What is a Preliminary Roost Assessment in London?

A Preliminary Roost Assessment in London is carried out to establish whether a site provides roosting sites or a suitable habitat for bats. It is the initial stage in the bat surveying process and is often requested by the local planning authorities to ensure that the new development will not affect bats in the surrounding area. Preliminary Roost Assessments in London can be undertaken during daylight hours and at any time of year.

What Happens Following a Preliminary Roost Assessment (PRA)?

If no evidence of bats is found on the proposed development site, then just the PRA is all that will be required from the planning authorities. However, if there is evidence of bats in the building or structure, the next stage is to have a bat emergence survey carried out. Please note, these can only be undertaken between May and September. An emergence survey records the level of bat activity. These are undertaken at night to allow our surveyors to monitor and record whether bats fly out of the building/structure or not. If no bats are recorded, then that’s all that required.

Alternatively, if bats are recorded entering and exiting the building then a further survey will be required to assess whether the bats will be affected by the proposed development. In the event that the development is identified as causing damage or disturb to roosting bats then a bat licence will need to be obtained in order to continue with the works.

However, if the development is able to proceed without any damage or disturbance to the areas where bats are roosting, then the development can proceed providing that you follow the recommended precautions.