First, you can install a perforated drainage pipe. This kind of pipe is installed along the inside or backfilled at the bottom of the wall. A perforated pipe has holes throughout it that allow the water to trickle down into the pipe and drain out into the gravel and dirt around the retaining wall.
Can Weep Holes Be Added to an Existing Retaining Wall? Yes, weep holes can be added to existing walls, but it requires careful drilling and consideration of the wall's structural integrity.
In masonry walls, a weep hole may be formed by leaving a spacing in a vertical joint. For concrete walls, the weep hole is usually formed by casting in a short length of plastic pipe, laid slightly sloping downward towards the front of the wall.
Hydrostatic Pressure and Wall Failure
When water isn't properly drained, it can accumulate behind the wall, exerting pressure on the structure. This pressure can prompt the wall to shift, crack, or even collapse. To avert such failures, it's crucial to have adequate drainage behind the retaining wall.
I recommend using post hole diggers or auger to excavate holes every 5-ft directly behind the wall. Fill these holes with drainage stone. At the front face of the wall, drill a holes at the bottom of wall aligned with every column of drainage stone.
Absolutely! Even a 2-foot retaining wall needs an effective drainage system. Without it, water can build up behind the wall, leading to pressure that might cause the wall to lean or even collapse. All walls need systems to manage water effectively, preventing damage over time.
A drainage pipe might be needed if: The retaining wall is at least four feet high or taller. Clay or other poor draining soils are behind the wall.
Soil saturation is the most common external factor that causes retaining wall failure, but there are many ways to prevent it.
Filled Wall Blocks Promote More Efficient Drainage
Rainwater, snow, and ice can all accumulate inside precast retaining walls composed of hollow blocks.
Don't Skimp on Gravel Amount
Add an angular aggregate — clean, crushed stone or gravel between 1/2- and 3/4-in. — as a base under the retaining wall and as back fill behind it.
As an alternative to weep holes, most new construction will connect the drainage zone to a perforated drainage pipe located behind the base of the wall outfalling to a manhole.
First, you can install a perforated drainage pipe. This kind of pipe is installed along the inside or backfilled at the bottom of the wall. A perforated pipe has holes throughout it that allow the water to trickle down into the pipe and drain out into the gravel and dirt around the retaining wall.
In conclusion, when designing a drainage system for a segmental retaining wall, an all-around perforated pipe* is the best choice. It allows for more efficient drainage, distributes water more evenly, and helps to prevent water from pooling and exerting hydrostatic pressure on the wall.
Weep holes are therefore not necessary. However, weep holes are required when the structure is located below the water table, there is no water plastering, and the additional water pressure acts on the structure that is greater than the saturated pressure or the earth pressure.
Discover how the right retaining wall can reduce soil erosion, improve water drainage, and transform your property. Depending on the material, soil, and groundwater, a permanent retaining wall can last anywhere from 25 to 100 years.
Sometimes retaining walls are designed as cantilevers. These typically include reinforcement and rely on the combined strength of the concrete and reinforcement to resist bending at the base of the wall. In that case, plan on waiting seven days before placing the full depth of backfill.
Applying a liquid membrane over the retaining wall will grant an excellent level of waterproofing for your retaining wall. It creates a rubberised coating over the chosen area, which prevents water penetration. Using a good quality liquid membrane can ensure protection for up to ten years, and longer in some cases.
Don't Forget To Backfill Behind Your Retaining Wall
Neglecting to backfill properly can lead to reduced support, increased pressure on the wall, and the possible collapse of the wall.
In order to provide proper drainage, at least 12 inches of granular backfill (gravel or a similar aggregate) should be installed directly behind the wall. Compacted native soil can be used to backfill the rest of the space behind the wall.
Drains or a drainage channel typically built into the landward toe of an embankment or the downstream toe of an embankment dam. For the purpose of capturing seepage from the embankment and conveying it safely away from the structure.
Do you need drainage behind a retaining wall? Yes, which means you need backfill too. This backfill is the soil that's located in the first 12 inches of space right behind the retaining wall in order to have proper drainage, and it can be either gravel or crushed stone.