Flooding and Historic Buildings in Wales July 2019 TECHNICAL Statement of Purpose Flooding and Historic Buildings in Wales provides For information on specific historic buildings and guidance on ways to establish flood risk and prepare guidance on whether remedial treatments and repairs for possible flooding by installing protection measures. require consent, you should consult the conservation It also recommends actions to be taken during and officer in the local planning authority. after a flood to minimise damage and risks. Sources of further information and practical help are Aimed principally at home owners, owners of small listed at the end of the document. businesses and others involved with managing historic buildings, Flooding and Historic Buildings in Wales explains how to approach the protection of traditional buildings and avoid inappropriate modern repairs in the event of flood damage. Acknowledgement Cadw is grateful to Historic England for permission the express written permission of both Historic to base the text of this best-practice guidance on England and Cadw. All rights reserved. Historic Flooding and Historic Buildings, published in 2015. England does not accept liability for loss or damage arising from the use of the information contained The original material is ©Historic England 2015. in this work. www.historicengland.org.uk/images- Any reproduction of the original Work requires books/publications/flooding-and-historic-buildings- Historic England’s prior written permission and any 2ednrev reproduction of this adaptation of that Work requires Cadw Welsh Government Plas Carew Unit 5/7 Cefn Coed Parc Nantgarw Cardiff CF15 7QQ Telephone: 03000 256000 Email: [email protected] Website: https://cadw.gov.wales/ First published by Cadw in 2019 Digital ISBN 978-1-83876-805-8 © Crown Copyright, Welsh Government, Cadw, except where specified. WG37562 Cadw is the Welsh Government’s historic environment service, working for an accessible and well-protected historic environment for Wales. Mae’r ddogfen yma hefyd ar gael yn Gymraeg. This document is also available in Welsh. Cover photograph: Storm force seas battering a listed seafront shelter on Marine Terrace, Aberystwyth.© Keith Morris 1 Flooding and Historic Buildings in Wales Contents ¬ Introduction 4 5. After a Flood: Minimising Flood Damage in Old Buildings 20 1. Types of Flooding 6 5.1 Waiting for the Water to Recede 21 1.1 River Flooding 6 5.2 Initial Drying, Decontamination and Cleaning 22 1.2 Coastal Flooding 6 5.2.1 Safety Check 22 1.3 Surface, Groundwater and Sewer 5.2.2 Decontamination and Cleaning 22 Flooding 7 5.3 Assessing and Recording the Damage — Post-flood Survey 22 2. Establishing Flood Risk 8 5.3.1 Structural Issues 23 5.3.2 Reconnecting Services 23 3. Being Prepared for Flooding 10 5.3.3 Drains and Sewers 23 3.1 Availability of Insurance 11 5.3.4 Salvaging Detached and Damaged Items 23 3.2 Protecting Old Buildings from Flooding 11 5.3.5 Security 24 3.2.1 Flood Protection Survey 11 5.4 Drying Out 24 3.2.2 Flood Resistance and Flood Proofing Measures 14 5.4.1 Investigative Work and Opening-up 24 3.2.3 Maintenance and Recording 14 5.4.2 Plan for Drying Out 25 3.2.4 Temporary Flood Barriers 15 5.4.3 Natural Ventilation 26 3.2.5 Permanent Barriers 16 5.4.4 Assisted Drying 27 3.2.6 Flood Resilient Measures 16 5.4.5 Mechanical Ventilation — Using Fans 27 3.2.7 Consents for Flood Resilient and 5.4.6 Background Heating 27 Resistance Measures 17 5.4.7 Dehumidification 27 5.4.8 Monitor the Drying Process 27 4. Dealing with a Flood 18 5.4.9 When has Adequate Drying been 4.1 What to do When Floods are Forecast 18 Achieved? 27 4.2 What to do When your Building is Being 5.5 How Flooding Affects Historic Building Flooded 18 Materials 28 4.3 Returning to the Building 19 5.5.1 Masonry 28 4.4 Notifying Insurers 19 5.5.2 Concrete 29 5.5.3 Earth Construction 29 5.5.4 Structural Timber 29 5.5.5 Timber Panelling and Other Woodwork 29 5.5.6 Render and Plaster 30 5.5.7 Metalwork 30 5.5.8 Ironmongery 30 5.5.9 Wall Coverings 30 2 Flooding and Historic Buildings in Wales 5.5.10 Paint Finishes 31 Further Information 32 5.5.11 Wall Paintings 31 Principal Sources of Flood Advice 32 5.5.12 Re-servicing 31 Other Sources of Advice and Information 32 5.5.13 Personal Possessions 31 Publications 33 5.5.14 Cost and Programme Implications 31 Contacts 34 5.6 Monitoring the Long-term Effects 31 3 Flooding and Historic Buildings in Wales Introduction ¬ The historic environment is a vital part of our shared The Planning (Wales) Act 2015,5 the Well-being cultural heritage. It shapes our sense of place and of Future Generations (Wales) Act 20156 and the identity, and contributes to our well-being and quality Environment (Wales) Act 20167 embed the principles of life. Some elements of the historic environment of sustainable development and emphasise the need have been identified as nationally important — for collaborative working and early engagement. scheduled