The Flood Hub

Click here to read the full article from Aviva: 7th June 2024

… but residents are unaware of flood risks.

• One in nine (11%) have already replaced lawn with fake grass and 10% plan to do so.
• One in seven (14%) have replaced part or all of their garden with a driveway made of non-permeable material.
• Bucking the trend, one in nine (11%) have changed their garden into a wildflower meadow.
• Just under half of UK residents (44%) believe artificial grass has no impact on flood risk.
• Yet 45% of UK residents believe their home is at risk from flooding.

A fifth (21%) of UK homeowners have already replaced or plan to switch their natural lawn with artificial grass, and a further 19% would consider making the swap, according to research by the UK’s leading insurer, Aviva.

The survey, among 2,004 UK homeowners, also found that over a quarter (27%) have already changed or plan to replace part or all of their garden into a driveway with non-permeable material, such as tarmac. A further 21% would consider making the change.

Worryingly, the research shows a slight increase in these changes, compared to the previous year when 18% had already or planned to switch to artificial grass and a quarter (25%) had changed their garden into a non-permeable driveway. Despite this, a related survey found that nearly half of UK residents (45%)2 believe their home is at risk from flooding.

Jason Storah, CEO UK & Ireland General Insurance at Aviva, said: “At this time of year, many of us are thinking about making changes to our homes and outside spaces. Whilst it can be tempting to replace a garden with low maintenance driveways or artificial grass, these changes can make it more difficult for water to be absorbed. At times of heavy rain in urban areas, drains can rapidly become overwhelmed if the water cannot be absorbed, causing flooding outside and in the home.

“As our climate changes, periods of extreme weather are likely to increase, including heavy downpours and higher temperatures. Our flood mapping technology shows that surface water flooding is on the increase and it can be harder to predict, so it’s important to be prepared.”

It seems convenience and low maintenance options are important factors for those making changes. Asked why they had made the change to artificial grass, a third (34%) said they didn’t want the upkeep of a natural lawn or garden. Of those who had already changed their garden into a driveway with non-permeable materials, nearly half (46%) said they needed to make room for another car.

However, some residents are bucking the trend and making changes that may have a positive impact on climate resilience. One in nine (11%) have changed their garden into a wildflower meadow and 13% plan to do so in the future. And almost a fifth (19%) have already or plan to switch their driveway to a garden with plants and flowers.

The research also reveals an apparent lack of awareness of the factors that can impact the chance of a flood occurring. Whilst a third (32%) of UK residents believe artificial grass can increase the risk of flooding, over two fifths (44%) of residents believe it has no impact and 9% think it can actually help to reduce the risk.

Similar confusion exists for driveways built from non-permeable materials. Although over a third (34%) believe this can increase flood risk, one in ten (10%) think it can lessen the chance of a flood occurring.

Storah added: “Even the smallest of planted or permeable spaces can help make a difference. Climate-ready gardens can play an important role in helping to mitigate the impact of heavy rain and reduce the chance of a flood from happening at home.

“Plants, lawns and flowers can not only help to absorb excess water, they can also bring other climate benefits, including improving biodiversity. Equally, plants in the right location can help to absorb heat during heatwaves or droughts. But it’s important to get ready for the future by locating the right plants in the right places. Some shrubs and trees can have extensive root systems which may cause some soil types to shrink in periods of hot weather.

“The materials we use in our outside space can impact the likelihood of our homes being flooded or affected by other climate events. We’d urge residents to ensure their homes, gardens and driveways are climate-ready and resilient to the impacts of extreme weather.”

Aviva has put together advice for homeowners and residents who are considering making changes to their outside spaces:

To help reduce flood risk

Choose more permeable materials such as gravel or block paving. Using permeable materials – that allow rainwater to soak through to the soil below – can help reduce the risk from surface water flooding.

Check if you need planning permission – you may need planning permission if you to intend to change an area of more than five square metres using non-permeable material, such as tarmac, asphalt or concrete paving.

Consider making partial changes – having a border around your drive or installing a drain will help rainwater to run off during heavy downpours, reducing the flow of water into street drains, and may help stop water from entering your home. Or consider using more permeable materials in part of your garden to help with drainage.

Include a wildflower or natural area in your garden – window boxes or the smallest area of wildflowers or more natural planting can attract wildlife and help improve biodiversity in your outside space.

Collect rainwater – consider installing a water butt or other rainwater collection device to prevent water from overwhelming drains. Plants and wildlife prefer rainwater to tap water too and during droughts, rainwater collection devices can help to save water.

Check your home’s flood risk – even if your home is nowhere near a river or the sea, it could still be at risk from flooding, so check your home’s status with the Environment Agency.

Climate-ready planting

• Don’t plant trees or large shrubs close to your buildings. Most people will think about their home, but the same applies to garages and outbuildings. Also remember, that a cluster of smaller, individual hedge plants can have a greater impact when grouped together. A suitable distance will depend on the type of subsoil, variety of tree and depth of foundations, so if in any doubt, check with an expert.
• Choose your tree variety wisely. Information published by the ABI (Association of British Insurers) suggests that certain types of trees – including poplar, willow, elm and oak – are more likely to cause problems than others, due to their long, fine root structures. According to the National House Building Council, lower water demand trees include birch, elder, hazel and magnolia. Residents may wish to consult an arborist for expert advice, if they are unsure about which varieties to plant.
• Consider whether shrubs could be moved if they are too close to your property. If a shrub was planted after the home was built and is still relatively small, it may be possible to reposition them elsewhere.
• Keep a close eye on trees close to your property or garden. If a tree is in the street or on a neighbouring property, it’s still possible to affect your home or outbuildings if positioned close to your structures, so be mindful of any signs of shifting or cracking.
• Be particularly vigilant if clay soils are common in your region. Subsidence is more likely to occur in areas where clay soils are prevalent because they are more prone to shrinking during hot weather. Clay soils are more common in southern England, so residents here are warned to be on their guard.

Aviva’s Building Future Communities reports have highlighted the risks faced by changing weather patterns. More information and advice on extreme weather can be found at Building Future Communities report 2023 – Aviva.