New tiles being fitted onto the roof of the National Trust’s Oxburgh Hall in Norfolk have been adapted to stop bats sliding off.
Part of a massive re-roofing project at the historic manor house has included installing new black-glazed pan-tiles chosen to look the same as those used over two centuries ago, which had become weatherworn, cracked and damaged.
However, the black glaze on the new tiles was found to be too slippery for the property’s resident bats.
Looking for a solution, bat experts carried out tests which found that a coating of paint mixed with sand of different sizes enabled bats to grip with the tiny claws on their thumbs and feet and to climb easily to the safety of the roof top roosts.
Home to the Bedingfeld family for 500 years, Oxburgh Hall, a moated manor house, is nearing the end of a £6m project to reroof it as well as to replace chimneys and carry out other work.
Throughout the project measures have been taken to ensure that the bat populations which use the hall will still have access to their roosts after the work is finished.
Surveys found a total of six bat species flying close to the house but it is brown long-eared, common pipistrelle and soprano pipistrelle bats which roost in the building. The brown long-eared bats use attics and roof spaces, and all three species use crevices under roof tile, ridge tiles and lead flashing.
David White, the National Trust’s Project Manager, said: “Our survey carried out by local bat experts found numerous signs of brown long-eared bats in the attics and roof spaces right across the hall. There were signs of a maternity roost in the past but the current use has been as day and night roosts for numbers of brown long-eared and common pipistrelle bats.
“We have worked with bat experts to create a new roost in the nearby Bell Tower and installed bat boxes in the trees on the north terrace to provide alternative roosting places whilst the roof works takes place. Currently the bell in the Bell Tower can’t be rung, so not to disturb the bats.”
The builders have ensured there will be 32 new bat openings around the roof – some under the ridge tiles, some lower on the roof under pantiles, and others on the dormer windows. The roof tiles near the openings have been given the specially developed bat coating. Several of the roosts have carefully designed gaps in the roof lining to allow brown long-eared bats to get into the attics and roof voids.
A total of 14,000 new black-glazed pan-tiles are being used on the roofs at Oxburgh Hall. Historic records revealed that 50,000 pan-tiles and 800 ridge-tiles from Holland were needed in the 1770s to replace the originals. It is only the second roof restoration in Oxburgh Hall’s lifetime and the new tiles, sourced from the UK, are larger so fewer are needed.
The project to repair the roof started when a 150-year-old dormer window unexpectedly collapsed in 2016, exposing a structural weakness in the roof of the hall. As well as resolving the structural problems, the roof has been repaired, all 14 dormers that were added in the 19th century have been dismantled and rebuilt and the 27 distinctive chimneys, made with moulded hand-made bricks, have been rebuilt.
The project has been made possible thanks to National Trust supporters, as well as generous grants from the Heritage Stimulus Fund (part of the Culture Recovery Fund), the Wolfson Foundation and The National Lottery Heritage Fund.
David White continued: “This has been an ambitious project which now runs across every aspect of the roofscape. This major restoration will safeguard Oxburgh’s future. The project has certainly come with its challenges, as you’d expect for a 500-year-old building surrounded by a moat. However, it’s rewarding to see the craftsmanship and roofline gradually being revealed, as we inch closer to completion.”
Oxburgh Hall is currently open to visitors and the restoration work is due to be completed in early 2022.
Header image: Mike Hodgson/National Trust.