This blog been written by a member of the Newground Flood Team.
What is Property Flood Resilience?
Property Flood Resilience (PFR), sometimes referred to as Property Level Protection (PLP), is the term used to describe the ways to protect properties from flood damage. It involves adapting homes and buildings to withstand flood events, focusing on resistance (keeping water out) and resilience (recovering quickly post-flood).
Property flood resilience can be integrated into the design of new buildings or retrofit into existing ones. Homeowner and resident consultations are vital part, and it’s important that they fully understand what’s involved in the process and that the end result meets their needs and requirements. A PFR solution must consider many factors in order to be successful.
Understanding Property Flood Resilience
Understanding Property Flood Resilience (PFR) is crucial for users looking to manage flood risk effectively. Buildings can have multiple water entry points, such as such as seeping up through the floor, penetrating the foundations into the sub-floor and livings areas, permeating wall cavities, infiltrating porous building materials, breaching party walls, overwhelming drainage systems, and entering through building apertures like doorways, windows, vents, airbricks, weepholes, and cable and pipework entry points. Identifying routes of ingress, giving to consideration to the properties flood risk, construction type, and the lifestyle of the resident, are all key to determining the most appropriate strategy and options design package.
With so many routes of water ingress often present, product limitations and the depth and duration of a flood event means that even after a PFR strategy has been implemented, minor seepage may still sometimes occur. For example, flood products such as flood doors and barriers have an allowable seepage rate when under test conditions for kitemarking which end users should be aware of, with the understanding that PFR aims to manage risk whilst finding the right balance between protection and practicality. While allowable seepage from a flood door is relatively minor (easily absorbed by a towel), those unaware of the fact may think that the door has fault, when in fact it’s done its job perfectly in keeping the floodwater at bay.
Resistance. Things to consider…
A resistance strategy focuses on preventing and ‘resisting’ water entry through the structure and fabric of a building. Common resistance measures include flood doors, barriers, SMART airbricks, sealants, and non-return valves (NRVs). This approach offers a relatively quick and more affordable solution with minimal disruption to the home. However, its suitability depends on factors such as flood risk, building design, and resident circumstances. Properly implementing a resistance strategy requires expertise in understanding how building materials react when in contact with floodwater and the ability to predict how water will enter the property.
Resistance products can be categorised into active and passive options. Active products require manual installation when a flood is expected e.g., flood barriers and airbrick covers, whereas passive products remain permanently in place and offer flood protection 24/7 without the need for any manual intervention. Passive solutions, like flood doors and self-activating SMART airbricks, offer convenience but may be more expensive.
Considerations for keeping water out of a building extend to include the pressure exerted on external walls by floodwater. The force increases with water depth and flow rate, meaning consideration must be given to the height to which a property can be safely protected without risking structural damage. While guidelines suggest a safe height of 600mm (2ft), many properties in flood-prone areas are protected up to 900mm (3ft). Structural surveys may be needed beyond 600mm, and exceeding a property’s safe height for resisting water pressure can risk structural damage. Beyond this point, it may be advised to allow floodwater to overtop barriers and enter a property to prevent potentially catastrophic structural damage. The force applied to external walls by flood water means that even a relatively light impact from floating objects and debris, such as vehicles and tree limbs, can be enough to cause a wall to buckle and collapse, posing risk to life.
Furthermore, resistance strategies may not be suitable for all properties, particularly those with timber frames or more traditional design. Listed buildings and those located within conservation areas may also bring further considerations, and engagement with conservation officers is advisable to ensure compliance and the preservation of architectural appearance and integrity.
Resilience. Things to consider…
A resilience strategy focuses on enhancing a flooded property’s recoverability by minimising damage to both its external and internal structure, surfaces and living spaces. When implemented effectively, resilience measures can significantly reduce the impact of flooding, meaning a quicker recovery and reoccupation of the property. This can potentially eliminate the need for insurance claims and alternative accommodation and ease the stress and burden on homeowners and residents.
Materials such as water-resistant wallboards, hardwoods, plastic skirting boards, and ceramic wood-effect floor tiles are resilient to flooding and can be cleaned, disinfected, and retained in place. Installing sump and pump systems, stainless steel kitchen units, and elevating plug sockets, utility meters, and appliances are also effective resilience practices. These adaptations ensure that if floodwater enters the home, the likelihood of it damaging electric appliances and equipment is reduced, surfaces can be easily cleaned, and the home made habitable again within days rather than months.
