Preliminary Bat Roost Assessment - Ref: R2747/a - Wokingham ...
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The Gate House
Sonning Lane
Sonning
Berkshire
RG4 6ST
Preliminary Bat Roost Assessment
Ref: R2747/a
April 2021
1 Diesel House, Honey Hill, Wokingham, Berkshire RG40 3BL
Telephone: 0118 3271810 Mobile: 07979 403099 E-mail: info@wenman-ecology.co.uk
www.wenman-ecology.co.uk
John Wenman Ecological Consultancy LLP is a limited liability partnership registered in England and Wales with registered number OC339057.
Registered office: 100 New Wokingham Road, Crowthorne, RG45 6JP where you may look at a list of members’ names.
1 EXECUTIVE SUMMARY .................................................................................................. 3
2 INTRODUCTION .............................................................................................................. 4
2.1 Background .................................................................................................................................. 4
2.2 Legislative Background ................................................................................................................ 4
2.3 Site Location and Context ............................................................................................................ 5
3 SURVEY METHODOLOGY.............................................................................................. 6
3.1 Building Inspection ....................................................................................................................... 6
3.2 Survey Constraints....................................................................................................................... 6
4 SURVEY FINDINGS ......................................................................................................... 7
4.1 Introduction .................................................................................................................................. 7
4.2 External Survey............................................................................................................................ 7
4.3 Internal Survey ............................................................................................................................. 7
5 DISCUSSION AND RECOMMENDATIONS .................................................................... 9
5.1 Assessment of Bat Roost Potential .............................................................................................. 9
5.2 Impact of Proposals and Recommendations ............................................................................... 9
5.3 Precautionary Measures .............................................................................................................. 9
6 REFERENCES ............................................................................................................... 11
APPENDIX 1 - SITE PHOTOGRAPHS ................................................................................... 12
APPENDIX 2 – PRELIMINARY BAT ROOST ASSESSMENT PLAN ................................... 16
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1 EXECUTIVE SUMMARY
1.1.1 John Wenman Ecological Consultancy LLP was commissioned by Mr David Bates to
undertake a survey for the presence of bats at The Gate House on Sonning Lane in
Sonning, Berkshire. The survey was commissioned in relation to a planning
application seeking consent for the addition of three dormer windows and external
access into the hayloft.
1.1.2 A survey of the interior and exterior of the property was undertaken on the 30th
March 2021 by two ecologists registered under Natural England Bat Survey Class
Licences CL18 and CL17 respectively.
1.1.3 The building inspection found no signs of bats. It did highlight occasional gaps under
uneven or slightly raised clay roof tiles that, in conjunction with the new roof lining
and insulation inside the hayloft (renovated in October 2020), present new roosting
opportunities to crevice-dwelling bats such as pipistrelle (Pipistrellus spp.) and/or
small Myotis species.
1.1.4 The potential roost features in the roof are new and consequently considered
unlikely to currently support roosting bats, but in the future could provide suitable
roosting opportunities to the aforementioned crevice-dwelling bat species.
1.1.5 The renovated roof will continue to provide the same roost features (i.e., gaps under
uneven or slightly raised clay tiles) after the addition of three dormer windows and
thus the continued ecological functionality for roosting bats will remain
uncompromised.
1.1.6 It remains possible that in the future, bats may utilise the roost features (i.e., gaps
under uneven or slightly raised clay tiles) and therefore, precautionary measures
should be adopted prior to dormer construction as set out in Section 5.3.
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2 INTRODUCTION
2.1 Background
2.1.1 John Wenman Ecological Consultancy LLP was commissioned by Mr David Bates
to undertake a survey for the presence of bats at The Gate House on Sonning Lane
in Sonning, Berkshire.
2.1.2 The survey was commissioned in relation to a planning application to be lodged with
Wokingham Borough Council seeking consent for the addition of three dormer
windows and external access into the hayloft.
