What Do You Need to Build a Retaining Wall
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What Do You Need to Build a Retaining Wall

Many people prefer to invest some money into landscaping projects around their house when buying a property. If your house is located on hilly terrain, then you may have considered placing a retaining wall to provide an unique look to your property and avoid soil erosion. Retaining walls can be a great addition to the landscape around your home if done right. In addition to that, these walls can be a practical solution to some problems a hilly terrain may have. With proper planning and installation, retaining walls can increase the usable area around your home, create an unique look to the property and protect the terrain from eroding.

Any construction project requires a lot of planning and precise calculations to make sure that the builders have all the necessary information to complete the project in an efficient and timely manner. Retaining wall projects are not an exception. Building a retaining wall may look like a simple project, but it requires a great deal of planning involving professional engineers and designers. Retaining walls have to withhold the pressure from the soil, which may be quite heavy especially when the soil is wet. If the wall is not planned out to withhold the pressure the soil may put on it, then the wall may simply collapse. In addition to that, a retaining wall will interfere with the natural water flow through the soil, which may lead to floods in some areas. Professional engineers and designers will be able to calculate the amount of concrete and other material needed as well as ensure that the project is structurally sound.

Because of the complexity of the task, the project that includes building a retaining wall may become quite costly. The budget for such a project usually includes wages for professional engineers and construction workers, cost of materials, and cost of construction permits. On average, a homeowner should expect to spend around $20 – $50 per square foot of the wall. Usually, the wall requires the same amount of concrete per square foot regardless of other factors. On the other hand, the factors such as the slope of the hill, type of ground, and length of the wall will determine the complexity of the project. As a rule of thumb, the more complex the project is, the more the homeowner will have to pay in wages. Every single expense is formed based on certain characteristics, so it is important to understand how exactly a homeowner can estimate the price for each expense.

Concrete Expense

Retaining walls can be built using different materials, but the most used material is concrete. For the sake of simplicity, we can assume that we are building a retaining wall out of concrete. If you choose to build your wall using something other than concrete, you simply need to adjust the price to approximate the cost of using another material.

A concrete retaining wall usually looks like a “T” upside down. It has a base that is buried in the ground. This base allows the wall to withhold the soil pressure and stay in place for decades. The following metrics must be estimated to calculate the amount of concrete needed:

  • Wall Height – Determined by the Project.
  • Wall Length – Determined by the Project.
  • Wall Width = Minimum 12 in.
  • Base Length = ½ of Wall Height.
  • Base Width = The larger of ⅛ of Wall Height and 12 in.

Looking at these metrics, it is clear that the amount of concrete required can be calculated using Wall Height and Wall Length. To calculate the amount of concrete needed, the following formulas can be used:

When you calculate the amount of concrete needed, you have to make sure that you use the same measuring units throughout the calculations. This means that if your measurements are calculated in different units, you may have to convert them before estimating the amount of concrete needed. The final result will yield the volume of concrete needed to complete the retaining wall. When you know the volume, you estimate the cost using the price of concrete.

Wage Expense

If you are planning to build a retaining wall, you may have to hire some professionals to design the project, prepare the area and build the wall. The total wage expense will depend on the length of the wall and the complexity of the project. Generally, a homeowner should expect to pay $50 – $75 per hour of work for a contractor and $100 – $200 per hour of work for a professional engineer. The number of hours needed to design and complete the project ultimately depends on the length of the wall and the type of surrounding area. A homeowner should expect to spend around $6 – $15 per square foot of retaining wall on wages alone.

The easiest way to estimate how much you may have to spend on wages is to talk to landscaping contractors who have experience building retaining walls. They can estimate the total cost of your project as well as provide a price breakdown including the cost of necessary materials and wage expenses.

Permit Expense

Retaining wall interferes with the natural flow of water in the soil. This disruption may lead to flooding in places that are not expected to flood. If a retaining wall is not installed properly, then it may flood neighboring houses. Because of such an issue, retaining walls tend to be regulated by the cities, so you might have to purchase necessary permits before building one. The cost of permits depends on the region and the average price ranges from $150 to $1,500 with the maximum cost reaching $6,000. Permit cost is a relatively small expense that usually takes up to 2% of the total cost of the project.

Final Estimates

All the inputs discussed above vary either with the complexity of the project or with the size of the wall. Because of that, instead of trying to calculate various costs, it may be more insightful to see the total cost of building a retaining wall. Luckily, many contractors are happy to supervise the whole project at a fixed cost for the client. A homeowner in the United States may expect to spend $20 to $50 per square foot to build the wall. The more difficult the project is, the higher the price per square foot will be.

A homeowner may consider saving money and working on the retaining wall themselves, but in most cases, this project requires a certain expertise in landscaping. If you do not have any experience with landscaping, you should not attempt to complete the project by yourself because it may lead to waste of materials and serious damage to the surrounding area. Make sure to discuss the project with professional contractors before choosing to proceed with it.

Photo by Mike Enerio on Unsplash

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