Most UK warehouse buildings constructed pre-2000 have asbestos cement roofs (typically AIB or chrysotile-cement profiled sheeting). Asbestos was widely used in commercial roofing through the 1970s-1990s before restrictions tightened. These roofs cannot accept rooftop solar PV — health-and-safety regulations prohibit working on asbestos roofs without enclosure, and asbestos cement is structurally unsuited to additional dead load.
Why solar can't be retrofitted to asbestos roofs
Three reasons: (1) Health-and-safety: HSE regulations require licensed asbestos removal contractor for any work disturbing asbestos cement. Solar mounting (whether ballasted or mechanical) disturbs the roof surface. (2) Structural: asbestos cement profiled sheeting is brittle and cannot accept additional dead load (PV + ballast 15-20 kg/sqm). (3) Roof condition: pre-2000 asbestos roofs are typically nearing end-of-life with surface degradation, sealant failure, and potential structural issues — PV adds risk to an already-marginal roof.
Combined re-roof + PV economics
The right approach: replace the asbestos roof with modern profiled steel (Kingspan, Tata Colorcoat) plus installation of PV on the new roof in a single project mobilisation. Combined cost: re-roof £30-60/sqm + PV £700-900/kW. For a 200,000 sqft warehouse: re-roof £750k + 1 MW PV £750k = £1.5m total. Very different economics from £750k PV alone — but the PV business case often justifies the re-roof over project lifetime. Without solar, re-roof is sometimes deferred indefinitely; with solar, re-roof becomes self-funding.
Asbestos removal process
Licensed asbestos removal contractor only (HSE-licensed). Full enclosure of removal area. PPE-protected workforce. Negative-pressure airlock systems. Air monitoring throughout. Asbestos waste classified as hazardous (Asbestos Waste Code 17 06 01) — disposed at HSE-licensed facility. Typical removal cost £20-40/sqm of roof area. Re-roof installation follows after asbestos clearance certificate. We coordinate the asbestos removal with our re-roof contractor.
Common questions about asbestos roof
Why can't asbestos roofs be retrofitted?
Three reasons: HSE regulations prohibit working on asbestos roofs without licensed contractor; asbestos cement is structurally unsuited to PV ballast load; pre-2000 asbestos roofs are typically nearing end-of-life. The right path is combined re-roof + PV.
How much does asbestos removal cost?
Typical £20-40/sqm of roof area for asbestos cement profiled sheeting removal. Disposal as hazardous waste at HSE-licensed facility. Combined with re-roof £30-60/sqm and PV install, total project cost roughly £75-100/sqm of roof for asbestos removal + new roof + PV.
How does the PV business case justify the re-roof?
Without solar, re-roof is often deferred indefinitely (no immediate ROI). With solar, the £700-900/kW PV install plus annual energy savings make the combined project economically viable. Combined payback 6-9 years vs re-roof alone (no payback). PV often essentially "pays for" the re-roof over project lifetime.