DSP Structural Engineers
Pucks Cottage Puckaster Lane Niton Undercliff Ventnor PO38 2LZ
STRUCTURAL ENGINEER’S REPORT
CLIENT CONSULTING ENGINEER
Roland Toombs DSP Structural Engineers 2 Havant Road Emsworth PO10 7JE 01243 882937 [email protected] www.dspstructuralengineers.com
Issue Status
Rev Date Description By Check 12389-SER-01 # 01/12/20 First Issue DIS FMS
DSP Structural Engineers 12389-SER-01 Pucks Cottage
TABLE OF CONTENTS
page
1 BRIEF ...... 3
2 VISIT ...... 3
3 SITE ...... 3
4 STRUCTURE ...... 4
5 INSPECTION ...... 4
6 DISCUSSION ...... 5
7 CONCLUSIONS ...... 7
APPENDIX A - LOCATION PLAN
APPENDIX B - PHOTOGRAPHS
APPENDIX C – EXTRACT FROM GEOLOGICAL SURVEY
APPENDIX D – THE UNDERCLIFF OF THE ISLE OF WIGHT
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DSP Structural Engineers 12389-SER-01 Pucks Cottage
1 BRIEF
1.1 DSP Structural Engineers were appointed by Roland Toombs to provide a Structural Engineers Report on Pucks Cottage, Puckaster Lane, Ventnor, PO38 2LZ.
1.2 The inspection was limited to a visual inspection, subject to access being available. We have not moved furniture, lifted floor coverings, or made exploratory holes unless noted in the report.
1.3 Our inspection of the property did not include any parts of the structure which are inaccessible and we are therefore unable to report that the structure is free from defects other than those observed.
1.4 No guarantee can be given against the presence of rot, disease, beetle infestation or other defects within the timber of the property.
1.5 No responsibility is accepted to any other third party for the whole or part of the contents of this report.
1.6 For the purposes of this report, unless otherwise stated, the front elevation is considered to be that with the main entrance door and all references to left and right are given as if viewing a plan of the property with the front elevation located to the bottom, and the rear elevation located to the top of the plan.
2 VISIT
2.1 The property was inspected by Mr DI Shields, B.Sc., M.Sc., C.Eng., M.I.C.E., M.I.Struct.E. on the 1st December 2020.
3 SITE
3.1 The site of the property is located as shown in Appendix A.
3.2 The site is steeply sloping in the area of the property, down from the rear.
3.3 An extract from the geological survey is attached in Appendix C. The shaded area shows that the area of the property is on an historic area of landslip known locally
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DSP Structural Engineers 12389-SER-01 Pucks Cottage
as the ‘Undercliff’. The Undercliff extends for a distance of 12km from Blackgang in the west to Bonchurch in the east, including the town of Ventnor and the villages of Bonchurch, St Lawrence, Niton and Blackgang.
3.4 It should be noted that the area immediately to the east of the property and the former road along the shore to the west have been lost in landslips. The area immediately to the south has also suffered from relatively recent landslip movement in 1994/1995 when part of the garden was lost.
3.5 A comprehensive account of the Undercliff area, published by the Isle of Wight Council, is attached in Appendix D.
3.6 There were mature trees located around the property, on the front and right hand boundaries.
4 STRUCTURE
4.1 The property is a single storey house, judged to have been constructed around 1970.
4.2 The main walls are of loadbearing masonry and the property has a pitched and tiled roof structure.
4.3 The property has suspended timber floor.
4.4 It is proposed to extend the property with a single storey extension to the rear. A drawing showing the proposed extension is attached in Appendix E.
5 INSPECTION
5.1 Externally some general signs of historic movement and distortion were noted.
5.2 Minor cracking was noted to the external masonry.
5.3 A slight lean was noted to the chimney.
5.4 On the front elevation a vertical crack was noted below the front porch window.
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DSP Structural Engineers 12389-SER-01 Pucks Cottage
5.5 On the left elevation the small side addition had cracked and moved away from the side wall of the property. This appears to be a newer extension.
5.6 On the right elevation deterioration was noted to the window lintels.
5.7 Internally some general signs of historic movement and distortion were noted with sloping floors and distortion of door openings. Minor cracking to the internal walls was noted throughout the property.
