Retail roofing / Cardiff city centre
RAAC roof replacement, phase 1
Full structural replacement of a failing RAAC roof above a trading shopping centre, delivered with zero disruption to the retailers below.
JPS was appointed to remove and replace a defective Reinforced Autoclaved Aerated Concrete (RAAC) roof at St David's Shopping Centre in Cardiff city centre. The existing structure was over forty years old and presented a significant structural risk, so a full replacement was required to safeguard the long-term integrity of the asset. Every hour of the works took place above a fully operational shopping centre.
The challenge
Replacing a structural roof deck in a live retail environment introduced constraints that shaped the entire programme.
- Maintaining continuous trading for ground floor tenants
- Working within constrained service deck and access conditions
- Ensuring public safety at all times
- Coordinating tenants, centre management and specialist contractors
- Keeping fire and life safety systems fully operational throughout
Our approach
A phased, heavily coordinated delivery strategy kept risk contained and the centre trading.
- Temporary roof structures over Block 1 (~1,000m²) and Block 9 (~250m²) for full weather protection
- Safe isolation, removal and relocation of A/C condensers and air handling units
- Decanting and secure relocation of tenant stock to off-site storage
- Temporary welfare and site infrastructure to support operations
- Temporary compartmentalisation of fire safety systems to maintain compliance at every stage
- Continuous communication with centre management and tenants
The solution
With the RAAC safely removed, a new TATA RibDeck steel deck gave immediate structural stability and a consistent substrate, installed far faster than a traditional concrete solution. On top of it went a three-layer built-up felt system: an Alumasc Derbigum Olivine cap sheet over high-performance bituminous waterproofing layers, with 210mm of Rockwool insulation to hit the required thermal performance. The build-up delivers proven long-term waterproofing, high resistance to weathering and UV, and a meaningful reduction in energy demand.
Results
- Zero disruption to trading for ground floor tenants
- High-risk structural works safely delivered in a live environment
- Full fire and life safety compliance maintained throughout
- Enhanced long-term performance of the asset
- Positive engagement with tenants, client and centre management
8 photographs from site.
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Tendering something awkward?
Occupied buildings, fixed trading dates, listed structures and phased handovers are the normal condition here. Tell us the constraint and we will tell you how we would work around it.