A retaining wall makes it possible to create terraces of usable land on sloped properties. It also serves to delineate property lines and discourage neighbors from using your yard without permission.
A retaining wall requires careful planning, and experts are essential to ensure the project is carried out correctly. This includes meeting building codes and adhering to regulations specific to your area. Retaining Walls Charleston SC contractor will help you get the basics done.
Design
Whether you are planning to build a small retaining wall on your own or enlist the services of a contractor, there are many aspects to consider. A thorough analysis, including site-specific constraints and the ability to utilize space effectively, is essential to a successful outcome. A retaining wall requires proper excavation and foundation preparation, base course installation, interlocking block construction and compaction, drainage features, and structural reinforcement. It is also crucial that you check local building codes and regulations to determine if you need a permit or must adhere to any guidelines for your area.
The design of a retaining wall should take into account the type of soil to be retained as well as its bearing capacity and potential surcharge loads. It is also necessary to examine the site conditions and groundwater issues. Structures that require a piled or rigid foundation may be more costly than those that do not. The cost of materials will be a major factor in the final price as will the degree of maintenance required.
There are several types of retaining walls that you can choose from, depending on your budget and aesthetic preferences. Popular options include concrete blocks, bricks, and timbers. Each has its unique advantages but they all must be considered carefully about the function(s) of your retaining wall.
A retaining wall that is designed to retain soils at two different elevations must be capable of resisting lateral pressures from the retained soil and any other surcharge loads. This will typically involve the use of a footing system with a shear key at the toe, which must be designed to control the maximum pressures acting on it.
To determine the appropriate footing size and geometry for your project, it is important to consult with a professional engineer familiar with retaining wall design. A detailed analysis, including a site visit and soil testing, is required to make an informed recommendation. An engineer will evaluate the available space, site-specific constraints, and the ability to implement a structure that meets both your functional and aesthetic goals.
Materials
The basic materials that make up a retaining wall vary according to function, cost, and height. Decorative walls can use almost any type of block or stone that the owner likes, while those serving a structural purpose must be designed and built with durable, long-lasting materials suited to the site conditions.
To start building a retaining wall, first excavate the area where it will be installed. Line the trench with landscape fabric and fill it with gravel or crusher-run base material. Compact thoroughly, adding more base as needed for stability.
Install perforated drainage pipe, if necessary. Next, backfill the space behind your wall with a 6-inch layer of granular backfill (gravel or similar aggregate). This helps to prevent soil erosion and ensures that water can drain away from the retained area.
Lay your retaining wall blocks, starting with the bottom course. Using a torpedo level, be sure that each block is straight front-to-back and side-to-side. To help ensure that the blocks lock together in a proper “Running Bond” pattern, each row of blocks should be set so that there is a minimum of 1” of space between each block. For a more sturdy wall, you may also choose to add a layer of geogrid between each course of blocks.
Continue to build the retaining wall, adding courses one at a time and tamping down each section as you go with a hand tamper. Be sure to use good-quality gravel for your backfill, not dirt. Dirt swells when it gets wet, placing unnecessary pressure on the retaining wall. Gravel, on the other hand, will not swell and is less likely to damage your retaining wall.
When the retaining wall is complete, top it with a 6-inch layer of native soil to encourage plant growth and improve the aesthetics of the project. Be sure to check with your local building or zoning authority for any additional requirements for the construction of a retaining wall in your particular jurisdiction. Also, be sure to call a contractor before beginning any construction to have any utility lines marked.
Installation
Retaining walls have to support their weight and resist lateral pressure from the soil they retain. These pressures can become intense and lead to buckling over time, especially in saturated ground or poorly designed structures. Water is the number one enemy of retaining walls, as it causes erosion around the base and saps strength from concrete and mortar. Poor drainage, clogged drains, and freeze/thaw cycles can also be damaging.
A good retaining wall is an investment that requires careful maintenance to protect the structure and extend its lifespan. Close inspection should be done to check for deteriorated joints, cracks, bulging, shifting, and crumbling of the material. If a wall is damaged, repairs can be made by using solutions like helical piers or wall plate anchors, depending on the condition of the structure.
The first step in building a retaining wall is to lay a course of blocks. Using a carpenter’s level, make sure the block is perfectly level left-to-right and front-to-back. If not, use a hammer and chisel to remove the flange from the blocks so that they sit more evenly on the ground. When the first row is complete, use a tool to cut half blocks for the second and subsequent rows. This staggers the blocks so that they do not align with each other in a traditional bricklaying pattern.
Continue to build each tier of the retaining wall, shoveling in backfill as you go. Make sure to add gravel before each new tier, and tamp it down with a hand tamper to help it compact well. Be sure to install drains behind the foot of each tier, as well. Drainage is crucial for preventing hydrostatic pressure from building up in the soil and pushing against the retaining wall.
Finally, all retaining walls should lean into the hill they should retain at least 1 inch for every 12 inches of height. This is called the batter. Taller retaining walls should be tied to the hillside with tiebacks, also known as deadman anchors. These are 6-foot-long, T-shaped steel rods buried in the hillside and attached to the wall with a hex nut.
Maintenance
Retaining walls aren’t just good for preventing soil erosion, they also add value and beauty to a property. But they’ll only last if they’re properly maintained. Regular inspections and proper care can keep them structurally sound and looking great.
A retaining wall’s quality of construction and the materials it’s made from have an impact on how long it will last and how much maintenance is needed. Poor materials and construction techniques can lead to early deterioration or even failure of the structure. In addition, water seepage can damage the integrity of a retaining wall by causing rot or even corrosion of steel elements inside the structure.
In addition to quality construction, a retaining wall must be adequately anchored and supported to prevent failure and erosion. In many cases, this requires the use of anchors, which are cables or other stays anchored in the soil or rock behind the wall. These can be driven into the material using boring or often, injected with pressurized concrete that expands at the point of penetration. Anchors can be used in combination with other methods, such as geogrid reinforcement layers, to provide additional support and stability.
Although retaining walls are built to withstand lateral pressure from the soil, excessive pressure can cause them to deform or collapse. In many cases, this is caused by factors such as inadequate drainage, adding too much load to the retained soil, or changing landscape conditions.
The best way to prevent these problems is to check for early warning signs that the retaining wall may need repairs. These include bulging, cracks in the blocks or mortar and gaps between them. In addition, if a wall has pooling water or other evidence of soil moisture buildup, it’s important to take action immediately.
When these signs are detected, the best course of action is usually to call a professional for repairs or replacement. These professionals can assess the problem and determine the most effective solution, which might include repairs or tiebacks to stabilize the wall, as well as the installation of new drainage features to prevent further erosion. In severe cases, it might be necessary to replace the entire retaining wall.