5.8 In the lounge right-hand side, slight cracking was noted to the door opening. The floor sloped down to the right-hand side.
5.9 In the hall at front, there was a vertical crack under the front window by the entrance door with cracking around the porch entrance. Floor sloped down to front and porch door was stiff to open. There was a vertical crack above the door into the rear lounge with distortion of doorframe down towards rear. There was a crack across the hall ceiling at the bottom of the stairs.
5.10 Cracking was noted in the rear room and to the window in the pantry
5.11 In the bedroom in the roof space the floor sloped down to the front. A partial examination of the roof structure was made through the access hatches in the roof space. No significant defects were noted.
6 DISCUSSION
6.1 It is noted that the property is located on an area of old landslip known as the Undercliff. From the information contained in appendix D, it is noted that while areas of the Undercliff can be liable to sudden landslip causing roads to be abandoned and buildings to be demolished, other areas have remained stable.
6.2 The property currently appears stable and no sign of any significant foundation movement, due to either landslip or subsidence, was noted. The movement and distortion noted throughout the property is judged most likely to be due to local historic settlement of the foundations.
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DSP Structural Engineers 12389-SER-01 Pucks Cottage
6.3 The area is however at some risk of future movement and this is believed to have occurred relatively recently to the south of the building. Should prolonged and excessive rainfall occur then there is a risk that landslip damage to the property may occur.
6.4 The proposed extension, as shown on the drawing attached in Appendix E, would not however adversely affect the stability of the property. No special foundations are judged necessary for the new extension, other than those required for the local soil conditions under the building.
6.5 Some cracking was noted internally and on the external elevations. This would however appear to be due to normal shrinkage or thermal movement of the walls, rather than to any significant foundation movement.
6.6 Slight movement has occurred to the addition on the left hand elevation. This is judged most likely due to local settlement of the foundations, relative to the main part of the property. It is considered likely the addition has been constructed fairly recently. The foundations therefore may not have been taken to a suitable depth. Possible reconstruction of this area may be required if movement continues.
6.7 It is recommended that a CCTV survey of the foul and roof drainage should be carried out and any defects rectified.
6.8 It would be prudent to survey the condition of the wall ties to ensure that they are in a reasonable condition. We would note however this is a precautionary recommendation and that inspection showed there are no current indications of wall ties failure.
6.9 The chimney above roof level was noted to have deteriorated and had taken on a slight lean. No urgent action is judged necessary however future remedial works are likely to be required.
6.10 Deterioration was noted to the window lintels on the right hand side. This is judged most likely due to corrosion of the steel reinforcement. Local repair is required. Replacement of the lintel may be required if the damage worsens.
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DSP Structural Engineers 12389-SER-01 Pucks Cottage
6.11 It should be noted that, as in all properties of this age and type, minor differential movements may be expected to occur from time to time requiring remedial decoration work inside the property or minor external repairs.
6.12 The roof structure was not fully examined as part of this survey and therefore no comments can be made as to its condition and structural adequacy.
7 CONCLUSIONS
7.1 The property currently appears stable and no sign of any significant foundation movement, due to either landslip or subsidence, was noted.
7.2 The area is however at some risk of future movement and this is believed to have occurred relatively recently to the south of the building. Should prolonged and excessive rainfall occur then there is a risk that landslip damage to the property may occur.
7.3 The proposed extension, as shown on the drawing attached in Appendix E, is however acceptable and would not adversely affect the stability of the property. No special foundations are judged necessary for the new extension, other than those required for the local soil conditions under the building.
7.4 It is recommended that a CCTV survey of the foul and roof drainage should be carried out and any defects rectified.
D I Shields B.Sc., M.Sc., C.Eng., M.I.C.E., M.I.Struct.E.
For DSP Structural Engineers
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DSP Structural Engineers 12389-SER-01 Pucks Cottage
APPENDIX A - Location Plan
DSP Structural Engineers Contract Job Ref. CONSULTING CIVIL & STRUCTURAL ENGINEERS Pucks Cottage 12389
2 HAVANT ROAD Calc. by Date Checked by Drg Ref. EMSWORTH PO10 7JE DIS 01/12/20 Tel: 01243 882937 Email: [email protected] Part of Sheet No. Structure www.dspstructuralengineers,com Location Plan SER1
DSP Structural Engineers 12389-SER-01 Pucks Cottage
APPENDIX B - Photographs
DSP Structural Engineers 12389-SER-01 Pucks Cottage
Photo No. 01 – Front elevation of the property.
