How do sandbags prevent flooding?

As winter approaches and the warmer weather of the summer disappears, thoughts are beginning to turn to bad weather, and the best methods of flood prevention and risk management.

In this article we outline the benefits of sandbags, how sandbags work when looking at combatting flooding, and a number of alternative products that can be used instead of sandbags, or in addition to traditional sandbags.

If you have any questions or queries about the best methods of flood prevention and any of our flood defence products, don’t hesitate to get in touch with our team of experts – call our team on 01752 692221

How do sandbags work?

Sandbags are a great method of holding back floodwater, and have been in use for hundreds of years. Sandbags are a simple, low cost and effective method of preventing damage caused by flooding and floodwater, whether it is damage to properties and contents within the property, or damage to the floor surface, vehicles and more.

But how do sandbags stop water from passing through and into the protected area?

Sand is a coarse, non-porous material, meaning water cannot pass through it. When water approaches the sandbag, any mud, silt and other materials within the floodwater fills the gaps between sand particles, creating an increasingly robust barrier that prevents water from passing through.

Sand has a hydrophilic property, meaning that when sand is wet, a layer of water will form on the surface of the sand granule. When wet sand is packed tightly together, the water layers on each sand granule will interact with the surrounded water layers, creating bonds between them. This is the science behind sandbags – when sand gets wet, its performance as a flood barrier increases.

Additionally, as sandbags get wet, their weight increases. When a barrier of sandbags has been created, and the floodwater approaches, they will become increasingly heavy, and the weight of the sandbags will cause the sand to become more tightly packed together, compressing the sand particles together, further minimising the number of gaps that the water could potentially pass through.

What to use instead of sandbags

With advances in technology and manufacturing processes, a number of new innovative products have been created as alternatives to traditional sandbags. Here at Drainage Superstore we have a number of alternative products that can be used in conjunction with or alongside traditional sandbags to prevent flooding.

Alternatives to sandbags:

1. Hydrosack
2. Floodstop
3. Door flood barriers
4. Airbrick flood defence

1. Hydrosack

Hydrosack is a modern and effective alternative to a traditional sandbag. The Hydrosack is manufactured from a non-woven outer material, combined with a super absorbent core, weighing a total of less than 0.5kg. When the water comes into contact with the Hydrosack, the core absorbs up to 20 litres of water and expands, acting as a sturdy form of flood defence, preventing flood water from passing through, and redirecting it as required.

The Hydrosack comes with handles to improve ease of movement and adjustment as required. Additionally, the Hydrosack is a great alternative to traditional sandbags as they do not require filling, they are lightweight and compact when not in use, and are safe and easy to dispose of – after use the contents can be dispersed into the ground, or sent for landfill or incineration.

2. Floodstop

Floodstop is another alternative to sandbags, designed to divert floodwater away from properties and areas that can be damaged by excess water.

Floodstop is a modular barrier, made up of a number of different sections that can be pieced together using weighted universal keys, to form a barrier of the length required. The barrier can be assembled to any length, in any direction and with any form of opening, providing maximum flexibility and installation potential.

3. Door flood barriers

If a building is situated in an area such as a floodplain, where there is a high risk of flooding, a door barrier might be more suitable. A door flood barrier is an easily installed barrier that sits in front of an external door, and can be removed and stored away when not in use. The installation of the flood barriers is relatively unobtrusive, and the fixings are barely noticeable when the barrier is stored away and not in use.

There are heavy duty barriers available for commercial buildings and wide apertures, as well as smaller barriers for domestic properties.

4. Airbrick flood defence

Airbrick flood defence products have been designed to help minimise the risk of properties flooding. Airbricks in domestic properties are one of the first points of entry of floodwater into a property, as they are generally either situated at the floor or below floor level.

The Airbrick flood defence from Manthorpe consists of a frame, which is installed around the airbrick, and a bright yellow cover that is clipped onto the frame when required to prevent water from entering the property through the airbrick. The cover is bright yellow so that it is noticeable when the floodwater subisdes, reminding the property owner that the cover can be removed.

Got any unanswered questions about sandbags and other flood defence alternatives? Our team of experts are ready to help, just call on 01752 692 221 or use the live chat in the bottom right hand corner.

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