Backfilling trenches and foundations

Understanding the steps to backfilling trenches and foundations will give you the knowledge you need to ensure the contractor you hired is providing you with quality work and service.  What is backfilling? Backfilling is the process of replacing lost material around a foundation after excavation.  Before a foundation can be poured a trench or pit will have to be dug to allow room for the foundation to be placed.  Once it has been placed, you’ll need to backfill the area surrounding the foundation to help provide it with support.  Concrete is strong and durable, but only when properly supported.  If it isn’t supported then it will crack, or even break, which can cause major structural damage to a building.  While backfilling might sound simple enough, if it isn’t done properly it can end up causing damage to a building’s foundation, which can be a very expensive problem to repair.

Choose The Right Backfill Material

The easiest option when backfilling around a foundation is to use the original soil that was excavated to create space for the foundation to be installed.  But just because something is the easiest solution does not mean that it is the best solution.  If you use soil that has too much organic matter in it, it’s going to compact more than regular soil.  This can cause sinking, which can cause structural damage.  If you use soil that has large boulders in it to backfill, these boulders will shift and move, which will cause the soil to sink, which can also lead to structural damage.  It’s important to choose coarse grained soil for backfilling.  Is this possibly another expense? Yes, but in this case, it’s worth it to avoid the headaches that can result if the backfilling process isn’t done correctly.

Reinforce the Strongest Parts of The Foundation First

Sometimes when a construction or work crew is under a tight deadline there may be a temptation to try to rush things to get them done quickly.  Backfilling around a foundation may appear to be a simple process, and there may be a thought of just working quickly to get it completed.  But this would be a mistake.  Backfilling should be started at the strongest point of a foundation, then slowly built up around the perimeter of the foundation.  Placing too much soil around any one area of the foundation at once will put stress on it, which can easily lead to a collapse.

After about six to eight inches of soil have been placed it should be wet and compacted before moving on.  While using wet backfill material is a problem, that’s a different situation than wetting the material evenly once it has been placed.  After you have built up each layer of soil until the entire foundation is surrounded you will have completed backfilling around the foundation.

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