Sandbags can be useful in redirecting storm water and debris flows away from your home. It is important that sandbags are properly filled and maintained. See below for information on filling, laying, and storing sandbags, as well as sandbag limitations. Click here for information on where to find sandbags.
What to expect
There are limits to what sandbags can do. Remember, sandbags will not seal out water. Sandbags deteriorate when exposed to continued wetting and drying for several months. If bags are placed too early, they may not be effective when needed.
Sandbags are for small water flow protection — up to two feet. Protection from larger flow requires a more permanent flood prevention system.
Sandbags that are exposed to contaminated floodwaters may pose an environmental hazard and require special handling. Be sure to consult with your local environmental protection department before disposing of used sandbags.
How do I fill the sandbag?
- It is preferable that you only use sand to fill the bags.
- Soil is not usually recommended.
- Sandbags only need to be filled to 2/3 full.
- Do not over fill the bags as they can become too heavy to carry. A filled sandbag can weigh 70-75 lbs.
- Do not tie the top of the bag. The top of the bag may be tied for transport purposes only.
Sandbags mixed with cement
For a more durable bag with increased effective life, mix 10 parts of sand or soil with 1 part of cement. The materials can be mixed and placed dry. After all bags are in place, a light sprinkling of water is recommended. Please note, this technique is only effective with burlap sandbags and will not work with plastic sandbags.
- Sandbags will not seal out water.
- Sand and soil filled burlap sandbags deteriorate when exposed to continued wetting and drying for several months. If bags are placed too early, they may not be effective when needed.
- Sandbags are basically for low-flow protection (up to two feet). Protection from higher flows require a more permanent type of structure.
Do not use straw or bales of hay in lieu of sandbags. They do not perform as well as sandbags and may be washed away.
How do I lay sandbags?
- Place down a layer of plastic sheeting to act as the water-proofing barrier.
- Lay sandbags like brickwork on top of the plastic sheeting.
- Limit placement to three layers unless a building is used as a backing or sandbags are placed in a pyramid.
- Fold the top of the sandbag down and rest the bag on its folded top. Take care in stacking the sandbags.
- Start at one end and work to the other end.
- Ensure the unfilled top part of the bag is covered by the next bag.
- Tuck flap under the bag at the end of the row.
- Tamp each sandbag into place, completing each layer before you begin a new layer. Clear a path between buildings for debris flow.
- Stagger rows so that the joints do not line up.
- Most standard homes and buildings on a concrete slab can be protected with less than 25 sandbags.
Storage of sandbags
If keeping a stock of sandbags, be aware that they can rot if left wet and damp. Be sure to store them in a dry place out of the sun.