With an ageing building stock across the UK, flat roof refurbishment is fast becoming a key focus for specifiers, contractors and building owners. While leaks or visible damage may prompt an inspection, what lies beneath the surface often determines the success and cost-effectiveness of a refurbishment project. That’s why a structured process, beginning with accurate diagnosis and ending with a clearly defined specification, is essential.
Flat roofs can be deceptively complex. A visual inspection may reveal cracking, ponding water or general degradation, but these signs don’t always tell the full story. Water can travel significant distances beneath a waterproofing system before appearing inside the building, and a leak visible in one area may actually originate elsewhere. That’s where diagnostic tools are required. Moisture mapping, for example, enables surveyors to identify trapped moisture within the roof build-up. Using electromagnetic signals to detect changes in conductivity, the equipment scans below the surface, producing a visual map that pinpoints retained water. This helps reveal the extent of any issues that might otherwise go unnoticed.
A STRUCTURED PROCESS
A thorough refurbishment assessment begins long before anyone steps onto the roof. Internal inspections can reveal a lot about the deck type, which in turn affects both the survey method and the eventual specification. For instance, moisture mapping is highly effective on concrete decks, but less so on metal, where alternative methods may be needed.
Once on site a detailed inspection is conducted, using moisture mapping to confirm whether issues are localised or widespread. High-risk areas such as penetrations, joints and perimeters are identified and core samples taken where appropriate.
From there, refurbishment can follow one of three paths: retaining and maintaining sound roofs with only minor interventions, introducing new systems over stable existing structures, or undertaking a full strip and replacement where water ingress is extensive. The chosen route should reflect both the technical findings and the building’s intended lifespan. For instance, a facility nearing redevelopment may warrant a cost-effective short-term solution, whereas a building expected to remain operational for decades could benefit more from a comprehensive replacement.
SUPPORTING THE FULL REFURBISHMENT JOURNEY
Every refurbishment carries both financial and environmental consequences. Opting for a full replacement may seem like the most reliable choice, but it can result in unnecessary waste and expense if large areas of the existing system remain functional. Moisture mapping provides the evidence needed to plan targeted interventions, extending the service life while reducing disruption.
However, accurate diagnosis is only part of the process. Once a solution is identified, other technical considerations come into play. Wind uplift, drainage falls, and thermal performance are all key factors when ensuring a roof refurbishment or replacement is fit for purpose. A well-supported programme combines this design expertise with trained, approved contractors who can deliver the specification as intended.
Manufacturer support during installation can also make a big difference. Site operatives who monitor quality and progress ensure that what’s designed in practice is what is installed and that it remains compliant with Building Regulations, as required by the Building Safety Act.
MAINTENANCE AND LONG-TERM VALUE
Even the best refurbishment will only perform as expected if it’s properly maintained. A minimum of twice-yearly inspections, typically before and after winter, are required under BMI guarantees to remove debris, check outlets and identify any damage caused by other work near the roof area. Changes in building use can also affect performance; for instance, kitchen extracts or new service penetrations can compromise the roof’s performance.
Regular maintenance not only extends the roof’s lifespan but also safeguards the client’s investment. In the long run, it’s often the difference between achieving a 25-year performance or facing avoidable repair within a decade. www.bmigroup.com/uk