Tips for sandbagging your home

by Mar 14, 2022Preparation

 

    There has been a flood warning and you know you are sandbagging your home again.  Getting through to the emergency services may be difficult as they may be too busy to help. 

    You may be told how to sandbag your own home, where to get sandbags from or you are put into a long queue for help.  That is if you can get through to the emergency services in the first place as everyone is ringing them. 

     There is a lot of information out there on how to do a basic sandbagging task (see further reading below) which uses the standard hessian bag, sand and is put in place by an emergency services member. 

    This may work for small localised flooding but when we are talking large scale flooding resources and emergency service personnel are stretched far and wide preparing for the scale of the disaster.

    This article covers some useful information that the emergency services may not have time to tell you when it comes to sandbagging your home.

    Remember when sandbagging your home

     Sandbags are not waterproof

     What?  Sandbags are not waterproof, even if you are using a plastic bag the water can still seep around each bag.  The standard hessian sandbag lets water into the sand which only slows the water flow.  And then there are the crevices that are around each sandbag letting more water through, even if you jump all over them.

     They should be used in conjunction with

    • Plastic sheeting
    • Tarpaulins
    • Large plastic garbage bags
    • Or similar waterproof sheeting

     Sandbags placed over floor wastes and in toilets will still benefit from a garbage bag being placed under the sandbag.

     

     

     

     

    Emergency Kit

     

    What is the role of a sandbag?

     Sandbags can be used for various reasons when it comes to protecting your home during a flood event.  The main purpose of a sandbag is to act as a heavyweight holding down a waterproof material or deflecting flowing water and mudflows. 

     Redirect water away from your home

     Building a line or small wall of sandbags can change the course of the flowing water.  Water can be deflected across a slope by placing the wall at a slight angle downhill.  This will help homes built on slopes or terraces.

     Stand-alone walls should be angled front and back to prevent them from falling over.  Weave the plastic sheeting up the middle of the wall to prevent water from passing through the wall.  Overlay the sandbags like brickwork to make the wall stronger.

     Don’t build the wall too high. 

    One cubic metre of water (1m x 1m x 1m) equals one ton of water.  Sandbag walls over a metre high will move if they are trying to hold back a lot of water as the wall is not engineered to hold the weight.

     If you are trying to prepare for a 3-metre flood the wall will need engineering as the force of the water will move a DIY sandbag wall.  Don’t go over 2-3 feet in height.  Larger walls take A LOT of sandbags too.

     Deflect street water

     If the road is flooded and vehicles are pushing water up into your home you can build a wall to deflect the water back onto the road.  In an ideal world, cars would not be driving through the floodwater and the water wouldn’t be getting sprayed into your home.

     

     

    Emergency Kit

     

    Reduce water entering your home

     We commonly think of this when we think of sandbags, the line of sandbags across the doorway.  I say reduce as they are usually quickly put together and don’t go 100% around your home so there could be a crack in the floor or wall letting some water in. 

     And then there is the water that can enter your home from the roof or guttering not handling the water load.  Banked up sewerage and stormwater can enter your home through the toilet, floor wastes, shower or bath.

     Tips for sandbagging your home

     Only fill the sandbag two thirds full.  This makes it easier to reshape and gives you a flap to lay the next sandbag on top of to add strength to the wall.  It also makes it lighter and easier to carry especially if the sand or soil is wet.

     Use the soil you have on hand. A lot of online information will say you have to use sand.  Sand is good as it doesn’t dissolve and is heavy but, in an emergency, you use what you can find.  Organic materials such as compost and mulch are no good as it is too light and floats.  You want the weight and something that can be moulded to fill in the gaps.

     If your door opens outwards and you still want to get into your home build a U-shaped wall away from the building to allow the door to open.  Place the plastic sheeting behind the front sandbags and then place some more sandbags behind the sheeting to hold it in place.

     To keep the plastic in place while you fill the sandbags.  Position the plastic sheeting so that it runs along the ground away from the wall and up the wall higher than the flood hopefully.  To hold it in place, duct tape the plastic to the wall in sections to stop it if falling down.

     Don’t have enough sandbags.  If you are running short on sand or sandbags you can combine them with other heavy objects such as logs or concrete.

     Use what holds soil.  If you run out of sandbags or cannot get out to get more from the local supplier you can use anything that holds soil.  Remember they are not waterproof.  You can use –

    • Empty fertiliser or potting mix bags (buying a full back of potting mix and putting that across your door will not be heavy enough and you will still need the plastic sheeting).
    • Pillowcases (they won’t be any good afterwards)
    • Grocery bags
    • Garbage bags
    • Animal feed bags
    • Purpose made sandbags in hardware, safety shops (expensive and sell out quickly)

     Don’t fill your bags before the season.  Organic materials such as hessian or plastics that break down in the environment will rot out before you need them.  Any contact with water and soil microbes will start the decay process.  Keep them dry and out of the sun until needed.

     They are not reusable.  After the flood has gone you can’t empty them or move them to the back of the shed for next time.  They have been exposed to chemicals, microbes, oils, sewerage, fungi and water.   Some authorities will tell you to empty them into the garden others will have rules on where you are to dump them as they may be contaminated.

     Sandbagging your home takes a lot of time, energy and resources.

    If you have a short warning of a big flood, you need to spend your time preparing for evacuation and rescuing your valuable items (don’t forget pets and family). 

    More long-term warnings or the flood is not going to be very high can give you time to sandbag. 

    Large floods need to be fought at a government level.  Follow the safety directions of the local authorities regarding evacuation.

      

     

     The sandbagging in this picture is more suited to light flooding or spray from the street due to it’s minimal construction.

    Summary

    Ensure you are prepared for flooding before it hits.   Listen to your local media or radio for possible locations to get sandbags.  If you are unable to get them from elsewhere you may have to improvise at home.  Sandbagging takes a lot of time, energy and resources.

     If you are not physically able to sandbag your home, see if family, friends or neighbours can help.  And if that is not a possibility contact the emergency services stating you are old or disabled and unable to rescue yourself.

     In the event of a flood don’t just rely on sandbags to keep you dry. 

    • Still prepare your home by lifting appliances and furniture,
    • Securing your valuables and documents. 
    • Don’t forget to have a plan,
    • Emergency kits and
    • Escape route if needed.
    • Have a plan for flood clean up after the event.

     Download your FREE 7 Essential emergency kits checklist.

     Further reading

    DIY Sandbagging

    https://www.sunshinecoast.qld.gov.au/Living-and-Community/Community-Safety/Disasters/Be-Prepared/DIY-Sandbagging

     

    DIY Sandbags to protect your home

    https://www.qfes.qld.gov.au/sites/default/files/2021-05/DIYSandbag.pdf

     

     

     

     

     

     

     

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