The short answer
Roof work can often go ahead, but not always straight away. A bird's nest is protected while it is occupied or still being built, and bats are covered in full by law, roosts included, even during a roof repair or replacement. If you know or suspect either is present, tell your roofer before anything is lifted, because the plan may need to change.
Where the law stands on bats and birds nesting in a roof, when work has to pause, and how a bat survey can change the timing.
What the law protects
Two separate sets of rules apply to a roof. For birds, the Wildlife and Countryside Act 1981 makes it a criminal matter to wreck a nest with birds in it, or one that is half built, when that is done on purpose. The word on purpose carries weight in the law, but nobody should treat it as a loophole. A roofer who strips a ridge with a nest under it knows what is there, so the safe habit is to look first and stop if there is one.
Bats get stronger protection. The 2017 habitats regulations bar anyone from deliberately disturbing a protected animal, and separately from harming the spot where it breeds or rests. That second ban does not require a deliberate act. GOV.UK states that every bat species is covered in full, and says that mending or renewing a roof is one of the jobs that may disturb them.
Neither rule means a roof cannot be worked on. It means the work is planned around whatever lives there. This is a plain summary, not legal advice for your own case, so ask your council's planning team or a qualified ecologist if you are unsure.
Birds nesting in the eaves or ridge
Birds look for gaps under eaves, soffits and ridge tiles, and some settle in gutters or at the verge. Because the offence turns on whether a nest is occupied or being built, the question to ask is whether this one is active. An empty old nest is a different matter from one holding eggs or chicks.
If an active nest turns up at the survey or on the day, work around it stops. Where the job allows, the crew carries on elsewhere on the roof and leaves that section until the young have flown. That can mean a second visit, so it helps if you mention what you have seen or heard beforehand, such as chirping from a soffit or birds flying into the same gap.
GOV.UK states that no licences are available to permit development or construction where birds are concerned. In plain terms, you cannot apply for permission to remove a nest because a building job is booked. There are no nesting-season dates we can give you, so the judgement is made on what is actually found on your roof, not by a calendar. Once the nest is finished with, closing the gap with a bird-safe fitting stops the problem coming back.
When a bat survey is needed
Bats roost in gaps behind fascias, under ridge and hip tiles, between felt and tiles, and in quiet, warm lofts. You rarely see the animals themselves. The usual clues are droppings below a gap, staining around an entry point, or a sighting at dusk near the roof. Older brick-and-tile houses with gaps and untreated timber offer more room than a sealed modern roof, though no house type is ruled out.
If there are signs, the job is not simply carried on. A bat survey is done by a qualified ecologist, who looks for evidence, may return for dusk or dawn visits, and writes up what they find. Where roosts are present and the work would affect them, the ecologist advises on what permission is needed and how to proceed. A licence is not always required, and nobody should say otherwise before the survey is done.
Please do not block a gap or lift a ridge tile yourself because you suspect bats. Leave the area alone and tell your roofer. Damaging a roost in a hurry can break the law even when the intention was good.
What it does to your timetable
The honest effect is delay. A walk-round by an ecologist can sit alongside the normal survey stage, but a full bat survey with dusk visits takes calendar time and needs suitable conditions. The ecologist will tell you which dates are possible, and a licence, if one turns out to be required, adds an application period on top. A start date cannot be promised until that picture is clear.
If your roof is leaking, the position is different. A temporary make-safe, such as sheeting over a hole, can sometimes be done in a way that avoids the roost, and stopping the water getting in is the priority. Mention the suspected bats when you call so the make-safe is planned around them.
It helps to read our answer on the best time of year for roof work, which shows how season and booking fit together. If a survey, scaffold and a licence all add time, our scaffolding answer covers the access side. Our home page explains how we survey a roof before pricing it. Photos of the gap, the droppings or the nest are what we would ask you to send before a visit.
More on this in Roofers in Crawley: the full guide
Two more wildlife questions
Can I be fined for disturbing a nest during a roof repair?
Wrecking a nest with birds in it, on purpose, may break the 1981 wildlife legislation, and the courts set the penalties, not us. The practical rule is to check for activity before work begins, leave an active nest alone, and carry on once the birds have gone.
Do I have to tell my roofer if I think I have bats?
Yes, as early as you can, ideally before the survey visit. A roofer who knows in advance can look for signs, pause the plan and suggest an ecologist. A roofer who learns only after the ridge is off cannot undo the damage, and the roost may already be gone.