Foundation drainage refers to any system designed to divert water away from a home’s foundation. Such systems are installed outside of the edge of the home’s foundation many areas the ability of the soil to support a foundation is affected by the amount of water in the soil too much water will cause the soils to be muddy and the foundation to sink and too much water and expansive soil will raise your homes foundation .
It is important to understand the terminology when it comes to discussing drainage systems. You want to be sure to take advantage of the options available to you and know what you are getting.Here is a list of Drainage terms.
Catch Basins
Typically 9″X9″ or 12″X12″ drains that are set in the ground. The top of the drain (grate) is located slightly below ground level. Surface water enters through the grate and collects in the box. A pipe is connected to the collection box below ground which directs the water away. Also referred to as Catch Basins.
COMBO DRAINS
A French drain and surface drain used in conjunction with each other in the same trench to remove excessive ground and surface water from around a foundation.
DISCHARGE
Refers to the disposal of the water collected by a French or Surface drain.
DOWNSPOUTS
Downspouts are vertical and extend down to ground level. Ideally, the water is piped off property, or let into the ground through seepage.
Most drainage problems come from the collection of rain water off of the roof into gutters downspouts, and oftentimes, the downspouts are conveying the water right onto the foundation.
FRENCH DRAINS
This is a trench covered with gravel or rock that redirects surface and/or groundwater away from an area. A French drain has perforated hollow piping along the bottom to capture water that seeps down through the upper gravel or rock. French Drains are common drainage systems, primarily used to prevent ground water from migrating under the foundation. Ground water under a foundation can cause movement beyond seasonal norms. French Drains are also used behind retaining walls to relieve hydrostatic pressure.
GRADE
A grade (also called slope, incline, gradient, pitch or rise) of the area around a foundation refers to the inclination of the ground from the horizontal. Negative grade means the slope is towards the foundation. Positive grade, or sloping away from the foundation, is desirable to help prevent unwanted foundation movements.
SUMP PUMP
This is a pump used to remove water that has accumulated in a water collecting sump basin. Sump pump systems are used when a drainage system is unable to be discharged with gravity alone. In that case, water is channeled to a collection area known as a sump. Once the collection water reaches a certain volume a submersible pump is used to pump the water away.
SURFACE DRAIN/YARD DRAINS
Surface drains consist of a series of collection boxes or catch basins and a solid pipe. The are designed to collect and transmit water that is accumulating on the surface (around a foundation.)