Why Do I Need Drainage Behind a Retaining Wall?
Drainage is a critical aspect of any retaining wall project, as excess rainwater and runoff can put undue stress on its structure and potentially lead to its collapse. Without adequate drainage systems in place, seasonal rainfall and runoff could put undue strain on its integrity, possibly leading to its downfall and collapse.
To ensure proper drainage, all retaining walls should include backfill that extends 12-in behind each block and be filled with gravel. We recommend also placing and pinning filter fabric above and below drainage stones and topsoil layers.
Though they might not seem glamorous, weep holes are essential components of retaining walls to counter hydrostatic pressure. A wall must withstand the weight of its soil while being held back by walls that contain it; weep holes allow excess water to escape and relieve pressure by being regularly spaced across its face in both horizontal and vertical directions – for instance in grid patterns.
Weep holes should not be seen as permanent solutions. Instead, they must be checked and cleaned regularly in order to remain clear of debris, rodents and pests; in case they become blocked with mortar or dirt they must be replaced in order to allow water to pass freely through.
As well as weep holes, it is also essential that retaining walls have an effective drainage system in place. A pipe running along the wall to redirect surface water away helps reduce hydrostatic pressure against it and decreases chances of seepage into homes.
Prior to building your retaining wall, a drainage system must be put into place. This enables installers to properly grade the area and direct water toward its drainage pipe. Utilizing such a system during construction can save both money and headaches; using one will help ensure that your wall is constructed correctly without leaks at its base.
Location and size of drainage pipe depend on the type and soil surrounding retaining walls. In cases with very steep slopes, digging trenches with pipes to channel water away could be required; though more expensive than simply extending drainage stones further along the wall’s base. This option also saves on dealing with heavy, unstable soil conditions that might otherwise exist.
Another effective method for draining retaining walls without weep holes is using perforated pipe. Once installed on top of gravel beds, water can easily percolate through it and exit through its bottom outlet pipe to relieve hydrostatic pressure on the retaining wall.
Any retained wall should have drainage to reduce lateral pressure behind it and the associated shift of soil or wall damage. Effective drainage also decreases erosion caused by water flowing over or through its face and through it.
Drainage systems on retaining walls can make them less likely to collapse in areas with heavy rainfall like Alabama, Florida, Louisiana and Tennessee. While drainage may seem expensive as part of their project, in reality it reduces overall costs significantly.
To facilitate proper drainage for retaining walls, we advise using perforated pipe and drainage stone. These will enable water to run off through the pipe into gravel or dirt buried around your wall more quickly reducing how long your yard remains saturated and making garden irrigation much simpler.
When installing your drainage system, ensure proper backfill is used. This includes at least 12 inches of crushed or gravel covered by topsoil; additionally, backfill should stop frost heaving by ensuring a level surface for backfill.
if your retaining wall is too tall to install a pipe drain, a French drain may be the perfect solution. A French drain consists of an inward-sloping trench filled with gravel that drains water away through pipes; it is an effective way to keep long retaining walls stable while eliminating standing water that could potentially lead to mildew or mold growth.
An alternative option for drainage system installation is a toe drain, which consists of a perforated pipe running along the front of your retaining wall and venting out through its face. It is best to extend it 30 to 50 feet from its location to avoid trips while periodically testing its efficacy.
Retaining walls without adequate drainage are at great risk of suffering catastrophic damage or collapse if their soil becomes saturated by rainwater, as its weight puts undue strain on them and puts enormous pressure on their foundations. Without adequate measures in place to allow water through and drain away its excess weight, retaining walls with improper drainage could suffer irreparable harm or collapse altogether. One effective solution would be incorporating features that allow excess weight to pass through; these would ensure water passes freely away and carry away its weight more effectively.
All retaining walls require some form of drainage system for effective operation, especially those built of concrete or cinder block that do not feature natural joints like segmental blocks or wood walls do. A drainage solution is especially necessary if the wall exceeds four feet in height or was constructed in soil that does not drain well, such as clay soil.
As part of your efforts to ensure proper drainage, one key thing you can do to make sure that it works effectively is watching your retaining wall during a heavy rainfall event and taking note of where water collects and how fast it drains away so that you can plan to incorporate proper drainage features in its design.
When creating a drainage system, selecting an appropriate type of gravel for its top layer is key to keeping costs under control and still creating an effective surface that supports soil loads.
Pink quartz gravel is often the go-to choice, providing light hues with excellent texture. Northern granite river rock also makes an attractive choice as it has more of a natural aesthetic; finally white dolomite crystalline stone works beautifully in modern landscape designs.
Once you have selected a top layer, it is crucial to add a thick layer of gravel backfill at least 6 inches thick to cover all ground under your retaining wall. Perforated pipe can then be added near its base in order to transport water away from soil into drainage systems.
Make sure your drainage pipes are well ventilated to avoid clogging, plant vegetation at the base of your retaining wall to help absorb any extra water, and periodically inspect your drainage system to identify and clear away any blockages or debris in its pipes, inlets and outlets.
Proper drainage of retaining walls cannot be overemphasized. Without it, rains and other forms of moisture could pose serious threats to their structure and any landscaping features behind it, leading to costly damages for surrounding property owners and requiring costly repairs to the wall itself. A drainage system allows water to escape while decreasing hydrostatic pressure behind it.
An improperly draining retaining wall can become unstable or collapse under heavy rainfall, creating immense lateral pressure against it and eventually leading to its collapse. A drainage system must be constructed within the wall in order to safely transport away excessive moisture during stormy weather and prevent this situation from reoccurring.
Your retaining wall, whether composed of segmental blocks, timbers or concrete is in need of drainage provisions for its long-term success. If this becomes evident during its construction process, be sure to consult a professional landscaping contractor as soon as possible; adding drainage features may cost an extra few thousand dollars, but they could save money in the form of reduced failure risk and preventative repairs in the long run.
If the ground under your retaining wall is wet when excavating for it or there is standing water even during dry conditions, this indicates groundwater presence at your project site. To reduce saturation of clay-type soils used as backfill, have your landscaping contractor install drains at installation time to drain away excess water – drains will carry it to each end of your wall so that it can escape without creating pressure build-up behind it.
As part of your efforts to strengthen your drainage system, planting vegetation around the base of your retaining wall can help absorb any excess water that overflows over its top. Swales – shallow drainage ditches designed to collect surface runoff and direct it away from your wall – may also help prevent groundwater accumulation at its base. Regular inspection of your drainage system is important to identifying any blockages or clogs which may arise and clearing them out immediately.