In 2024, Nick Lupton’s home became a viral sensation across British media. Sitting on the floodplain of the River Severn, it had faced multiple flooding incidents over the years. But this time was different, they were prepared. A newly built flood wall kept the rising waters at bay, capturing the attention of the public. With flood risks increasing, homeowners and business owners are looking for solutions to protect their properties with robust measures. However, a flood wall isn’t just about laying bricks and hoping for the best. If it’s not done properly, it could collapse, exacerbate flooding, or make flooding worse for others.
I recently visited a homeowner we worked with to assess their flood risk and guide them through the process of obtaining the necessary consents. The flood wall is now in place, and it’s a great example of how to do things the right way.
The Problem: Flooding Through the Property Wall
When we first visited said property, there was just a small box hedge where the new wall now stands. During heavy rain, the Main Street would flood, and water would flood into the property through the property wall and other apertures. Being an older structure, it was extremely porous, allowing floodwater to flow straight through.
A flood wall was considered, and the council were agreeable with the idea. As with any flood protection measure, it had to be properly designed and built to ensure it would be effective, and crucially, that it wouldn’t displace water and make the problem worse elsewhere.
The Solution: A Properly Designed Flood Wall
The wall that now stands in place is a double-skin wall with an F2-rated brick, designed specifically for exposure to wet conditions.
It features:
✅ A 50mm concrete cavity reinforced with steel rods that tie into the foundation for strength.
✅ Stainless steel ties between each skin of bricks to ensure structural integrity.
✅ SBR additive in the concrete and mortar to improve waterproofing.
This method provides more strength than a simple double-skin brick wall, whilst displacing minimal water, key considerations in flood protection.
The Right Process for Building a Flood Wall
If you’re considering a flood wall, here’s the step-by-step process you must follow:
- Flood Risk Assessment – The first step is understanding the type of flooding that may impact the property, along with the depths, onset time and duration, coupled what solutions may be viable.
- CCTV Drainage Survey – This ensures you know exactly where drains are located. A flood wall is clearly only defending against above ground flows, however if drainage routes cannot be defended against beneath ground, the defended area could quickly fill with water, being bypassed. It is not always viable to isolate the drainage at a boundary, and therefore knowing the drainage routing is vital.
- Options Development – Assessing where the wall will go, ensuring minimal water displacement so you don’t impact neighbouring properties.
- Floodplain Impact Calculations – If the wall is going to displace water, compensatory storage may be required, such as lowering an area of garden to offset the loss of floodplain storage. The nearer the wall is to the property, the less volume that is likely to be displaced.
- Structural Design – The wall needs to be strong enough to resist overturning and sliding. I’ve seen garden walls pushed over by floodwater simply because they weren’t designed and built to withstand flooding. If the wall was to suddenly collapse, the mechanism of failure is much more significant than if the flood water had gradually risen in its natural state. The wall failure could cause a significant wave of water, resulting in further collapse, or worse, even injury or death.
- Consents & Permissions – Depending on your location, you’ll may need approval from local authorities or environmental agencies before construction can begin. Check out our other blog here which details the different consents needed: https://fpsenvironmental.co.uk/building-a-wall-as-a-flood-defence/
- Construction – Only after all the above steps are completed should a spade go into the ground!
Why You Can’t Skip These Steps
Too often, I see people jump straight to building a flood wall without considering where drains flow or whether the wall will withstand pressure from floodwaters. In the worst cases, this results in ineffective walls that create more problems than they solve, either by allowing water to pool behind them or collapsing under the pressure.
At FPS Environmental, we are able to provide homeowners and business owners through the various stages, ensuring that their flood protection is effective, robust, and compliant with regulations.
If you’re considering a flood wall and need expert guidance, get in touch with us today.
Should you wish to read up on Nick Lupton’s wall, you can read his PDF guide here.
Written by: Simon Crowther BEng (Hons) C.WEM FCIWEM