Bats and Breathable Roofing Membranes

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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 it says:

BatSafe is intended for areas where there is evidence of bats and should not be used where roosts are found.

A summary of the manufactures testing is on the technical page of their website.

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