Sandbags and Sandbag Walls
Sandbags are used for ballast, securing objects to the ground and flood defences. Like everything else in life there's a right way and a wrong way to do things. Ditto with building a sandbag wall. Here are a few guidelines you should follow:
1. Be prepared.
The old boyscout motto still holds true. Having 20 empty sandbags in the garden shed is little use. Consider if you get a flood warning how will you fill them? Do you have sand on your property? Can you get to a beach or obtain sand in time? Will the tide be in when you get there? How many do you need? Sandbags tend to retain contaminents in water so you really should have a plentiful supply of them if you think you will be fighting flooding for any period of time. if you have filled sandbags keep them out of the rain and sun to preserve them longer.
2. Solid Foundations
You wouldn't build a block wall on an uneven foundation and sandbag walls are no different. Building over bumpy ground will give your wall a shaky feeling and if your building flood defences risks letting water in beneath your wall. Get rid of any major stones in your path, or fim up dips with half sandbags. If your building flood defences make sure any foundations you lay won't get washed away by strong flowing waters or your wall will look silly, and you even sillier.
3. Fill the sandbags half full.
Place the bags lengthways and parallel to the direction of the water flow. Tuck the opened end under the filled half of the bag and position it pointing into the water flow. Ensure it is bedded in against any abutting objects such as doorways or walls.
4. Pretend your laying bricks.
Each sandbag should overlap the one below by half.
5. Stamp on them to eliminate gaps.
6. If you are building a wall that is more than 3 layers high you need a stronger base. A good rule of thumb is to have a base than is three times as wide as the height.
7.Check for wear and tear.
If your sandbag wall is in place for a few days, check for wear and tear when you can. Fast flowing flood waters can batter objects withing them against your wall. Replace any sandbags that show signs of wear and tear. If its possible to access the wall during floods, push any debris building up outside the wall away to relieve pressure on the wall.
If you are barricading your doorway against flooding, a good idea is to build a sandbag wall on the outside. Between the frame a sheet of boarding is then placed aand sealed with water proof sealant around the edges, eg. silicone or putty. Plastic sheeting is often draped over the sandbag wall to improve water resistance. This acts as a double barrier. In cases of severe flooding, old houses are particularly at risk due to wooden flooring with little concrete bases.
Take accound too of severe flooding that you may require sandbags for window ledges, back doors, garden shed doors etc.
