Water Drainage Solutions
Poor water drainage around residential foundations causes millions of dollars in damages every year. Water is the major enemy of your foundation. If there is too much water foundation bow, rise, and buckle. Controlling water and waterproofing will prevent this water damage and help maintain the structural stability of homes. Keeping water drained away from foundations is important for many reasons. First, is to protect occupants and keep them dry. Maintaining a consistent moisture level in the soils supporting the foundation is crucial to prevent settlement, differential movement, and heaving. Additionally, building codes mandate the necessity for proper drainage.
Reasons for Water Drainage
Gutters – Maintain roof gutters diligently. Direct downspouts below the soil surface through rigid piping to popup emitters, drywells, or daylight. Maintaining proper sizing and proper slope of the discharge is very important.
Trees – The US Housing and Urban Development Department recommends planting trees at a distance equal to their mature height or farther. This prevents excessive moisture draw away from the foundation.
Soil Moisture – Moisture undergoes a triangular pattern of gain and loss beneath the foundation. The soil loses moisture along the edges, then downward, and towards the middle of the foundation. It replenishes its moisture in the same manner.
Surface Drainage – Controlling surface rainwater is critical to controlling soil moisture and preventing foundation damage. To encourage water drainage away from the foundation, the ground surface should have a minimum slope of 1/2″ per foot for a distance of 10′.
Channel Drains – Channel Drains create a pathway for water coming off of hard surfaces. Home owners frequently have channel drains between driveways and garages. This helps trap water and direct it toward a catch basin or emitter.
Foundation Drainage Boards – Install drainage boards or dimple boards on the exterior of concrete walls. This helps guide water toward the perimeter drain tile. This semi-rigid material, placed over a waterproofing membrane, features “dimples” or ridges that divert water away from the foundation and toward the drain tile.
Subsurface Drainage – Construct perimeter foundation drains using rigid drain tile, connecting them to either a sump pump system or directing them to daylight.
Drain Pipe – Position drain pipes alongside the footing, maximizing drainage by placing them externally, internally, or both. Drain pipe should have a slight slope toward the outlet with no low spots.
Building Codes – The International Residential Code requires drain pipe around all concrete or masonry foundations that retain earth and enclose habitable or usable spaces below grade. The IRC goes on to mentions approved products such as ASTM approved rigid drain pipe.
Optimizing Water Drainage in Foundation Work
Whether foundation repairs or waterproofing work is being done, water drainage must be addressed before the job is complete. Water poses a threat to foundations. It’s crucial to prevent moisture from entering the basement or crawlspace for the proper functioning of your foundation.
Modern drainage systems like the types ECP supplies, incorporate geotextile filters and an aggregate that retain and prevent fine particles of soil from passing into and clogging drain pipes. In civil and environmental projects, we use specially manufactured synthetic textile fabrics known as non-woven geotextile fabrics. In a standard drain application, these fabrics are placed along a trench, filled with coarse stone around a drain pipe. The geotextile material is then folded over the top of the stone fill, and the trench is backfilled with suitable soils. Groundwater will seep through the geotextile fabric and then through the stone to the drain pipe. The drain pipe then provides a pathway for the water to travel to a catch basin, drywell or sump pump system.