Why a loft conversion can matter
Bats and their breeding sites or resting places are legally protected. Relevant offences include damaging or destroying those places, obstructing access to them and unlawfully disturbing bats. Roof work, loft insulation and alterations to lighting can therefore need ecological consideration as well as planning and building-regulations approval. [2]
Natural England's planning advice identifies buildings with features such as gaps, cracks, crevices and suitable roof spaces as circumstances where a survey may be needed. Nearby habitat and the nature of the work also matter. A new dormer is not the only possible source of impact: changing access into a roof can be significant too. [1]
Start with a competent ecological assessment
Ask a suitably experienced ecologist to establish the roof's potential and the information needed for the proposed work. The assessment should be appropriate to the species and circumstances, with any necessary survey licence in place. A normal measured survey or a builder's inspection is not a substitute for that assessment. [1] [2]
Natural England advises councils not to treat an absence of local records as evidence that bats are absent. Equally, a precautionary concern does not prove that a roost exists. The purpose of the survey is to establish evidence rather than make either assumption. [1]
Surveys can affect the programme
Survey timing depends on the information needed and the appropriate season. An initial inspection may identify a need for further work, so do not assume that a single visit at any time of year can answer every question. Discuss timing before fixing the application and construction dates. [1]
Where relevant, survey information should establish the species present, the population and use of the site, and the importance of any roost or associated habitat. The assessment then needs to explain the effect of the proposed development, not simply report that bats have been seen nearby. [1]
What happens if bats are present?
The first design question is whether harm can be avoided. The ecologist may need to advise on changes to the scheme or the way and timing in which it is carried out. Any required mitigation should be coordinated with the roof design, access features and lighting proposals. [1]
Where work would otherwise commit a protected-species offence and cannot avoid the impact, a Natural England licence may be necessary. Planning permission is not that licence, and the presence of bats does not mean that a licence will automatically be granted. Establish the licensing requirements before the affected work begins. [2] [1]
What if bats are found during the work?
Stop work that could disturb or harm them or affect the suspected roost, keep access unobstructed and contact a suitably qualified ecologist. Do not move bats or close an entrance simply to keep the programme on schedule. This is a precaution to avoid the offences described in the official protection guidance. [2]
Keep the ecological assessment, any licence and the agreed working measures with the construction information. Make sure the people changing the roof know the relevant restrictions before they start, rather than leaving the report only in the planning file. [1] [2]