Soffit Box Bat Mitigation_Monmouthshire Garage Conversion

Garage Conversion – Bat Mitigation Installed

Proposed Works

The owners of this Monmouthshire building wished to convert a detached garage into an independent living area. Bats were already known to be inhabiting the main building next door to the garage, so a bat survey and a European Protected Species Licence was deemed necessary.

The Survey

While no evidence of bats was found in the preliminary roost assessment (although, swallow nests were recorded), the dusk activity surveys for bats recorded a single common pipistrelle using the building as a roost. This survey highlighted that the development of the building would mean the potential loss of a non-breeding common pipistrelle summer roost, or individual bats as well as the potential death or injury of bats that could be roosting during the development.


Pre-mitigation bat box

Before the works began, Schewegler 2F General bat boxes were set up on suitable trees within the site, to provide a compensatory roosting site during the development of the building. A licenced bat ecologist was on site to give advice to the contractors, to supervise the removal of soffit boxes, ridge tiles etc so as to minimise and avoid harming/disturbing the bats.


The mitigation plan ensured roosting opportunities were available for Pipistrellus species after the works were completed. External lighting was not installed on the northern elevation of the property in order to create a dark corridor. Often external lighting causes major disturbances to bat populations as they are forced to alter their foraging sites and their behaviour accordingly.

Roosting was provided underneath bargeboards on the northern elevation of the building and soffit bat roosts were also created that were positioned along the eastern and western elevations of the building.

Diagram of a soffit box
Soffit Box Bat Mitigation_Monmouthshire Garage Conversion
Soffit Box Bat Mitigation

In addition, the landscaping around the building and designing the garden will be enhanced in way that will provide suitable habitat for bats, such as encouraging night-flying invertebrates. A swallow nest box was also installed to encourage the swallows to return to the area.


Overall, the site was a successful demonstration of how mitigation for bats can be put in place easily and efficiently without major disturbances to the bats or the client, with the combined co-operation of the client, surveyors, and contractors.

Author: Ashely Dale

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