Many homeowners will use a retaining wall to form terraces which hold back soil in a sloping yard. Water damage such as flooding can wash out soil around the wall, weakening the structure which may cause it to collapse. To avoid water damage in retaining walls, it is required to perform a suitable drainage layout.
The process for adding drainage to an existing retaining wall is the following:
- Excavate A Trench Along The Wall To The Outlet Point
- Ensure to have positive gravitational flow toward the outlet
- Place the crushed stone as the bed for the pipe.
- Perform the necessary coupler connections of the piping
- Place an end cap in the piping as needed
- Backfill the pipe with the crushed stone up to 15 centimeters (6 inches) above the crown of the pipe
- Compact The Soil Of The Surface when you have finished.
The goal after all is to enhance the life and performance of your retaining wall. Before you dig, be sure to contact your local utility notification center. Find out where any underground utility lines might be. They’ll send a professional to mark the underground lines so that you can safely start your project.
Materials Required To Add Drainage To The Retaining Wall
Before you get started, some materials you may need are
- Perforated pipe with or without a geosynthetic sock
- Pipe couplers
- Outlet fittings
- End caps
- Non-woven geotextile,
- Stone for backfill of a size 15/25 mm or about 3/4 inch.
Be sure to determine the type of pipe needed to handle the expected flow for your project.
Perforated round pipe or panel pipe can be used for a proper drain line.
Step By Step Process
Step 1 Excavate A Trench Along The Wall To The Outlet Point
The first step is to excavate a trench along the wall to the outlet point. The outlet for your project might be any of the following options:
- a culvert (Durchlass)
- discharge through the wall
- a retention pond
- or curbside
Step 2 Ensure to have positive gravitational flow toward the outlet
Ensure that there is enough positive flow toward the outlet to allow for adequate drainage.
Step 3: Place the crushed stone as the bed for the pipe.
Place and compact crushed stone as bedding for the pipe and the inlet structure. If there is a concern about keeping dust and small particles of the stone backfill from entering the perforated pipe, simply cover the pipe with a geosynthetic sock before installation to help prevent this.
If the soil you are working with is sandy, lay the geotextile into the trench so that it does not migrate into the stone backfill.
Allow for enough material to cover the sides of the trench and to overlap on top of the stone backfill a minimum of 15 centimeters (6 inches) above the crown of the pipe (the crown of the pipe is simply the top of the pipe) .
Step 4: Perform the necessary coupler connections of the piping
Make any necessary fittings or coupler connections to reach the designated outlet point
Attach the outlet to the existing drainpipe. Lay the pipe along the way towards the outlet point.
Step 5 Place an end cap as needed
This step is very simple. Place an end cap if needed.
Step 6 Backfill the pipe with the crushed stone up to 15 centimeters (6 inches) above the crown of the pipe.
When the pipeline is finally in place, backfill with crushed stone up to 15 centimeters (6 inches) above the crown of the pipe when using corrugated pipe.
Overlap the geotextile and then backfill again as you wish afterwards.
Step 7: Compact The Soil Of The Surface
Compact the topsoil as necessary. This is not a mandatory step
Installing retaining wall drainage is not the only thing you can do to control erosion and ensure proper drainage around your home but it is very important anyway.