2.2 Legislative Background
2.2.1 All British bat species are fully protected by the Wildlife & Countryside Act 1981 (as
amended) and by the Conservation of Habitats and Species Regulations 2017
(‘Habitat Regulations’) (as ammended). In summary, the legislation combined
makes it an offence to:
• Damage or destroy a breeding site or resting place or intentionally or
recklessly obstruct access to a structure or place used for shelter by a bat;
• Deliberately, intentionally or recklessly disturb bats; in particular, any
disturbance which is likely to impair the ability of bats to survive, breed or
reproduce or nurture their young; or in the case of hibernating or migrating
bats, to hibernate or migrate; or to significantly affect the local distribution or
abundance of the species; and
• Deliberately kill, injure or take any bat.
2.2.2 The government’s statutory conservation advisory organisation, Natural England, is
responsible for issuing European Protected Species licences that would permit
activities that would otherwise lead to an infringement of the Habitat Regulations. A
licence can be issued if the following three tests have been met:
• Regulation 55(9)(a) - there is “no satisfactory alternative” to the derogation;
• Regulation 55(9)(b) - the derogation “will not be detrimental to the
maintenance of the population of the species concerned at a favourable
conservation status in their natural range”; and
• Regulation 55(2)(e) - the derogation is for the purposes of “preserving public
health or public safety or other imperative reasons of overriding public
interest, including those of a social or economic nature and beneficial
consequences of primary importance for the environment”.
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2.2.3 Local authorities have a statutory duty under Regulation 7(3e) of the Habitat
Regulations to have regard to requirements of the Habitats Directive in the exercise
of their functions. The Council must therefore consider and determine whether
these three tests are likely to be satisfied by applications where survey findings
show that European Protected Species licensing is necessary before granting
planning permission.
2.2.4 European Protected Species (EPS) mitigation licence applications can be submitted
once all necessary planning consents have been granted and Natural England aim
to issue a licence decision within 30 working days.
2.2.5 Licensable projects affecting small numbers of seven commonly occurring species
occupying roosts of low conservation importance may fall under the remit of the Bat
Mitigation Class Licence (Low Impact) (WML-CL21). The Class Licence permits
‘Registered Consultants’ or accredited agents appointed by them to carry out
licensable operations on site on behalf of clients following the registration of sites
with Natural England at least 15 working days before the work is due to start.
2.2.6 Survey data supporting EPS licence applications or the registration of the site under
the Bat Mitigation Class Licence (WML-CL21) must be up to date i.e. have been
conducted within the current or most recent optimal survey season i.e. May to
August. Therefore, if surveys show bats are present and licensable work is delayed
until during or after the next survey season, updated surveys will be required to
support an application or site registration.
2.3 Site Location and Context
2.3.1 The Gate House is situated on the eastern side of Sonning Lane in Sonning,
Berkshire (OS grid reference: SU 75599 75343).
2.3.1 The property is set in the village of Sonning on the edge of the suburban sprawl of
Reading. The immediate surroundings are composed of large residential properties
and Reading Blue Coat School, which include broadleaved woodland, parkland and
traditional orchard Priority Habitats. Ali’s Pond Local Nature Reserve is just over
150m to the south and the River Thames – an important wildlife corridor – is
approximately 330m to the northwest of the property. These nearby habitats provide
high quality commuting and foraging opportunities for bats roosting locally.
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3 SURVEY METHODOLOGY
3.1 Building Inspection
3.1.1 A survey of the interior and exterior of the property was undertaken on the 30th
March 2021 by two ecologists registered under Natural England Bat Survey Class
Licences CL18 and CL17, respectively.
3.1.2 The survey was undertaken with the aid of binoculars and a high power (1 million
candle power) torch and looked for features that could offer potential roosting sites
following standard survey guidelines (Collins 2016; Mitchell-Jones 2004; Mitchell-
Jones & McLeish 2004).
