedule.
Edinburgh Airport Multi-Storey Car Park – Investigation
At Edinburgh Airport, Interspan recently completed a comprehensive structural investigation of the five-storey Terminal Multi-Storey Car Park. Constructed in 2004 using post-tensioned slabs and band beams, the highly utilised structure is approaching the midpoint of its design life, making a detailed understanding of its current condition important for future maintenance and asset management planning.
The investigation combined non-destructive testing with targeted intrusive investigation and specialist Post-Tensioning Special Investigation techniques. More than 1,350 individual investigation locations were digitally recorded, providing Edinburgh Airport and its consulting engineer with a detailed evidence base to assess deterioration and corrosion risk, and to inform future monitoring, repair, and long-term management of the structure.
Interspan Strengthening & Repair
Interspan uniquely integrates in-house post-tensioning expertise, advanced forensic diagnostics, and cutting-edge strengthening technologies to enable a single-source delivery model trusted by global developers for complex retrofit and reuse projects.
NEW STRUCTURES
The Interspan Group brings unique expertise in post-tensioning, construction methodology, and lifting operations that reduce CO₂ emissions, material use, and construction program duration.
EXISTING STRUCTURES
We specialise in helping clients extend the lifespan of concrete structures through advanced repair, strengthening, and carbon-fibre solutions. Adaptive reuse projects are a perfect fit for our expertise, helping to minimise waste while delivering safe, modern outcomes that support community growth.
Over the last decade, the Interspan Group has become a market leader in the application of CFRP-strengthening solutions, with notable projects including the award-winning The Space House in London and the Quay Quarter Tower in Sydney.
Quality Assurance
Quality Assurance is of immense significance to Interspan because it impacts the safety of our operatives and future occupants, the long-term durability of our structures, and our client satisfaction and relationships.
Interspan is accredited under CARES APTO1 for the Production and Supply of Post-tensioning Anchorage Systems and is the only post-tension contractor in Australia accredited under CARES APTO4 for the supply and installation of Post-tensioning systems in concrete structures.
Sustainability
Post-tensioning and adaptive reuse are powerful design approaches that reduce material use and embodied carbon—delivering more efficient, resilient, and sustainable structures for the future.
