Underdrain

Definition

An underdrain is a perforated pipe drain installed in crushed stone beneath a slab to intercept groundwater and drain it away from the structure.

Purpose

The primary purpose of an underdrain is to manage groundwater and prevent it from accumulating beneath a structure. This helps to maintain the integrity of the foundation, prevent water damage, and reduce the risk of moisture-related problems such as mold and mildew.

Examples of Use

• Building Foundations: An underdrain system installed under the foundation of a building to redirect groundwater away from the structure.
• Roadways: Underdrains beneath roads to prevent water accumulation, which can lead to pavement damage.
• Landscaping: In gardens or lawns to manage excess water and prevent waterlogging of plants.

Related Terms

• French Drain: A trench filled with gravel or rock containing a perforated pipe that redirects surface water and groundwater away from an area.
• Sump Pump: A pump used to remove accumulated water from a sump basin, typically found in the basement of homes.
• Drain Tile: A system of perforated pipes laid around the foundation to direct water away from the structure.

Notes

Regular maintenance of underdrain systems is necessary to ensure they remain effective. Blockages or damage to the pipes can compromise the system's ability to manage groundwater properly.