Why the asbestos roof is the first question on most farm-building projects
Corrugated asbestos cement was the standard roof on British agricultural buildings for decades, and the supply of chrysotile products was not prohibited in the UK until November 1999. Any pre-2000 shed with a grey corrugated roof should be presumed to contain asbestos until a survey says otherwise. That matters for solar for a simple physical reason: the sheets are brittle, the fixings would disturb the material, and no competent installer will drill rails into them. The panels need a roof they can be fixed to, so on these buildings the roof decision comes before the array and usually costs more than it.
What the decision is not is a legal obligation to remove the asbestos. That claim appears in a lot of installer copy, sometimes with “HSE-licensed contractor” attached. Both parts are wrong, and getting them right changes the budget.
What the regulations actually require
| Point | Verified position (September 2026) | Source |
|---|---|---|
| The duty | Owners and occupiers of non-domestic premises with maintenance responsibility must manage asbestos: find it, assess its condition, keep a record and a plan, and manage the risk. Farm buildings are non-domestic premises. | Control of Asbestos Regulations 2012, regulation 4; HSE asbestos FAQ |
| Removal | Not required by the regulations for material in good condition. Removal is a practical choice when the roof is at end of life or must carry fixings. | CAR 2012; HSE guidance on the duty to manage |
| Licensing | Most work on asbestos cement can be carried out without a licence, provided workers have appropriate information, instruction and training. Asbestos cement is a lower-risk material than sprayed coatings, insulation and lagging, which are licensable. | HSE asbestos FAQ |
| Method | Intact sheets should not be broken into smaller pieces; they are removed whole, double-wrapped in 1000-gauge polythene and labelled. Aggressive disturbance — breaking or smashing — is high-risk and can be a reportable incident. | HSE asbestos FAQ |
| Disposal | Asbestos waste goes only to a licensed disposal site, with the consignment paperwork kept with the building’s asbestos record. | HSE asbestos FAQ |
| Tax treatment | Panels are special-rate plant and qualify for the 100% Annual Investment Allowance; the roof is building fabric and does not. Separate invoices. | CAA 2001; HMRC capital allowances guidance |
Strip and re-clad
The sheets come off whole, wrapped and consigned to a licensed site; the purlins are inspected and replaced where corroded; a new profiled-steel roof goes on, often with rooflights re-planned around the array; then the panels are fixed to the new sheeting with purpose-made brackets. The result is a new roof with a long life and a clean substrate, and the PV is designed with the roof rather than around it. It is the right route when the sheets are cracked, delaminating or leaking, when the building is due a roof anyway, or when the frame cannot take the weight of an over-clad.
The cost is the removal, the disposal and the new roof, before a panel is bought. This site’s indicative figures for the strip, the re-clad and the sequencing are on combined re-roof + PV; the point to hold onto is that the PV business case can carry part of a roof the building needed anyway, but it cannot make a roof free.
Over-clad
A subframe is fixed through the existing sheets to the purlins, a new profiled-steel skin goes over the top, and the panels are mounted to the new skin. The asbestos stays in place, undisturbed and recorded in the asbestos register as a managed material. Over-cladding avoids the removal and disposal cost and is quicker, but it adds dead load, so the purlins and frame must be checked for the combined weight of the subframe, the new sheet and the panels plus wind uplift; on lighter early portal frames that check fails. It also leaves a future owner with an asbestos roof under a steel one, which a buyer’s surveyor will price.
Leave it and put the array elsewhere
Where the asbestos roof is sound and the building is not the best host anyway — a poor orientation, a shaded site, a low load — the honest answer is often to leave that roof managed in place and put the array on a newer building or, with planning permission, on the ground. The duty to manage is satisfied by the survey, the record and a plan; there is no clock running on removal.
How to decide, and what to ask for
- Get the asbestos survey first. If the building does not already have one in its register, that is the duty to manage talking, regardless of solar.
- Get a structural opinion on the frame. The over-clad question is decided by purlin and rafter capacity, not by preference.
- Price both routes with the PV. Ask installers to quote the array on a re-clad roof and on an over-clad roof, with the roofing on a separate invoice from the PV plant.
- Check who does the asbestos work. Trained operatives with the method statement, wrapping and consignment paperwork — the HSE position is that a licence is not usually needed for asbestos cement, but training and method are.
- Keep the paperwork with the building. Survey, method statement, consignment notes and the updated register: a future buyer, lender or landlord will ask for all of them.
The rest of the rules for the building — permitted development on the roof, the G99 connection, the tax split — are on solar panels for agricultural buildings and planning permission for solar panels on farm buildings. For the installers who handle re-roof and PV together, and how to check them, see agricultural solar panel installers; for the head-term overview, solar panels for farm buildings.
Asbestos roof questions
Can you put solar panels on an asbestos roof?
Not directly. Installers will not normally drill or fix through asbestos cement sheets, because the fixings disturb the material and the sheets are brittle and cannot safely carry the point loads. The array goes on after the roof has been stripped and re-clad, or after the sheets have been over-clad with a new profiled-steel skin on a subframe. Which of those is right is a structural and financial decision, not a legal one.
Does the law require an asbestos roof to be removed before solar?
No. The Control of Asbestos Regulations 2012 impose a duty to manage asbestos in non-domestic premises (regulation 4): to find it, assess it, record it and manage the risk. They do not require removal of material in good condition. Removal becomes the practical route when the roof is at the end of its life or when the panels need a substrate they can be fixed to.
Do I need a licensed asbestos contractor for a cement roof?
Usually not. The Health and Safety Executive states that most work on asbestos cement can be carried out without a licence, provided the people doing it have the right information, instruction and training, and asbestos cement is treated as a lower-risk material than sprayed coatings, insulation or lagging. The work still has rules: sheets are removed intact rather than broken, double-wrapped in heavy polythene and labelled, and taken to a licensed disposal site. Breaking or smashing sheets is high-risk and can be a reportable incident.
Is over-cladding an asbestos roof allowed?
Yes, and it is a common route on farm buildings: a new profiled-steel skin is fixed to a subframe over the existing sheets, leaving the asbestos undisturbed and managed in place. It avoids the removal and disposal cost but adds weight, so the purlins and frame must be checked for the combined load of the over-clad and the panels, and the asbestos remains a managed material for the life of the building.
How old does a farm building have to be to have asbestos cement?
Asbestos cement products were in wide use in UK agricultural buildings for decades and the supply of chrysotile (white asbestos) products was prohibited in the UK from November 1999. Any corrugated cement roof from before 2000 should be presumed to contain asbestos until a survey says otherwise, which is exactly what the duty to manage asks for.
Does the re-roof qualify for the same tax relief as the panels?
No. The panels are special-rate plant and qualify for the Annual Investment Allowance; the roof is building fabric and does not. Ask for the roofing and the PV plant on separate invoices so your accountant can apportion the spend correctly.