How a Bat Can Put a Stop to Your Loft Conversion

Louise Summers is Operations Director at Urban Wildlife, a wildlife consultancy who provide protected species surveys and mitigation solutions for construction projects, including many of the homes that we have created.

As our clients are often surprised by how drastically a creature as tiny as a bat can affect their plans, we asked Louise to answer some common questions about bats in residential developments.

Do I need a license to carry out works if there are bats in my house?

It is a criminal offence to deliberately harm bats or any other European Protected Species, which includes disturbing their habitats. And don’t think Brexit will change this – such protections are written into UK law.

The needs of bats and humans often clash in residential developments. You might want to convert your loft to make more room for your family, but if a bat family is there already, their needs will come first.

However, sometimes we can find ways to safely remove bats or provide them with replacement or alternative habitats, which is known as mitigation. To carry out mitigation, you need a mitigation license.

Mitigation must be overseen by an appropriately qualified ecologist or bat consultant, ideally someone who carries a license to capture and handle bats, or who is in training and therefore being supervised by an appropriately qualified person. Even if you receive a mitigation licensing and planning permission, bats must not be handled without a license to do so.

Beware that there are multiple tiers of licensing, some of which only permit an ecologist or consultant to survey bats but not handle them. Make sure whoever you hire carries the appropriate license for your needs.

How will I know if there are bats in my house?

There is no way to know whether you require a bat license to carry out your works and what mitigation techniques might be required until we identify the species using the site and how they are using it. This is where bat surveys come in.

There are 18 recorded species of bat in the UK, each with unique habitat preferences. Brown long-eared bats prefer attic spaces where they can warm up before they take fight, while tiny pipistrelles can roost beneath eaves and upturned tiles.

Bat roosts also come in many categories, from day roosts used as temporary shelter to maternal roosts hosting an entire family.

Mitigation for a daytime roost used by a single bat may not be as complex as dealing with a maternity roost. However, no bat roost can be disturbed without a license, so you development would be required to work around it.

Even if your site is not currently being used as a bat roost, you may still have to provide enhancement measures, especially if your development may cause a loss of foraging habitat.

You may even need to take bats into account if your house doesn’t exist yet. The National Planning Policy Framework suggests that new builds provide ecological improvements for the area, which may include bat habitats – especially out in the green belt.

Following our survey, we will cross reference our findings with guidance from the Bat Conservation Trust to attribute a conservation status to your building. This will determine what recommendations are necessary and whether you will require a license.

What methods of bat mitigation are available?

The appropriate method of mitigation is entirely dependent on the species of bat and how they are using – or could potentially use – your home.

Ideally, we will find a way not to disturb them at all by designing around their roosting area. For example, if they have chosen to make a certain corner of your loft, we could section off that area so it remains theirs after development.

If there is no way around the disturbance of their habitat, we may provide alternate roosting sites such as bat boxes or bat bricks which allow bats to enter into your cavity wall – a favourite for pipistrelles!

In some cases we have advised that separate, purpose built bat lofts are built in the garden or on top of garages.

When should I apply for a bat license for my development?

There is a strict timeline to bat surveys which can easily throw a spanner in your works if you are not careful. It is very important that you contact a bat consultant as early as possible so that you can incorporate the various deadlines into your plans.

At the quickest end of the scale (other than us not finding any evidence of bats or potential roosting sites) is a low impact license. This license is only suitable for some sites, usually those where the conservation status of the bat is not going to be affected.

The application process, once surveys are completes, is normally fairly short and can be completed within one month.

A low impact license gives a registered bat consultant full responsibility over ensuring that all necessary mitigations are understood and carried out by the contractors. This streamlines the process for Natural England.

At the other end of the scale is a full mitigation license. We apply for these when it is determined that your site is actively being used by bats and there is no way to avoid disturbing them.

Details of all mitigation efforts must be sent to Natural England for their approval. Once approved, we provide mitigation statements which are then included in the planning application for your development.

Only after planning permission is received can we apply for the mitigation license. The entire process takes up to three months, during which time no works can be carried out on site which may disturb bats or their habitat.

Failing to take these timings into account can significantly delay your project. While ground surveys (a superficial survey of the site to check for evidence of bats or its suitability as a habitat) can be performed any time of year, the emergence surveys required provide evidence to support a mitigation license can only be carried out between May and August.

If you miss this window, you have to wait until next year’s bat season to carry out the surveys and acquire the necessary licensing. When you get a license, your consultant may want to do another emergence survey to check the roost is off the same status if you have entered a new bat season. This is to ensure that the mitigation is still appropriate.

Even worse is not carrying out any surveys at all only for you to discover bats after the works have commenced. In such situations, the law requires that you immediately stop all construction work to carry out surveys and apply for a mitigation license.

Should this happen outside of bat season, your project will have to be put on hold until after the following may, when the relevant surveys have been completed and licenses achieved. Such a delay can be enough to sink a construction project.

Responsible architects – such as DGA – won’t attempt to cut corners. They will explain the need for consultants to their clients and bring them in early to minimise risk.

Any questions about bats? Call us now!

At Urban Wildlife Ltd., we’re always happy to answer any questions you have about bats and how they might affect your home development plans.

Please feel free to give us a call on 07500 011055 or email us at [email protected].

Advise can also be sought from the Bat Conservation Trust.

National Bat Helpline: 0345 1300 228
Email: [email protected]

Louise Summers