Re-roofing barns and agricultural buildings

Barns and farm buildings vary more than houses. A modern portal-frame shed usually carries profiled sheets: steel, or fibre cement. An older timber-framed barn on a farm near Chichester or in the Arun valley may have clay tile, slate or pantile on laths and rafters. Some buildings have been patched over decades with whatever was to hand, so a single roof can hold three or four coverings.

That mix matters, because each covering fails in its own way. Steel sheets rust at cut edges and fixings. Fibre-cement sheets crack and go brittle. Old tile roofs lose tiles when the nails or battens give way, and the frame beneath may have been wet for years.

The survey begins with a close look at all of it: sheets, fixings, gutters, rooflights, the purlins or rafters, and the eaves where timbers rot first. Every fault gets photographed, and those photographs travel with the quote. A section that still has years left in it stays as it is.

HSE tells owners to treat any building dating from before 2000 as a likely source of asbestos. Plenty of older barn roofs are asbestos cement sheets, and HSE stresses that such sheets cannot be trusted to carry a person, so nobody should step onto one without proper roof access equipment.

HSE puts careful, whole-sheet removal of weathered cement sheeting in the lower tier of control, which needs no licence. If the sheeting cracks up or is badly knocked about, the job rises a tier: it must be notified to the regulator ahead of the start. Each sheet comes down to the ground by hand, since throwing or chuting it is ruled out, and the waste is double-wrapped and kept in a lockable skip.

Household and farm asbestos waste travels under a consignment note, which the contractor signs for the waste he produces. That paperwork is a good reason why a barn re-roof should not be priced until the sheets have been identified. Our guide to asbestos cement industrial roofs goes through the rules in more detail.

Barns are popular with wildlife. GOV.UK says all bat species, their breeding sites and resting places are fully protected by law, and that activities affecting bats include repairing or replacing a roof. Droppings in a loft space, or bats seen emerging at dusk, mean the work should pause until you have taken advice.

Nesting birds have protection as well. A nest in use, or half built, is protected: GOV.UK calls intentional damage to one an offence. Swallows are the usual case on a farm, tucked on a beam or rafter inside an open-sided building.

In practice that means the survey looks for signs of both, and the programme allows for waiting if a nest is active. Tell us what you already know, such as where birds come and go and which roosts you have noticed. It is far easier to plan around them from the start than to halt a scaffold half-way through.

A barn that is listed brings a different route. Under the Planning (Listed Buildings and Conservation Areas) Act 1990, an alteration that changes a listed building's character needs listed building consent. The South Downs National Park Authority treats upkeep and small repairs done in like materials as not needing consent, but swapping the whole covering for a different material may not be, so speak to the council before you order anything.

Even an unlisted barn inside a conservation area or the National Park deserves a call to the planning team. A matching re-cover is treated differently from a change in how the building looks. Section 55 of the Town and Country Planning Act 1990 puts to one side any work with no material effect on how the building looks from outside.

Traditional materials also change the job. Clay and natural slate roofs can often be repaired and partly reused, and the frame beneath may need a carpenter before a roofer. A mixed repair is common, and it asks for less than stripping everything when the survey shows it will hold.

The right covering depends on the building's use, the frame and the pitch. Profiled steel and composite sheets are light and fast to lay on a big plain roof. Fibre-cement alternatives, tiles and slates suit smaller or older buildings where appearance matters. See our guide to replacing steel roof sheets for what that job involves.

Weight is the check people skip. A heavier covering on an old frame can overload purlins that have been sagging for years. The Planning Portal says to have an engineer or surveyor check before a markedly heavier or lighter covering goes on, and lists a rise of 15 per cent or more as a reason for building control.

Condensation can be a hidden problem in livestock and storage buildings, so the survey notes the ventilation and the insulation. Your written quote gives a single total, and the verdict and photographs come before it. Our commercial roofing page lists other work we undertake on non-domestic buildings.