Do you need a bat survey before repairing a roof?
- Mar 5
- 4 min read
Repairing a roof on a historic building is normally seen as straightforward maintenance.
Tiles slip, ridge mortar deteriorates and flashings eventually fail. However, when a building is old enough to contain gaps, voids and quiet roof spaces, it may also have become a roost for bats.
This is where things become more complicated.
In the United Kingdom bats are protected by some of the strongest wildlife legislation in existence. The law does not simply protect the animals themselves — it also protects the places where they roost. Because of that, repairing a roof without first considering the possibility of bats can create legal risks for building owners.
Understanding when a bat survey may be needed helps avoid delays, legal problems and unexpected costs.
Why bats use historic roofs
Historic roofs offer exactly the sort of environment bats prefer.
Openings beneath ridge tiles, gaps between slates, spaces behind fascia boards and cavities within timber structures can all provide sheltered access points. Once inside, bats may roost beneath roofing felt, between rafters or in small crevices within the roof structure.
These spaces are usually dry, dark and undisturbed. That makes them ideal for seasonal roosts.
Because older buildings tend to contain more small gaps and cavities than modern construction, they are far more likely to host bats.
The legal protection of bats
In England all bat species are protected by two main pieces of legislation:
Wildlife and Countryside Act 1981
Conservation of Habitats and Species Regulations 2017
Together these laws make it illegal to:
deliberately harm or capture a bat
damage or destroy a bat roost
obstruct access to a roost
disturb bats while they are using a roost
The important point is that the roost itself is protected, even if bats are not present at the time.
This makes bat protection unusually strict. Many other areas of planning or building law allow discretion or retrospective solutions. Bat legislation generally does not.
If a roost is damaged without proper licensing, the offence has already occurred.
When a bat survey is required
A bat survey is not required for every roof repair. However, surveys are commonly recommended when:
the building is historic
roof voids or cavities are present
the property is rural or surrounded by trees
bat droppings or staining are visible
planning permission or Listed Building Consent is being sought
Planning authorities frequently request bat surveys as part of the planning process where the risk cannot be ruled out.
In practice many conservation architects recommend considering a bat survey whenever significant roof repairs are planned on older buildings.
What a bat survey involves
Bat surveys are carried out by licensed ecologists.
The first stage is usually a preliminary roost assessment, which involves inspecting the building for signs of bats such as droppings, staining or entry points.
If evidence suggests bats may be present, further surveys may be required. These are typically carried out at dusk or dawn during the warmer months when bats are active.
The aim of the survey is to establish:
whether bats are present
which species are involved
how the building is being used
what mitigation may be required
Timing considerations
Bat surveys can affect the timing of building work.
Activity surveys usually need to take place between May and September, when bats are active.
If roof repairs are planned outside this period and surveys have not been carried out earlier in the year, it may be necessary to wait until the following survey season.
This is one reason why early planning is important. A roof that urgently needs repair may still need to wait if bat surveys are required.
Typical costs
The cost of bat surveys varies depending on the size of the building and the complexity of the investigation.
Typical Midlands costs in 2026 might include:
preliminary bat inspection: £300–£600
activity surveys: £600–£1,500 or more
If bats are confirmed, mitigation measures may also be required. These could include bat boxes, access tiles or ecological supervision during construction.
Although these costs can be frustrating, they are usually modest compared with the cost of a full roof repair.
Get it wrong — what are the consequences?
Because bat protection law is strict, damaging a bat roost without proper assessment can lead to serious consequences.
Possible penalties include:
unlimited fines
confiscation of equipment used in the offence
in serious cases, imprisonment
These penalties are rarely applied to ordinary building repairs carried out in good faith, but the law does allow them.
More commonly, the consequences involve investigation, project delays and enforcement action.
Work may be halted while the situation is investigated, and mitigation measures may be required after the event.
How would anyone know?
People often ask how such issues come to light.
In practice wildlife offences are usually reported by:
neighbours
ecologists
conservation officers
members of the public
Bats themselves are also very visible to those familiar with them. Droppings, staining or bat activity at dusk are easy for specialists to recognise.
If bats are suspected during building work, the local authority or police wildlife officer may become involved.
Who investigates and prosecutes?
Wildlife offences are normally investigated by:
Police wildlife crime officers
Natural England
local authorities in some circumstances
Prosecutions are usually brought through the courts under wildlife legislation.
Natural England may also be involved where licences are required.
How likely is prosecution?
In reality prosecutions for bat offences are relatively uncommon.Across England there are typically only a handful of successful prosecutions each year, usually involving deliberate destruction of roosts or significant development projects where warnings were ignored.
However, the rarity of prosecutions should not be misunderstood as a lack of enforcement. Investigations are taken seriously, and projects can be delayed or altered significantly where bat protection is breached.
For building owners the main risk is disruption to the project and unexpected costs, rather than criminal prosecution.
The Longnor Heritage approach
At Longnor Heritage we encourage building owners to consider wildlife early when planning roof repairs.
Where there is any reasonable chance that bats may be present, arranging a preliminary inspection can provide clarity before work begins.
With sensible planning most roof repairs can proceed successfully while respecting the legal protection given to bats.
Historic buildings and wildlife often coexist comfortably, and careful preparation helps ensure that both are protected.
