After weighing the various options for an inexpensive yet attractive retaining wall, you’ve eliminated some of the options. The precast concrete block and waste concrete block retaining walls just won’t get the job done in your landscape. Therefore, you’ve settled on the boulder retaining wall. However, before you get started there’s one burning question remaining, how much does a boulder retaining wall cost?
What Is A Boulder Retaining Wall?
A boulder retaining wall is built by stacking boulders one on top of another with a generous setback to prevent over-topping of the retaining wall. Often the boulders will be mixed in with large sections of earth. This makes the ‘retaining wall’ look more like a planted hillside. The cost of creating this planted hillside can be much higher than just a boulder retaining wall. However, to keep things simple, let’s eliminate planting costs for now and look at the boulder retaining wall on its own.
Boulder Retaining Wall Cost Factors
How much a boulder retaining wall costs is based on a few factors. Like many other large projects, the size of the boulder retaining wall is always something to consider. However, there are more specific factors that play a role.
Retaining Wall Location And Access
First, you need to consider where the wall is being built and what the access is to the wall construction area when figuring out the boulder retaining wall cost. Do you have a septic system that needs to be avoided? Can you drive a 10 wheel or tri-axle dump all the way to the wall construction area? If not, you’ll need to factor in additional machine time to shuttle boulders from a dump site elsewhere on the property to the wall construction area. This can double or triple your machine time requirements and do the same to your budget.
Boulder Material Source
Next, where did the boulders come from? The source and distance of the boulders from where the retaining wall will be built is an important factor. Did you select them one by one at a landscape boulder field? Or did you get a truckload of boulders from a sand pit or rock yard? The latter is going to be your less expensive option, only eclipsed by the cheapest source which would be your very own site. However, even site sourced boulders can cost more in some cases. If you have 20 acres and the boulders are strewn about all over the place it’ll take time to collect the boulders, and whenever you’re talking about heavy equipment, time is money.
Boulder Installation Quality
For the next step, you need to consider how the boulders are being placed. Are they being placed with an excavator with a thumb? That is just picking up the boulders directly, scratching them up and placing them? Or are the boulders getting moved with nylon straps and being carefully placed to ensure the natural patina on the boulders remains? The least expensive way to build a boulder retaining wall is using the machine to move the boulders without regard to scratching the boulders.
How Much Does A Boulder Retaining Wall Cost?
It’s difficult to estimate a one size fits all price range for boulder retaining walls. Instead, we’ll breakdown the price into an inexpensive excavator way and a professional landscape design example. As you will see below, a boulder retaining wall can cost a few thousand dollars or tens of thousands of dollars depending on the method and size of your project.
Inexpensive Boulder Retaining Wall Cost
While we were working at a pool builder, we oversaw several boulder retaining wall projects. This involved the an excavation crew moving some boulders into place on the homeowner’s property. Depending on size, the excavation costs totaled between $2,000 – 2,500. Some of the homeowners had boulders on their property. Whereas others had to purchase a few boulders for a $1,000 load. Therefore, an inexpensive boulder retaining wall could cost between $2,000 – 4,000.
Professional Boulder Retaining Wall Cost
Nowadays, we spend more time in the landscape design industry. Choosing a landscape design firm is expensive, but if you’re adding many things to your backyard at once, they’re very much worth it. Building a boulder retaining wall with a landscape design firm guarantees more attention to detail and customization. However, the typical price of a boulder retaining wall will then far exceed that of an excavator-made one.
Each boulder will be hand-selected and carefully transported to your property. Then, each boulder is placed in a specific location and can even be rotated to the perfect angle. We’ve seen large professional boulder retaining walls cost anywhere from $50,000 – 100,000.
How To Calculate Your Own Boulder Retaining Wall Cost
To calculate boulder retaining wall cost, you can start with the boulders. You can expect to pay anywhere from $400 to $1000 per load for boulders from a sand pit. If you’re buying nicer boulders from a rock yard or boulder field and planning to use lift straps, you can easily 10x that cost, just for the materials.
An excavator and operator with helper and/or dump truck driver often costs around $1500 – $2000 per day. If you’re bucket setting the boulders (not using lift straps), you may be able to finish your wall in a day or two. When you have tough access and need to shuttle the boulders from the front yard, you’ll need to double the machine time expectation.
If you’re planning to set the boulders with nylon straps, expect machine costs and labor costs to be 5x or more than just setting them from the bucket. You’ll also likely be paying a design professional to oversee the boulder placement which adds even more expense. For the right project though, this can be the difference between a pile of boulders and a beautifully planted hillside.
How Much Does A Boulder Retaining Wall Cost Summary
How much a boulder retaining wall cost varies will depend on the above factors. Specifically the cost of labor where you live, the availability of boulders, and your taste when it comes to how the boulders should be set. You can spend as little as a few thousand dollars on boulder wall construction, or tens of thousands of dollars for an artistically placed landscape boulder arrangement. It is all up to you and your budget.