Traditionally, sandbags have been used to block doorways, drains and other openings into properties as well as to weigh-down manhole covers, garden furniture and to block sink, toilet and bath drains to prevent water backing up.
However, sandbags are relatively ineffective when compared to purpose-designed flood protection products.
Some of the pitfalls are:
As a result, we strongly encourage people to use purpose made flood protection products, such as flood boards, non-return valves for plumbing and air brick covers.
Don’t assume that the authorities will provide you with sandbags in a flood emergency!
It is the responsibility of property owners to take appropriate action to protect their property from flooding.
Your local council may have some sandbags ready to deploy at times of flooding, but their priority is to protect the public at large. You should check with your own local authority in advance to find out what their policy is and how you can get access to sandbags before flooding starts. There may be a charge for this service.
Remember, during a flood crisis there may be limited stocks per person or supply routes may get blocked.
If your local authority doesn’t supply sandbags, you can buy unfilled sandbags and a supply of sand from most DIY stores and Builders Merchants, but remember that if there is a flood expected in your area demand may exceed supply as people rush to buy them.
In an emergency you can use alternatives such as pillow cases or refuse sacks and fill them with garden soil.
Filling sandbags and building a wall is a physically demanding activity so it is important that all those involved are fit enough to carry out the work.
Remember that they can get heavy quickly, so do not overfill, or fill them too far away from where you want to position them.
A tall sandbag wall must be designed by engineers to withstand the water pressures, as failure or collapse of the structure could pose a danger to anyone nearby.
It is essential the everyone involved in building a sandbag wall is equipped with appropriate personal protective equipment, including gloves and steel toecap footwear. If the sand is dry, eye protection in the form of safety glasses is also required.
If emptied and dried the sacks can be filled again, otherwise they will rot after a period of time if damp. If sandbags are contaminated by flood water, advice should be sought from your local authority environmental health department regarding their safe disposal.
Sandbags are of no use if your property is already flooded – concentrate your efforts on protecting yourself, your belongings and moving precious items out of harms way!
Consider all entry points that water could get through, not just doorways, such as – airbricks, utility service points, cable entry points. Use other solutions for entry points where sandbags won’t work (such as silicone sealant).
You’ll need at least 6 sandbags to keep out 20cm depth of water for a standard door opening. Each sandbag will need approximately 15kg of sand. You should use sharp, not soft, sand.
Building a sandbag wall up to 60cm high by 1 metre in length requires approximately 80 filled sandbags.
If you need to create sandbag protection that is more than three layers high you will need to build in a pyramid style. For the structure to be stable, you should build the ‘sandbag wall’ three times as wide as you need it to be high. Again use the alternative Header and Stretcher method for alternative layers. Compact each bag into place and tuck the loose end firmly under the filled portion of the bag (Figure 5).
Lay plastic sheeting across the side of the sandbag wall on the water side. Weigh down with additional sandbags (Figure 6).
Sandbags are popular but they have disadvantages:
More information on protecting yourself from flooding can be found on the Environment Agency website:
In certain circumstances, local authority grants may also be made available to cover some of the costs of providing resistance and resilience products for individual private dwellings. Contact your local authority to find out whether you may be eligible.
© 2015 The Flood Defence & Recovery Company