Implementing a comprehensive resilience approach can be significantly more costly and disruptive compared to a resistance strategy. However, the post-flood reinstatement phase presents an advantageous opportunity to integrate water resilient materials and design principles – a concept known as “build back better”. Despite the long-term benefits, the insurance industry has been hesitant to embrace flood-resilient repairs. Consequently, homeowners pursuing a resilience approach may need to negotiate agreeable settlement figures with their insurers and oversee the work themselves.
While investing in a water-resilient building can pay dividends over time, homeowners choosing to project manage the work themselves may find that it could extend the amount of time they are out of their home; potentially adding additional stress and strain on family and finances. Nevertheless, the long-term benefits of resilience measures often outweigh the initial challenges, making them a worthwhile investment for flood-prone properties.
Resistance, Resilience, or both?
While keeping spend relative and proportionate to the level of flood risk, each property and set of circumstances are unique. A holistic view best serves to cover all bases and the optimal strategy to take when protecting a property can only be derived from the consideration and assessment of a range of different factors.
Pump Systems
In addition to mitigating the risk of groundwater flooding in basements and cellars, or water seeping up through the ground floor, pump systems play a crucial role in preventing rising water levels within a property. They can act as a backup in case a resistance product fails or if water enters through new or unidentified routes. Providing the pump can remove the water at a quicker rate than which enters, damage to the building, furniture and possessions can be avoided.
A standalone puddle sucker pump is a valuable addition to any resistance or resilience package, offering a solution for any minor, unexpected water ingress. While manual operation is required for these pumps, a passive alternative exists in the form of a sump and pump system. This system involves installing a pump within a sump pit / chamber in a basement or cellar, or the sub-floor area or ground floor of a property, with the pump connected to the mains power supply. Float switches attached to the pump activate it automatically, discharging water through an outlet pipe without any homeowner intervention.
To address potential power outages, pumps can be powered by battery backup systems or even petrol or diesel generators where safe to do so. Generators should be operated outside or in well-ventilated areas or outbuildings to ensure safety. Having backup power sources ensures continuous operation of pump systems, enhancing the overall flood resilience of the property.
Sump and Pump System
Pumps systems should be suitably spec’d according to requirements, and professional advice and installation is recommended. You can find more information about sump and pump systems by clicking here.
The Property’s Flood Risk
Assessing a property’s flood risk as part of the PFR journey is a crucial starting point. This assessment provides insights into various sources of flood risk and the likelihood, potential depths, and durations of flood events – all crucial elements for consideration during the survey and options design stages. Neglecting this assessment when implementing PFR could leave homes vulnerable to more significant events or other sources of flood risk.
Flooding
It’s essential to identify ALL potential sources of flood risk, including river and coastal flooding, surface water, sewer and groundwater flooding, as well as risks posed by canals, ordinary watercourses and natural drainage systems, such as brooks, streams and dykes.
To find out more about flood risk in our ‘Understanding Flood Risk’ blog, by clicking here.
The Property and its Location
When evaluating flood risk, various factors about the property and its surroundings must be considered. This includes the type, age, construction, condition, and contents of the property. Semi-detached or terraced properties may also be susceptible to flooding from neighbouring properties either via the sub floor area or via seepage through party walls, highlighting the importance of understanding permeability and water entry points.
For listed buildings or properties in conservation areas, restrictions may apply to flood protection products and measures. Consulting local authorities, planning departments, and conservation officers to discuss permissible measures and works is advised. To download our booklet on PFR in traditional vs modern properties, click here.
A property’s flood risk assessment guides the focus of the Property Flood Resilience (PFR) survey. This survey evaluates the property’s existing level of resilience and other property specific elements including the building fabric, design type, age, water entry points, local topography, elevation, and onsite drainage. Recommendations aim to mitigate the impact of flooding while adhering to building restrictions, ground conditions and flood onset times.
The Residents and their Circumstances
The ability of residents and their availability to respond promptly to flooding are important considerations. Automatic flood protection products may be preferable for homeowners regularly away from the property or unable to leave work. Additionally, factors such as age, health, and mobility influence residents’ capacity to install flood defences and manage post-flood recovery.
