The foundation is likely the most important element of any building, providing a stable surface that supports the rest of the structure. If it is well-designed, it should stand the test of time, but poor site preparation can lead to standing water and structural damage. To protect the stability of your home or commercial space, the guide below looks at the difference between positive and negative drainage.

Positive Drainage

During the site preparation phase of construction, your excavation contractor will take steps to ensure water runs away from the foundation of your building. This is known as positive drainage and may require significant alterations to the property to achieve. For instance, if your property is situated below a hill, your contractor may create depressions in the soil to direct rainwater around and away from the excavation.

Negative Drainage

Any surface issues that cause water to flow toward the building is considered negative drainage, a condition that could carry serious consequences. Even small dips in the ground around the foundation can create pockets that may fill with water, which eventually works its way into the concrete, cracking the structure and potentially destabilizing the entire building.

How Excavation Contractors Account for Drainage

The proper drainage techniques for any building site depend on the surface grade and composition of the soil. Very loose ground might require compacting to prevent settling after the structure is built, which alters the grade of the surface. Your site preparation contractor may also decide to use aggregate material as backfill instead of soil to allow subsurface water to drain away from foundation walls.
 

Since 1995, Valley Excavating has been earning the trust of contractors and homeowners throughout Montana’s Flathead Valley, Kalispell, Whitefish, Columbia Falls, Bigfork, and Lakeside areas. With their extensive expertise and commitment to their customers, you can depend on their site preparation experts to deliver quality results on every project, large or small. Visit their website now for an overview of their services, follow their Facebook for samples of their work, or call (406) 857-2086 to request a free quote today.