Current situation – SEPT 2022
For a bat roost:
- You do not need a certificate for bitumen 1F felt that has a non-woven, short fibre construction.
- You must include a certificate that proves the roofing membrane has passed a ‘snagging propensity test’ if you’re using a non-bitumen coated roofing membrane.
Details taken from Natural England website.
History of Bats and Modern roofing membranes
It has been reported the Bats were becoming entangled and dying in the mesh of Breathable Roofing Membranes.
In 2014 the BCT published results of the research they had supported into Bats and Breathable Roofing Membranes (BRMs).
The findings were clear:
BRMs should not be installed into a roof used by bats. Only bituminous roofing felt that does not contain polypropylene filaments should be used. For example bitumen felt type 1F, which is hessian reinforced
During summer 2015 Bat Conservation Trust (BCT) were made aware that a BRM manufacturing company was advertising one of its BRMs as ‘bat safe’.
The BCT lodged a complaint to the Advertising Standards Authority (ASA) in February 2016. The complaint was upheld and the ASA requested the company remove the claim from their website, which the company duly did in March 2016.
On 4th January 2016, the BCT confirmed the research project would continue.
In January 2019 the BCT issued the following advice to Bat groups.
Modern Roofing Membranes (formerly Breathable Roofing Membranes) currently are of a spun poly-bounded construction made up of long fibres, bats claws are sharp enough to pull these fibres loose, which entangle and ultimately kill bats.
BCT are aware the there is a new roofing membrane on the market called TLX Batsafe which claims it is safe for use in bat roosts, however BCT has not seen test data to verify this. Therefore the original advice stills stands, currently the only ‘bat safe’ roofing membrane is bitumen 1F felt that is a non-woven short fiibred construction.
It has also been noticed that on the manufacturer’s website: http://www.tlxinsulation.co.uk it says:
A summary of the manufactures testing is on the technical page of their website.
UPDATE – April 2019
BCT is aware the there is a new roofing membrane on the market called TLX Batsafe which claims it is safe for use in bat roosts. However, until the Statutory Nature Conservation Bodies (Natural England, Natural Resources Wales and Scottish Natural Heritage) are satisfied that this is indeed safe for use in bat roosts the original advice stills stands, currently the only ‘bat safe’ roofing membrane is bitumen 1F felt that is a non-woven short fibred construction.
This advice means that currently TLX Batsafe cannot be licenced for use in Bat Roosts
UPDATE – May 2019
The following was published in the June Bat group Bulletin from the BCT.
“4. Update on Modern Roofing Materials.
BCT, the SNCOs (NE, NRW and SNH) met with Emmanuel Essah of University of Reading on 15th May in a bid to move forward on the question of what constitutes a roofing membrane safe to use where bats are or could be present. Plans are underway to publish a methods paper that will allow the independent testing of membranes for this function.”
Update – 21st January 2020.
The following was published on the BCT website on 21/1/20.
“BCT, the SNCOs (NE, NRW and SNH) and academics from the University of Reading (Dr. Emmanuel Essah) and University of Leeds (Prof. Steve Russell) today submitted a paper titled ‘Method for evaluating the snagging propensity of roofing membranes in buildings by roosting bats’ – based on Stacey Waring’s (co-author) research.
Once published, this methods paper will allow the independent testing of membranes to answer the question of what constitutes a roofing membrane safe to use where bats are or could be present.
At this time therefore the original advice stills stands, currently the only ‘bat safe’ roofing membrane is bitumen 1F felt that is a non-woven short fibred construction.
All other membranes will now be referred to as ‘Non-Bitumen Coated Roofing Membranes‘ (NBCRMs) as this covers both breathable and non-breathable membranes and is the term used to describe them in the methods paper.”
Update – 27th May 2020
The following was published on the BCT website on 27/5/20.
“BCT, the SNCOs (NE, NRW and SNH) and academics from the University of Reading (Dr. Emmanuel Essah) and University of Leeds (Prof. Steve Russell) have received confirmation that their paper on Non-Bitumen Coated Roofing Membranes methods testing (based on Stacey Waring’s (co-author) research) has been published in Building Research and Information journal.
Titled ‘Method for evaluating the snagging propensity of roofing membranes in buildings by roosting bats’ this methods paper allows the independent testing of membranes to answer the question of what constitutes a roofing membrane with minimised risk to bats where they are or could be present.
Until these independent tests are completed and the results discussed with the relevant SNCO (NE, NRW, SNH), the original advice stills stands, currently the only ‘bat safe’ roofing membrane is bitumen 1F felt that is a non-woven short fibred construction.”
Update – 28th June 2021
The following was published in the Bat Group Bulletin on 28/5/21.
“The Non-Bitumen Coated Roofing Membranes steering group is now aware of the TLX independent testing methodology results for their “bat safe” membrane and concerns raised by Stacey Waring. The next NBCRMs steering group meeting is Tuesday 29th June which Stacey has kindly agreed to attend to fully discuss the issues so we can find a way to move this forward. Once this has happened the steering group can advise industry on next steps, the BCT website will be updated and we will include the update in a future Bat Group Bulletin. Until then the original advice still stands, currently the only roofing membrane safe to use where bats are present is bitumen 1F felt that is a non-woven short fibred construction.”
UPDATE – SEPTEMBER 2022
The NBCRMs steering group have been working to support the SNCO’s as the regulatory authorities to publish position statements on their respective websites on the issue of NBCRMs that have passed the snagging propensity test. Please see the Natural England (NE) website for their position statements in the link below: