Overview
BSG Ecology assisted Cadw with their proposals for the renovation of Tretower Court Barns, Brecon. The Barns supported a small number of roosting bats, including species of high conservation status. Thorough survey work was required to address the challenges faced in retaining a space for bats alongside the proposed new use of the building. The Barns were successfully renovated in 2022, and now operate as a visitor centre and café in addition to accommodating a separate space for roosting bats.
Challenge
Cadw proposed the renovation of ‘The Barns,’ adjacent to Tretower Court, Brecon, to create a visitor centre and café. The original building was built in the 15th Century: due to extensions and changes of use during the 17-19th Centuries only a gable wall of the original structure survived, complete with blocked windows, a fireplace and a patch of painted plaster.
The Barns have recently been used as a store for Tretower Court. They are stone built with an overlapping stone-tiled gabled roof. The wooden roof frame includes traditional mortise joints between truss timbers, and batons are supported by purlins, which provided gaps between the timbers and tiles suitable to support crevice roosting bats. A stone chimney, capped off at roof level, is present in one of the Barns which provided a further enclosed, darkened space. Prior to restoration works commencing, there were numerous opportunities for free-flight access by bats and birds into the Barn interior and the structure offered abundant roosting opportunities for crevice and cavity roosting bats (both internally and externally around woodwork and within the stone walls) and free-hanging bats (at the roof apex and within the capped stone chimney).
Desk-study data and anecdotal evidence from the Custodian indicated that Tretower Court was known to support small maternity colonies of lesser horseshoe bat within its conserved fireplace and stove chimneys, and grain stores. BSG Ecology commenced survey work in 2017 (including a close inspection of accessible cavities and interior spaces, and dusk emergence survey) followed by further survey using infrared and thermal imaging cameras in 2018. The work confirmed use of the Barns by small numbers of lesser and greater horseshoe bat, as well as brown long-eared bat, Natterer’s bat and common pipistrelle bats.
The proposed works would require the exclusion of bats from publicly accessible interior spaces, and also allow sealing and weather proofing of eroding block and roof-work. In the absence of mitigation, these actions would result in the loss of roosting opportunities for at least five species of bat.
Solution
BSG Ecology worked closely with Cadw and their appointed architects Garner Southall and DB3 Architecture throughout the project to help ensure the approach to renovation delivered against Cadw’s brief, whilst retaining suitable roosting opportunities for bats.
The solution was to provide a bat loft that would separate the publicly accessible internal area from the bat roost. The loft was designed to retain free-flight access by bats and provide a varied and functional internal space containing a ‘hot-box’ for lesser-horseshoe bats, several artificial cavities and crevices, and access to existing blockwork at the apex of the chimney breast.
Outcome
A bat licence for the works was secured in 2019 and a full renovation, along with the installation of the integrated bat ‘loft’, was completed in June 2022. Gareth Lang attended the official opening of the Barns shortly after completion, and provided a contextual presentation on the challenges faced in retaining a space for bats within the new public space. Post-completion monitoring to determine the success of the new bat loft will commence in spring 2023.
Tretower Court is open to the public daily between April and October inclusive, with reduced opening hours through the winter. Y Bwytty Bach is located within the northern part of the Barn, and is now open for lunch and refreshments, and evening fine-dining.