3.1.3 The following may indicate the presence of a bat roost within a building:
• Bat droppings (these can be found externally, especially in sheltered areas
such as window sills, underneath roost entrances or internally within a roof
space);
• Piles of insect remains e.g., moth wings (these may be indicative of regular
feeding sites used by species such as brown long-eared bat);
• Staining at roost entrances or within the roost (urine and oil from fur can
leave stains on timbers when bats are gathered for long periods); and
• Bats (live or dead).
3.1.4 Residential buildings may offer potential roosting sites in a number of locations,
favoured locations include:
• Under roof, ridge and hip tiles, especially when loose or lifted tiles are
present, or sections of mortar are missing;
• Under sections of raised lead flashing;
• Beneath lifted barge boards;
• At the gable ends – access is typically gained at the roof apex via gaps in the
soffits or under roof tiles;
• At the eaves – gaining access via gaps between the soffits and wall; and
• Within an enclosed roof space – long-eared bats (Plecotus spp.) for
example, will often cluster at the ridge beam.
3.2 Survey Constraints
3.2.1 There were no significant constraints to the survey as full access was available to
the interior and exterior of the property.
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4 SURVEY FINDINGS
4.1 Introduction
4.1.1 Photographs of the property are presented in Appendix 1 and a plan of the external
and internal survey findings with associated target notes is shown in Appendix 2.
The survey findings from the exterior and interior of the property are described as
follows:
4.2 External Survey
4.2.1 The detached house was ‘L’-shaped with a hipped roof (renovated in October 2020)
and a mixture of traditional and modern brick walls (Photographs 1 & 2). The roof
had been completely retiled with overlapping clay tiles, three rooflight windows had
been installed and the ridge and hip tiles were all newly mortared (Photographs 3
& 4; Target notes 1 & 2). Occasional gaps were present where roof tiles were
uneven or slightly raised and these had potential to be exploited by crevice-roosting
bats in the future (Photograph 5; Target note 3).
4.2.2 The roof renovation included the entrance to the hayloft, which had new ridge and
verge mortar and tight timber cladding (Photograph 6; Target note 4). A gap ran
along the eaves and a hole in the brickwork was noted (Photographs 7 & 8; Target
notes 5 & 6). There were several small, hipped bay windows and a front porch
(Photograph 9).
4.2.3 No evidence of bats was visible on the exterior of the property at the time of the
survey.
4.3 Internal Survey
4.3.1 The hayloft was accessible through an external entrance via a ladder (Photograph
10; Target note 7). The space had an approximate floor-to-ridge height of 3.5
metres and was of traditional ‘cut and pitch’ roof construction with queen posts and
collar beams (Photograph 11). As part of the roof renovation, the roof had been
lined with breathable roofing membrane and insulated with hard form boards and
spray foam (Photographs 12 & 13; Target notes 8 & 9). The roof timbers were
generally tight against the chimney stacks and spray foam insulation sealed any
gaps (Photograph 14 & 15; Target note 10). Hard foam insulation extended right
down to the wall plate along the eaves (Photograph 16; Target note 11). The floor
was boarded with timber planks and the western area was used for miscellaneous
storage purposes (Photographs 17 & 18; Target notes 12 & 13). There was a
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raised, covered water tank beneath one of the three new rooflight windows
(Photographs 19 & 20).
4.3.2 No signs of roosting bats were found during the internal inspection of the property.
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5 DISCUSSION AND RECOMMENDATIONS
5.1 Assessment of Bat Roost Potential
5.1.1 A personal communication with the client revealed that prior to the recent renovation
(in October 2020), the hayloft roof was unlined and consequently unlikely to have
provided roosting opportunities for crevice-dwelling bats in the past.
5.1.2 The building inspection found no signs of bats roosting in the property. It did
highlight occasional gaps under uneven or slightly raised clay roof tiles that, in
conjunction with the new roof lining and insulation inside the hayloft, present new
roosting opportunities to crevice-dwelling bats such as pipistrelle (Pipistrellus spp.)
and/or small Myotis species.
5.1.3 The potential roost features in the roof are new and considered unlikely to currently
support roosting bats, but in the future could provide suitable roosting opportunities
to the aforementioned crevice-dwelling bat species.
