Sandbag usage
In an emergency, sandbags can be used to block doorways, drains and other openings into properties to keep water out for short periods.
Water does seep through sandbags, even when well-stacked and trodden into place, and this can be improved by using them in conjunction with plastic sheeting.
Sandbags can typically be purchased from landscape, building and hardware suppliers.
Keep sandbags dry and separate from sand (or soil) until needed. Do not store sandbags pre-filled, as they will begin to rot when put into storage filled with damp sand.
You should generally fill and place your sandbags before a weather event, not during.
If you are planning to use sandbags
You must remember:
- You will need a wall at least three bags high to keep out 20 cm of water at a standard door opening. See figure 1
- Each sandbag will need approximately 15 kg of sand or soil
It is easiest to use two people to fill them - They can take time to fill (approximately one hour to fill 12 sandbags)
- They can be difficult and heavy to handle
- Laying them can be very time consuming
- Unsupported walls of bags should only be placed up to three layers/rows for stability
- Use a pyramid shaped wall for stability if building an unsupported wall higher than 3 bags tall. See figure 2.
- It is difficult to place sandbags in water and particularly in running water, so plan to do this in advance.
- Use plastic sheeting in conjunction with sandbags for improved water resistance.
Property owners’ responsibility
It is the responsibility of property owners to take appropriate action to protect their property from flooding, so if you are in an area at risk of coastal inundation, please take steps to be prepared.
Sandbags are a temporary measure – if your property floods regularly, please seek advice on other flood-proofing options.
Filling sandbags
Garden centres have heavy soil or sand that can be used to fill sandbags, or use soil from your garden.
Don’t use gravelly or rocky soils, as this will let the water through. It’s easiest if two people are involved – one to hold the bag and the other to shovel the soil or sand in.
Handy tips:
Only fill bags to half or two-thirds full. This gives the soil or sand room to expand as it absorbs water.
Don’t tie or seal the bag – when you put it in place, fold the flap into a triangle and tuck it under the bag.
Building a sandbag wall
Place your first row of sandbags lengthwise and flat to the ground, butting each end to the next, folding the open end of the sandbag underneath. Stamp them into place to remove air pockets
Place the second row of sandbags on top staggering the joints, compacting each sandbag as you go
If you are using plastic sheeting, place it in front of the sandbags, between them and the water, then weigh down the bottom and top with extra sandbags.
Disposing of sandbags
Scatter the contents in your garden if bags did not come into contact with floodwater.
Please do not leave bags on the kerbside, as they will not be collected and may clog up drains.
Please contact your Council for advice on disposing of sandbags that have come into contact with contaminated flood water.
Do not try to reuse hessian sandbags as they are likely to rot and break during second use.
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