monuments, listed buildings, conservation Together, these form the background for the areas and registered historic parks and gardens. Welsh Government’s National Strategy for Flood Alongside these nationally recognised assets, there and Coastal Erosion Risk Management,8 which sets are many historic buildings which contribute to local out objectives on flood and coastal erosion risk character, but have no formal recognition or protection management and provides the policy framework yet their survival should be important to us all.1 to help public bodies, communities and other organisations work together to manage flood risk. The risk of flooding is likely to increase as a result of a changing climate and the effects of increased urban Integrated flood risk management is essential if the development.2 Already, around 200,000 properties historic environment is to be protected from flood in Wales are at risk of flooding from rivers and the damage, and effective communication between sea. Thousands more properties are at risk of surface all those involved is therefore vital in securing the water flooding. Many of these buildings will have been appropriate response. Cooperation with national constructed before 1919 and will therefore be of agencies such as Natural Resources Wales9 is key to historic importance.3 managing risks at a local level. The Wales Resilience Forum and local resilience forums also have a very As well as damage to property and infrastructure, important role in helping manage the risks as well as flooding results in a significant human cost. Not only providing integrated emergency management.10 do householders lose possessions and suffer damage to their properties when there is a flood, but often 11 they are also forced to endure the disruption and Conservation Principles stress caused by several months of evacuation. Building conservation is concerned with retaining The need for a more comprehensive management original fabric and cleaning or repairing it in a sensitive of flood risk for people, houses and businesses fashion. Most historic structures are inherently has been addressed in the Flood and Water durable and are relatively resistant to flooding. Management Act 2010 and subsequent regulations.4 Historic timberwork, panelling, floorboards and plasterwork, for example, can often be retained and 1 For more information about the historic environment in Wales, see www.gov.wales/cadw 2 UK Climate Projections (UKCP18) www.metoffice.gov.uk/research/collaboration/ukcp 3 See Historic Environment & Climate Change Sector Adaptation Plan, which helps raise awareness of the risks and opportunities of climate change for the historic environment and the need for adaptation. Historic Environment Group, 2018 4 Flood and Water Management Act 2010 www.legislation.gov.uk/ukpga/2010/29/contents 5 Planning (Wales) Act 2015 www.legislation.gov.uk/anaw/2015/4/contents/enacted 6 Well-being of Future Generations (Wales) Act 2015 www.legislation.gov.uk/anaw/2015/2/contents/enacted 7 Environment (Wales) Act 2016 www.legislation.gov.uk/anaw/2016/3/contents/enacted 8 National Strategy for Flood and Coastal Erosion Risk Management, Welsh Government www.gov.wales/flood-and-coastal-erosion-risk- management-strategy 9 Natural Resources Wales www.naturalresourceswales.gov.uk/flooding/?lang=en 10 Wales Resilience Forum www.walesresilience.gov.uk/?lang=en 11 Cadw’s Conservation Principles sets outs a comprehensive approach to the protection and management of the historic environment, which includes all historic buildings, whether or not they are listed. Conservation Principles for the Sustainable Management of the Historic Environment in Wales, Cadw, Welsh Assembly Government, 2011 www.cadw.gov.wales/advice-support/conservation-principles 4 Flooding and Historic Buildings in Wales conserved after flooding, but all too often they suffer Areas of responsibility from inappropriate remedial works carried out by contractors who have little understanding of historic Welsh Government fabric. The Welsh Government is responsible for developing There have been many cases where sodden materials flood and coastal erosion risk management policy. that appeared at first sight to be too damaged have It funds flood and coastal activities undertaken by been retained in place or reused and repaired in Natural Resources Wales and local authorities. a cost-effective manner. Much damage can also be caused by rapid artificial drying methods that Natural Resources Wales are not correctly controlled. Well-intentioned but Natural Resources Wales provides an oversight of inappropriate techniques for drying out can be very all flood and coastal risk management in Wales. It is damaging to historic building fabric. responsible for managing flooding from main rivers, In some cases, the building and insurance industries’ reservoirs and the sea and provides technical advice standard procedures for making buildings habitable and support.