5.2 Impact of Proposals and Recommendations
5.2.1 The proposals include the construction of three dormer windows into the roof on the
southern elevation of the property. The renovated roof will continue to provide the
same roost features (i.e., gaps under uneven or slightly raised clay tiles) after the
addition of three dormer windows and thus the continued ecological functionality of
the roof as a potential roosting site bats will remain uncompromised.
5.2.2 The property showed no signs of occupation by roosting bats and the new external
roost features were unlikely to currently support roosting bats. However, bats are
highly mobile and it is possible that in the future, individuals may utilise these new
roost features (i.e., gaps under uneven or slightly raised clay tiles) and it is possible
that the work could therefore lead to the disturbance of bats in the roost and
therefore, precautionary measures should be adopted prior to dormer construction
as set out in Section 5.3 below.
5.3 Precautionary Measures
5.3.1 In order to confirm the absence of roosting bats, the new potential roost features
(i.e., gaps under uneven or slightly raised clay tiles) will be closely inspected from a
scaffold or platform with an endoscope prior to work commencing. The removal of
roof tiles will begin only once the licensed ecologist has confirmed that there
continues to be no signs of roosting bats.
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5.3.2 The licensed ecologist will brief the building contractors on bats, their roosting sites
and the legislation protecting bats and their roosts, signs indicating the presence of
bats, and what to do in the unlikely event that bats are discovered during the course
of the work. Specifically, if bats are discovered then the work must stop immediately
and a licensed ecologist should be called to site to attend to the bat(s) and provide
further advice on how to proceed; work should only recommence once further written
advice has been received. At this point, a European Protected Species Mitigation
Licence may be required to permit the work to continue lawfully.
The Gate House, Sonning Lane, Sonning - Preliminary Bat Roost Assessment (R2747a).doc
- 10 -6 REFERENCES
Collins, J. (ed.) (2016). Bat Surveys for Professional Ecologists – Good Practice
Guidelines 3rd Edition. Bat Conservation Trust, London.
Mitchell-Jones, A. J. (2004). Bat Mitigation Guidelines. English Nature,
Peterborough.
Mitchell-Jones, A. J. & McLeish, A. P. (2004). Bat Workers’ Manual (3rd Edition).
JNCC, Peterborough.
The Gate House, Sonning Lane, Sonning - Preliminary Bat Roost Assessment (R2747a).doc
- 11 -APPENDIX 1 - SITE PHOTOGRAPHS
1. The Gate House viewed from southeast. 2. The Gate House viewed from south.
3. Rooflight window (southern elevation). 4. New hip mortar (southern elevation).
5. Occasional gaps under clay roof tiles 6. Entrance to hayloft (eastern elevation).
(southern elevation).
The Gate House, Sonning Lane, Sonning - Preliminary Bat Roost Assessment (R2747a).doc
- 12 -7. Gap running along eaves (southern 8. Hole in brickwork at eaves (eastern
elevation). elevation).
9. Bay windows and porch roof (eastern/south 10. Entrance into hayloft.
elevations).
11. Eastern end of hayloft. 12. Breathable roofing membrane behind
insulation.
The Gate House, Sonning Lane, Sonning - Preliminary Bat Roost Assessment (R2747a).doc
- 13 -13. Hard foam insulation and spray foam. 14. Tight timbers and spray foam around
western chimney stack.
15. Spray foam around eastern chimney stack. 16. Hard foam down to wall plate at eaves.
17. Boarded floor. 18. Miscellaneous storage.
The Gate House, Sonning Lane, Sonning - Preliminary Bat Roost Assessment (R2747a).doc
- 14 -19. Raised water tank. 20. New rooflight window.
The Gate House, Sonning Lane, Sonning - Preliminary Bat Roost Assessment (R2747a).doc
- 15 -APPENDIX 2 – PRELIMINARY BAT ROOST ASSESSMENT PLAN
The Gate House, Sonning Lane, Sonning - Preliminary Bat Roost Assessment (R2747a).doc
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