Multiple Bonded Warehouse Roofing Design and Replacement
12 Months
1200 m2
COMMERCIAL ROOFING PROJECT - SCOPE OF WORKS
The tender was designed to enable the client to determine the type, capacity, related costs, and technical capabilities of the organisations invited to participate. The client would select the preferred contractor based on an evaluation matrix that considers their submissions. The warehouse roofs had reached the end of their service life, requiring a comprehensive replacement project. This involved a series of upgrades, including replacing the roof sheets of Warehouse 1 and 2 to prevent water ingress, condensation, and corrosion, as well as improving the ridge to maintain existing ventilation levels with at least 1% free air openings.
Starfish Construction examined the gutters and linings for potential upgrades, replacements, or redesigns. Likewise, internal and external flashings were to be upgraded or replaced, and planned improvements to the current roof access systems aimed to make maintenance from the ground to all gutters easier. The roof’s fall protection system was also to be upgraded to enhance safety during future maintenance. The project scope covered inspecting any defective roof support structures and proposing rectifications. A maintenance schedule and work instruction risk assessments were included, and the upgrades also extended to the rainwater downpipes.
Turnkey Construction
ENSURES VALUE AND SYNERGY
Our sister company, Starfish Environmental and Asbestos Services (SEAS), a part of the Starfish Construction Group and a licensed asbestos contractor, assisted in removing the asbestos insulating board (AIB) beneath the roof liner panels as part of the roof upgrade scope. To deliver a well-structured and competitive tender, Starfish Construction utilised the expertise of its integrated divisions. This approach ensured that every aspect of the project was carefully considered and designed to add value for the client. Our team conducted detailed structural calculations of the existing roof steelwork and developed designs for new purlins and their corresponding spacings. This enabled us to propose a robust composite roof system that can support maintenance access while reducing the risk of condensation.
We further conducted a comprehensive condensation risk analysis of the proposed roof sheet, confirming that the system would prevent condensation and protect both the new galvanised roof purlins and the valuable casks stored within the warehouse. Additionally, we designed an appropriate ridge ventilation system, supported by calculations ensuring at least 1% airflow relative to the warehouse volume. Rainfall index calculations were also performed to confirm the guttering system could withstand modern rain intensities, including extreme 1-in-50-year events. To future-proof the building, we incorporated the design and layout of a fall protection system, ensuring safe and efficient maintenance throughout the roof's lifespan and providing long-term reassurance to the client.
SAFE TO WORK REPORT
Given the complexity of working within bonded warehouses, safety was of paramount importance. Starfish Construction undertook a comprehensive Safe System of Work Report to ensure that every stage of the project could be delivered without compromise. A range of scenarios was modelled to identify the most effective safety systems, tailored to the unique conditions of each warehouse.
To protect the workforce at height, perimeter top-lift scaffolding was designed for the eaves, alongside bolted roof edge protection at the verges. Fully tensioned, walkable safety netting was installed above the palletised casks, creating a secure environment while protecting valuable stock. Where roof removal required direct access, we developed a solution that combined a fully boarded platform on rack-and-tier cask storage with lightweight working platforms built underneath the roof. This provided operatives with a safe, stable platform for removing sections of the roof without risk to themselves or disruption to the warehouse contents.
The presence of asbestos insulation board (AIB) necessitated additional measures. To manage this, a full scaffold was installed within the palletised cell to enable the erection of a licensed enclosure, allowing for safe and compliant asbestos removal.
The initial step in our comprehensive project planning involved appointing a structural engineer to conduct a thorough assessment. Their responsibilities encompassed evaluating the condition of the existing primary and secondary steelwork, which is crucial for ensuring the project’s structural integrity. Additionally, we entrusted the engineer with the critical task of performing snow and point-loading calculations. These calculations were essential in determining the precise spacing required for the purlins, which in turn determined the appropriate thickness of the roof sheeting. These critical components would guarantee the roof’s durability and resilience.
Furthermore, we based our decision-making process regarding the thickness of the roof sheets on data from a Scotch Whisky Research Institute report, which provided valuable insights into optimising U-values to minimise ethanol loss. This information was instrumental in guiding our approach to insulation. The report highlighted a delicate balance: insufficient insulation led to increased ethanol loss, while excessive insulation proved unnecessary, yielding negligible benefits. By incorporating these findings into our design, we ensured that our roof sheet specifications were both environmentally efficient and economically viable for our client’s needs.
Our success
OUTCOME AND DELIVERED VALUE
By acting as both Principal Designer and Contractor, Starfish Construction showcased the strength of its turnkey model. Our integrated approach, combining in-house design, structural engineering, scaffolding, HSQE oversight, and licensed environmental services, ensured the project flowed seamlessly from survey through to safe and compliant delivery.
The roofing replacement was completed over 12 months across 12,000 m² without a single safety incident, despite the challenges of working in a COMAH-regulated environment. Strong communication and collaboration were central to success, with the client actively engaged through weekly progress updates and awarding Starfish further licensed asbestos removal works as a result of their confidence in our performance.
This project demonstrates what our turnkey construction model delivers: complete technical capability, efficient delivery, uncompromising safety and quality, and a client-focused approach—all delivered by our in-house divisions working as one.
