The Bigger Picture

How can we minimise damage to buildings from flooding?

The very real cost of floods

Flooding events such as those in Winter 2015/16, have challenged all aspects of industry.

The Environment Agency (EA) produced a summary report[1] that gave an estimate for the costs of Storm Desmond and Storm Eva, as around £1.6 billion to UK industry. Floods cause significant disruption, inconvenience and expense and it’s difficult to predict where and when they will occur.

New homes built in flood plains

With up to 275,000 more homes needed every year[2] to meet the demand, we are requiring more houses to be built. As many of us maintain the desire to be connected to urban areas, we often see that many of these new sites are located around areas of existing development. This may mean that some of the sites chosen are ones that may not have been selected during the construction of initial building. In the case of flooding, this may mean that new homes could be being constructed in areas that may be at a risk of flooding.

With the additional pressures of climate change, this risk will be exacerbated further in future. Ideally homes would not be built in flood plains but the reality is they are. However, just because a flood risk is present to a site, does not mean that there is nothing we can do to limit the damage to properties. By making simple design changes to traditional construction, there are several things that can be done to new and existing homes so that if a flood was to occur, this damage would be significantly limited. These changes will have significant benefit to the home owners for decades to come.

Protecting properties from floods

A manual resistance barrier installed on a community centre in Cumbria.

Property flood resilience (PFR) measures are aspects that can be installed on a property to do just that. Adapting homes to floods can come in two different forms.

Firstly, resistance measures. This type of measure limits the ability for water to enter a building. Commonly, this includes the use of aperture barriers such as window or door barriers as seen in the picture (right). Some of these measures require an individual to install them so they are known as manual measures. Alternative measures may prevent water from entering a building just through normal practice e.g. the closing of a front door so these are called passive measures.

As well as resistance measures, we also can see recoverable (or resilience) measures which are designed for situations where keeping the water out may not be the best approach. These will limit the damage done internally to a building and will help to allow building occupants to return as quickly as possible. This could include

A tiled floor can be sealed into waterproof walls to provide a recoverable internal floor finish.

ensuring that wall finish and flooring utilise internal waterproof characteristics, such as tiled flooring, or

by wiring buildings so that electrics flow down from the ceiling instead of up from floor levels and

placing outlet sockets well above the expected threshold of flooding.

Government and industry co-operation on flooding

The UK Government’s 25 Year Environment Plan[3] has committed to supporting an industry-owned Code of Practice for PFR, due for release in 2019. This will help to provide accessible guidance for the use of these technologies in practice. This will help to promote consumer and business confidence in PFR and reduce the impact of future flooding events on the UK.

Raising awareness of PFR and how this works in practice is an additional key challenge for industry. The Defra Property Flood Resilience Roundtable published their impartial findings in the Property Flood Resilience Action Plan[4] in September 2016. The plan seeks to identify appropriate work streams to address key industry challenges. In order to raise awareness, the Roundtable has created an impartial information site called FloodGuidance.co.uk.

The roundtable is working with industry to raise the awareness of what flood resilience can really look like and is talking to stakeholders to help promote best practice during construction.

Reducing the damage from floods and climate change

Measures to stop flood water entering properties and reducing the harm flood waters do in flood prone areas are vital. The industry is working hard to increase awareness and guidance on property flood resilience measures but there is a lot more to do. Greater adaptation will ensure less damage and costs are incurred by floods, something that is increasing important due to climate change.

Matthew Barker is the technical lead for flooding at the BRE’s Centre for Resilience. To check if your home or business is at risk of flooding read more here.

[1] Environment Agency (2018) Estimating the economic costs of the 2015 to 2016 winter floods

[2] Department for Communities and local government (2017) Fixing our broken housing market

[3] HM Government (2018) A Green Future: Our 25 Year Plan to Improve the Environment

[4] Department for Environment Food and Rural Affairs (2016) The Property Flood Resilience Action Plan

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