Astrid Madsen
Bats are a protected species in both NI and ROI. This means you cannot disturb any place bats may be using for shelter or protection, whether or not bats are present, otherwise you will be committing an offence.
The only exception is if a bat enters your living quarters; out of immediate necessity can remove it (scratch resistant gloves should be worn and you need to capture it with care, preferably in a box, before releasing it outside at a height). If you suspect they are present in your building you should alert the authorities.
In ROI that means contacting the National Parks and Wildlife Service (NPWS); they will provide free information on how to carry out building works without disturbing the bats. They may ask that you time it so that breeding bats are not disturbed at their most vulnerable and you may have to leave access points open so they can continue to use the roost following the completion of the build. For more complex jobs a Conservation Ranger may need to visit the premises and provide a solution; if none is found you will need to apply for a derogation license.
In NI contact the NIEA Natural Heritage section before starting any work, their advice is also free. You may need a license to carry out your renovation plans; the license will only be issued to a recognised ‘bat expert’. The Northern Ireland Bat Group can provide information and may carry out an initial inspection for you.
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