Former Psychiatric Hospital Pavilion

Former Psychiatric Hospital Pavilion
1. Location

Geographical region: 
Yorkshire and the Humber
Name of council or planning authority : 
Kirklees Council
Name of consultant: 
Ecus Ltd
2. Type and description of building

Type and use of building (domestic house, commercial, industrial, etc.): 
Former pavilion
Approximate age (in years) or period of the building: 
Materials of the building (stone, brick, timber, etc.): 
brick and render walls, clay peg tile covered roof
Predominant landscape type around building (e.g. garden, urban, woodland, open farm fields): 
Woodland with football pitches
3. Details of proposed work and associated impacts

Type of impact to bats or roost: 
Roost modification
Date Timing of building/impact works (e.g. late spring, early summer) : 
Winter - early Spring 2013
Description of building works or impact: 
Re-development and extension of existing pavilion including partial re-roof. Blocking of all existing bat access points.
4. Description of roost (before mitigation)

Bat species found on site: 
Brown long-eared bat - (Plecotus auritus)
Age (estimate of how long the roost has been in use): 
At least 2 years
Size (estimate of number of individuals using the roost): 
Max count 22 brown long-eared bat and 1 common pipistrelle
Use Type of roosts (e.g. hibernation, spring gathering, maternity, nursery, swarming): 
day roost
Location in building: 
Within roof void for brown long-eared bat, crevice between roof beam and wall for common pipistelle
Aspect (direction facing): 
South facing for common pipistrelle, north-west to south-east orientated roof void
Description of immediate emergence environment in relation to the roost: 
Bats can emerge straight into broadleaved woodland
Roost substrate (e.g. brick, stone, wood, roofing felt): 
Roofing felt for brown long-eared bats
Evidence of insulation?: 
Height of roost above ground: 
2.5 m
Roof covering: 
Clay peg tile
Lighting levels inside roost (lux reading) - Day: 
5. Description of access (before mitigation)

Size of access: 
0.5 x 0.5 m open loft hatch for BLE. 5 cm x 1.5 cm slot in brickwork for common pipistrelle
Location in building: 
Loft hatch close to north-east wall, birckwork slot north-east elevation
Height of access points above ground: 
2.5 m
Aspect (direction facing): 
Main loft hatch access north-east facing. Common pipistrelle access in north-east elevation brickwork
6. Description of mitigation

Type of mitigation and compensation: 
Retaining existing roosts in refurbished buildings
Objective of mitigation: 
Main objective - to provide new access points into roof void and enhance roosting conditions within this space for brown long-eared bat. To retain common pipistrelle roost space.
Method to achieve objective: 
Bat access to the roof void took the form of six ‘Morris’ style bat access slates spread across the four roof slopes and three soffit access points installed in the front and rear elevations. Gaps were maintained between ridge tiles and the ridge board with blockages created approximately once per metre to prevent draughts. Holes cut in underfelt adjacent to ‘Morris’ slate and alongside the ridge beam to provide access into the ridge tunnel. Main pavilion building re-roofed with new and existing roof tiles, new bitumastic underfelt, new floor level insulation, wooden soffits and new guttering. The roof void will be retained for sole use of bats. Two Schwegler 1FD bat boxes and one Schwegler 1FS will be fitted to an oak tree to be retained adjacent to the pavilion.
How is success of mitigation to be measured: 
Retention of brown long-eared bat and common pipistrelle roost at pre-construction size
Drawings or plans of the project: 
7. Monitoring Data

Evidence of bat use post mitigation: 
23/05/2013 - Daytime inspection of roof void undertaken – approximately 20 fresh bat droppings seen beneath the south-eastern roof hip indicating the return of at least one brown long-eared bat to the roost following the re-roofing works. 26/08/2013 – Inspection of roof void recorded up to 300 fresh droppings in numerous locations on newly fitted glass-fibre insulation, mostly beneath the ridge beam. Findings indicate the return of the brown long-eared roost during the summer months. A dusk survey undertaken on the same date by recorded no bats emerging from the pavilion roof void, possibly indicating brown long-eared bats had subsequently abandoned the roost. 30/07/2014 – dusk emergence survey undertaken. 18 brown long-eared bats and 2 common pipistrelles were recorded emerging from various locations along the ridge and from two access tiles on the pavilion roof. Brown long-eared bats were observed roosting in various locations along the ridge beam immediately prior to the survey.
How long did it take for bats/signs of bats to appear?: 
2 months
8. Measures of success
Based on the objective of the mitigation do you deem the mitigation to have been successful?: 
Are there lessons from this project that you would like to highlight?: 
Renention of an existing roost in as close to it's original condition is likely to increase mitigation success Morris bat slates work and brown long-eared bats don't require a drop from access points
9. Photos (before and after)

Before – outside showing roost location: 
Before, Outside showing roost location - Roost 31/07/2014 - 7:23pm
Before – inside of roost: 
Before, Inside of roost  - Roost 31/07/2014 - 7:23pm
After – outside showing mitigation: 
After, Outside showing roost location - Roost 31/07/2014 - 7:23pm
After – inside showing mitigation: 
Before, Indise of roost - Roost 31/07/2014 - 7:23pm