Asbestos cement barn roofs and solar: the 2026 UK guide

Asbestos cement was the dominant agricultural roof cladding from the 1950s through to the late 1980s — robust, cheap, fire-resistant, and (it turned out) a long-term liability that today blocks rooftop solar PV on a significant share of the UK’s farm-building stock. The good news in 2026: the combined re-roof and PV business case is well-established, trained asbestos contractors operate routinely in every UK region, and the maths usually works.

The regulatory position

What the rules say is narrower than a lot of installer copy suggests. HSE treats most work on asbestos cement as non-licensed, so long as the people doing it have the right information, instruction and training. Installers still avoid fixing through the sheets, and HSE’s task sheet A14 starts from a simple question: can the roof be overlaid with non-asbestos material rather than stripped? If it can, the new layer goes onto the existing purlins and drilling through the cement is kept to a minimum. For solar that leaves two routes, stripping and re-roofing first, or overcladding and fixing the array to the new skin, and the trade guidance on both is summarised in overclad or strip an asbestos cement farm roof. Sheets that break up and produce significant dust turn the job into notifiable non-licensed work, so method and training matter more than the licence question. The full legal position is on solar panels on asbestos cement farm roofs.

What it costs

The farm gets a modern, watertight, structurally improved roof AND a renewable energy asset for a single capital outlay.

When NOT to combine

There are situations where re-roof and PV should be sequenced rather than combined: (1) the building’s structural frame is also compromised — frame replacement is a different scope of work entirely; (2) the building’s use is changing and the future use doesn’t suit PV (residential conversion, demolition); (3) the building is small enough that the re-roof economics don’t stack alongside PV; (4) the operator has very limited capital and is making the re-roof a priority but cannot fund PV alongside.

Picking an trained asbestos contractors

Because most asbestos cement work is non-licensed, a licence number is not the test. Look for evidence of Category B (non-licensable work) training for the operatives, a method statement, a registered waste carrier and hazardous waste consignment notes; HSE says a licensed contractor is only needed where other asbestos materials such as lagging or insulating board are present. Also check recent agricultural work, appropriate insurance, and willingness to share scaffolding and access with the PV installer. A single principal contractor coordinating the asbestos team, the cladding installer and the PV team under one programme tends to work best.

Planning and grants

Permitted development under Class J, Part 14 GPDO 2015 typically covers the re-cladding (replacement of like for like, no change of use) AND the rooftop PV. No planning permission is normally required unless the building is listed or in a designated landscape area. The 100% Annual Investment Allowance applies to the PV portion of the capex (plant and machinery) but typically not the re-roof (building fabric) — talk to your accountant about how to apportion the bill of materials and labour for tax purposes. SFI has no asbestos-related or solar action.

Combining the re-roof and the PV

Where an asbestos cement roof is due for replacement anyway, the PV can be specified into the same project: one re-clad roof designed for the array load, one scaffold and one mobilisation, rather than a re-roof now and a PV retrofit later. Whether the combined case is stronger than re-roof alone depends on the roof area, the site’s electricity use and the quotes you receive, so ask each installer to price the re-roof and the PV separately and together.

If you’re planning a roof replacement on an asbestos-clad farm building, factor PV into the decision from day one — the combined business case is almost always stronger than re-roof alone.