Budget constraints may also play a significant role in determining the feasibility of PFR options. Where communities have been significantly affected by a large-scale flood event, the UK government may provide property flood resilience grant schemes via local authorities, allowing eligible homeowners to claim up to £5,000 worth of funding to reduce the impact of future floods. Insurance initiatives (such as Flood RE’s Build Back Better scheme) can also provide financial support to eligible homeowners. Find out more about the Build Back Better scheme by clicking here.
Maintenance
Proper maintenance of flood resilience equipment is often overlooked but it is essential for effective flood protection. Regular maintenance prevents equipment failures and ensures functionality during flood events. Over time, rubber seals will perish, and extremes of hot and cold weather can lead to the expansion, contraction, hardening and cracking of plastics, sealants and other materials exposed to the elements. Products such as flood doors and windows are often accompanied by guarantees which remain dependent on product servicing at specified intervals, usually by either the manufacturer or supplier for an additional cost or service charge. Therefore, it’s important to factor in these ongoing annual maintenance costs when implementing PFR.
Download out PRF Health Check resource here.
Kitemarking
The kitemark standard for flood protection products is BS 851188, which replaced the previous publicly available specification standard PAS 1188. Kitemarked products undergo independent testing by the British Standards Institute (BSI), where they are subjected to specific flood conditions such as static water, currents, and waves. This rigorous testing process helps instil confidence in the quality and effectiveness of these products during flood events.
Find out more information about the BS 85118 Kitemark by clicking here.
The Property Flood Resilience (PFR) Code of Practice
The Property Flood Resilience Industry Code of Practice (CoP) was released in February 2020 and developed by CIRIA (Construction Industry Research and Information Association) and BRE (Building Research Establishment). The CoP provides the guidance and industry standards for the delivery and procurement of Property Flood Resilience and is designed to give confidence to property owners in obtaining professional advice, quality products, installation and maintenance of property flood resilience measures, property adaptation and good practice.
The Code of Practice sets the standards across the six stages of PFR delivery:
The PFR Code of Practice has been developed in consultation with the DEFRA PFR roundtable and professional bodies including CIWEM, ICE and RICS, and will result in development and delivery of accredited training for industry professionals across all six stages of PFR delivery.
More information on the PFR Code of Practice can be found here.
Flood Performance Certificate
With less than one in three property owners researching flood risk before purchasing, and nearly two-thirds having never checked their flood risk at all, the Association of British Insurers (ABI) has proposed changes to address this gap. Under these proposals, homeowners in flood risk areas would need to include a property flood resilience survey as part of the selling process. Central to these proposals is the introduction of a Property Flood Resilience Database (PFR-d), along with a traffic light system and scoring model similar to the Energy Performance Certification Scheme. The mandatory PFR survey and accompanying report would provide potential buyers with crucial information about a property’s flood risk, its current level of resilience against flooding, and recommended measures to improve its flood resilience score.
Proposed property flood resilience database.
Implications on Insurance
While Flood Re currently enables affordable flood insurance cover for many homeowners, the scheme will only remain in place until 2039. Going forward, pricing will no longer be capped, and domestic flood risk policies will revert to a free market. With PFR scores collated on an insurance industry-accessible database, it would allow a property’s level of flood resilience to be more accurately reflected in its insurance premiums. Simply put, the higher the PFR score, the lower the cost of flood insurance.
Additionally, as part of Flood Re, the ‘Build Back Better’ initiative allows insurers to provide an additional sum of up to £10,000 on top of a flood damage claim for the implementation of property flood resilience measures.
You can find out more about Flood Re, by downloading our resource here.
You can find more information about the Flood Re ‘Build Back Better’ initiative here.
Why is this important in a resilience strategy?
Water-resilient design, construction and materials hold significant appeal to insurers. Unlike a resistance approach, which relies on human and technological interventions, resilience strategies eliminate these factors, reducing the risk of human error and product failure. Based on the principle that if it can’t be damaged it won’t need repair, resilience measures offer the best chance of damage reduction if floodwater enters a property. If flood performance certificates are implemented in the future, resilience measures would likely score higher than resistance measures in any PFR scoring process.
For more information on property flood resilience, you can find The Flood Hub’s Property Flood Resilience Toolkit Free Download by clicking here.
