Ecology and demolition: sequencing surveys before the machines

An ecology survey before demolition is not a box to tick after the contractor is appointed. Bats, nesting birds and badgers are protected by criminal law that applies to the person doing the work and to anyone who causes or permits it, and the moment a roof covering comes off is the moment the offence happens. A missed bat emergence window costs a full survey season, because those surveys can only be done between May and September.

Sequence the ecology and the demolition together, from the first programme. Sequence them separately and you will either break the law or wait a year.

Why demolition is the riskiest moment

Buildings hold roosts in places nobody looks at from the ground. Ridge tiles, hanging tiles, soffit boxes, lead flashing, gable mortar joints, cavity walls, bargeboards and the voids behind fascia boards are all used by bats, and most of them are only exposed once stripping starts.

Under the Conservation of Habitats and Species Regulations 2017 it is an offence to damage or destroy a breeding site or resting place of a European protected species, whether or not the animal is present at the time. A bat roost is protected when it is empty. That is the point most site managers have not absorbed, and it is the reason a licence is needed even for a roost that was last used in August.

Nesting birds sit under the Wildlife and Countryside Act 1981, which makes it an offence to damage or destroy a nest in use or being built. Badger setts are protected by the Protection of Badgers Act 1992, and interference with a sett needs a licence from Natural England.

A Protected Species Survey and any resulting licence require a suitably licensed ecologist. That is a legal requirement rather than good practice, and an AI-assisted draft is a starting point for that person rather than a substitute for them.

Surveys before anything is opened up

The sequence starts with a preliminary roost assessment, which can be done at any time of year. It is an external and internal inspection of the building, grading its suitability for roosting bats, and recording any evidence found.

What follows depends on that grading. The Bat Conservation Trust good practice guidelines set survey effort by suitability, with more emergence or re-entry surveys required as the suitability rises, and all of them confined to the active season. The detail of that effort is covered in bat emergence survey effort and roost suitability, and the practical consequence is simple arithmetic. A building graded as having high roost suitability, assessed in October, cannot have its survey effort completed until the following summer.

The bat survey results feed the licence application, and a European protected species mitigation licence can only be applied for once planning permission is in place, because Natural England has to consider the three derogation tests against a consented scheme. That ordering is fixed and it is the single biggest cause of programme surprise on conversion and demolition projects.

Barn conversions and agricultural buildings deserve their own look, because barn owls are protected while nesting and the survey and mitigation approach differs, as set out in barn owls in agricultural building conversions.

Soft strip under ecological supervision

Where a roost is present and a licence has been granted, the licence will usually require part of the demolition to be done by hand, under the supervision of the named ecologist.

In practice that means a sequence: the ecologist attends, the roofing contractor removes ridge tiles and then courses of tiles by hand rather than with a machine, the felt is lifted by hand and inspected, timbers are checked before removal, and only once the roost features are cleared is machine demolition allowed to start. Nothing is thrown down. Nothing is stacked over a feature not yet checked.

The licence may also fix the time of year for the destructive search, commonly avoiding the hibernation period, and may require the replacement roost provision to be in place and available before the original is lost.

Vegetation clearance has its own sequencing. Where work falls in the breeding bird season, a check by an ecologist immediately before clearance is the usual control, and the practicalities are covered in nesting bird checks before vegetation clearance.

The stop works protocol

Every demolition on a site with any ecological interest should have a written stop works protocol, and it should be in the site induction rather than in an appendix nobody reads.

A workable protocol says four things. What to stop for: any bat, any nest, any mammal, any unexpected void. What to do immediately: stop work in that area, do not touch the animal, cover the area loosely to protect it from weather and predation, and leave it undisturbed. Who to call, with a mobile number for the named ecologist and a fallback. And what happens next, which is that work in that area restarts only on the ecologist's written confirmation.

Give every operative a card with the number on it. The protocol fails because the one person who knew the name was on holiday, not because nobody understood the law.

Licence conditions during demolition

Mitigation licences carry conditions and the conditions are specific. Expect requirements covering the method of soft strip, the timing window, the attendance of the named ecologist and any accredited agents, the number and type of replacement roost features, where those features go and at what height and orientation, lighting restrictions during and after construction, and the keeping of records.

Lighting is the condition most often breached after completion. A licence that requires no illumination of a bat access point is undone by a security light fitted a year later, and the planning condition that secures the lighting design is what makes it stick. Make sure the licence mitigation and the approved lighting plan say the same thing.

Where habitat is lost as well as buildings, the scheme also has to deliver its biodiversity gain, and the metric baseline must be fixed before clearance. Clearing a site and then measuring it is not an option, since the baseline is taken as the habitat present immediately before the works, and a Biodiversity Net Gain Assessment based on a cleared site will not be accepted.

Records that discharge the condition

The planning condition securing ecological mitigation is usually discharged on evidence rather than on assertion. Keep the following from day one.

1. Dated photographs of each roost feature before, during and after the works.
2. The ecologist's site visit records, with dates, times and names.
3. The licence and any variations, with the annual return made to Natural England.
4. Toolbox talk and induction registers showing who received the stop works protocol.
5. Installation records for replacement roost features, with photographs showing position, height and orientation.
6. A completion statement from the named ecologist confirming the works were carried out in accordance with the licence and the approved method statement.

That last document is what councils ask for and what applicants most often cannot produce. Commission it as part of the ecologist's appointment rather than asking for it two years later.

What getting the order wrong costs

Three kinds of cost, and the first is the one people underestimate.

Delay is the common outcome. Discovering in September that a high suitability building needs three emergence surveys means a start on site the following July. On a site carrying finance costs that is the whole of the project contingency.

Legal exposure is the serious one. Offences under the 2017 Regulations and the 1981 Act are criminal, they can be committed by the contractor, the client and the person who gave the instruction, and ignorance of the roost is not a defence where reasonable steps were not taken. Natural England and the police do investigate reported destruction of roosts.

The third is reputational and procedural. A council that has seen a roost destroyed on one of your sites will apply conditions to the next one with a much shorter leash, and a licence application from an applicant with a history is a harder application.

An early ecological appraisal at feasibility stage costs a fraction of any of that.

Browse all 66 PlanScope report types to see which ecology documents a demolition or conversion scheme is likely to need.

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