Photo No. 02 – Rear elevation of the Property
DSP Structural Engineers 12389-SER-01 Pucks Cottage
Photo No. 03 – Left elevation of the property.
Photo No. 04 – Cracking to left hand addition.
DSP Structural Engineers 12389-SER-01 Pucks Cottage
Photo No. 05 – Internal cracking.
Photo No. 06 – Internal cracking.
DSP Structural Engineers 12389-SER-01 Pucks Cottage
Photo No. 07 – Internal cracking.
Photo No. 08 – Internal cracking.
DSP Structural Engineers 12389-SER-01 Pucks Cottage
Photo No. 09 – Internal cracking.
Photo No. 10 – Room in roof space.
DSP Structural Engineers 12389-SER-01 Pucks Cottage
APPENDIX C – Extract from Geological Survey
DSP Structural Engineers Contract Job Ref. CONSULTING CIVIL & STRUCTURAL ENGINEERS Pucks Cottage 12389
2 HAVANT ROAD Calc. by Date Checked by Drg Ref. EMSWORTH PO10 7JE DIS 01/12/20 Tel: 01243 882937 Email: [email protected] Part of Sheet No. Structure www.dspstructuralengineers,com Extract From Geological Survey SER2
DSP Structural Engineers 12389-SER-01 Pucks Cottage
APPENDIX D – The Undercliff of the Isle of Wight
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The Undercliff of the Isle of Wight
Aguide to managing ground instability managing ground instablity part 1.qxp 13/08/2007 10:39 Page 1
The Undercliff of the Isle of Wight
Aguide to managing ground instability
Dr Robin McInnes, OBE Centre for the Coastal Environment Isle of Wight Council United Kingdom managing ground instablity part 1.qxp 13/08/2007 10:39 Page 2
Acknowledgements
About this guide This guide has been prepared by the Isle of Wight Council's Centre for the Coastal Environment to promote sustainable management of ground instability problems within the Undercliff of the Isle of Wight. This guidance has been developed following a series of studies and investigations undertaken since 1987. The work of the following individuals, who have contributed to our current knowledge on this subject, is gratefully acknowledged: Professor E Bromhead, Dr D Brook OBE, Professor D Brunsden OBE, Dr M Chandler, Dr A R Clark, Dr J Doornkamp, Professor J N Hutchinson, Dr E M Lee, Dr B Marker OBE and Dr R Moore. The assistance of Halcrow with the preparation of this publication is gratefully acknowledged.
Photo credits Elaine David Studio: 40; High-Point Rendel: 48; IW Centre for the Coastal Environment: 14 top, 19, 20 top, 23, 31 bottom, 41, 42, 47, 50, 51, 55, 56, 62, 67; Dr R McInnes: 14 bottom, 16, 17, 37; Wight Light Gallery, Ventnor: covers and title pages, 4, 6, 16/17 (background), 30, 31, 32, 43.
Copyright © Centre for the Coastal Environment, Isle of Wight Council, August 2007.
Isle of Wight Council publication reference: CCN/ENV58
This guide is intended to provide practical assistance to its readers and information contained within the guide may be reproduced with the permission of the Isle of Wight Centre for the Coastal Environment, Salisbury Gardens, Dudley Road, Ventnor, Isle of Wight, PO38 1EJ, United Kingdom; telephone 0044 (0)1983 857220.
Further details can be obtained at www.coastalwight.gov.uk
Cover photo - 'Ventnor from the sea'. Courtesy Wight Light Gallery, Ventnor managing ground instablity part 1.qxp 13/08/2007 10:39 Page 3
Table of Contents
Executive Summary 5
Chapter 1
Why is there a ground movement problem in the Isle of Wight Undercliff? 7
Chapter 2
What is the scale of the instability problem? 15
Chapter 3
Investigating and assessing ground movement 21
Chapter 4
How can ground instability problems be managed? 33
Chapter 5
Climate change and future management 57
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