Coping with floods: beyond the sandbag

Thousands of Brits have just had a rude awakening to the dangers of flooding. But it’s time to look beyond sandbags, argues Steve Hodgson, chief executive of the Property Care, the UK trade body for structural waterproofing, wood preservation, damp proofing, flood recovery, structural maintenance and invasive weed control

The idea of protecting your own home from encroaching flood water is nothing new. After all, it’s in our very nature to want to protect our family, our belongings, our investment and our home.

The panic so evident in those feverishly working to fill and distribute sandbags at the moment stands testament to that.

But the truth is that sandbags alone are little better than useless – they have become the nation’s flood placebo.

They are cheap, visible and make us feel better but, on their own, actually do nothing to stop water. To be clear, they simply don’t work on their own.

Hessian bags filled with sand are not waterproof! Plastic bags filled with sand cannot form a barrier that doesn’t have holes between the bags. Unless sand bag walls are properly ‘built’ sufficiently thick and made of the right materials they are almost useless. All sand bags can do is slow the encroaching water - a little.

If they are properly placed they can slow water down to a point where pumps can be used to evacuate the water in the area behind them. This is useful when reinforcing river banks, redirecting flowing water or repairing civil defences. They don’t often prove effective in helping individuals who are trying to keep encroaching river water out of the front door!

Why are they used? Because they give people something to do at a time when they feel that they need something to do. But how many houses have you seen that have been protected by a few sandbags placed at the threshold?

The term ‘property level flood defence’ first came into common use shortly after the catastrophic floods of 2007. The government and insurance world realised they would never protect every home at risk of flooding with civil projects, so began to look at the possibility of encouraging homeowners to protect themselves.

Industry was, as ever, one step ahead and the market for flood protection products resulted in a great deal of innovation and a good measure of ingenuity.

A range of products, technologies and techniques has since been developed that can make some homes almost completely flood-proof.

The idea that we can keep occupied spaces dry even in very wet conditions is also nothing new. If we’re able to waterproof basements deep below street level, it must be possible to keep rooms that only get wet very occasionally free of water and that is indeed the situation.

At a basic level, demountable floodgates - barriers that can be fixed in place make door openings waterproof - and air brick covers that can stop water getting in through the sub floor air vents can prevent water coming in through doorways and openings, while non-return valves can be placed in drains and sewers to prevent foul water discharge.

These measures can slow the passage of water but seldom stop it completely. They can buy time and sometimes that’s enough.

In a number of vulnerable locations, pumps have been placed below timber floors. They sit dormant when it’s dry, but can spring to life during a flood. This intervention can alleviate problems in some circumstances but when combined with floodgates, valves and vent covers they can start to produce a house that is getting pretty flood-proof.

In some situations, often where someone has been flooded several times, floor protection measures can be taken further. Clear waterproof coatings that can withstand considerable water pressure can be painted on to outside wall surfaces. Flood-proof doors and garden walls or other features designed to act as a flood barrier, together with other permanent and demountable barriers, can also keep water at bay.

Impervious coatings, often referred to as ‘tanking’, can be applied internally to solid floor and walls and it’s sometimes possible to install internal water management systems incorporating channels, membranes sumps and pumps. These can be designed to direct any water that does get in through the walls and floors back out before it can affect the living space.

Any of the measures outlined above can and will affect the ability of a house to repel flood water but, as with most things, the more spent, the more gained. It’s possible to do a lot with a little but, it is hugely important that these measures are properly considered, thoughtfully designed and professionally installed.

Property level flood defence is something anyone in an area at risk of flooding should consider. It can be inexpensive, practical and very successful if done right.

It also means that when the next flood comes you can help fill sandbags for your neighbour, safe in the knowledge that your home, family and possessions are as well protected as they can be.