Rip Rap Calculator: How Much Rip Rap Do I Need?
The amount of rip rap you need depends on the volume of the area you need it to fill.
Rip rap is typically measured in tons, with different classes suited to various slope grades.
Use our rip rap calculator to determine the volume and convert it to tons.
A professional landscaping company can help measure for and install rip rap.
If you’re staring down an eroded shoreline or a slope that’s seen better days, calculating the right amount of rip rap you need can help your project stay grounded—literally. Whether you’re an experienced excavator or just want to double-check your contractor, our rip rap calculator can help you crunch the numbers without losing your footing—or your savings.
How Much Rip Rap Is Needed For Erosion Control?
You can’t calculate rip rap without considering the length, width, and depth of the space it will fill. Here’s a look at how many tons of rip rap you can expect to have installed based on your measurements.
| Length (Feet) | Width (Feet) | Depth (Feet) | Volume | Tons of Rip Rap Needed |
|---|---|---|---|---|
| 20 | 5 | 2 | 7.4 | 11.1 |
| 40 | 6 | 2 | 17.8 | 26.2 |
| 60 | 8 | 2 | 35.6 | 53.3 |
| 100 | 10 | 2 | 74.1 | 111.1 |
Calculating Rip Rap
To determine how many tons of rip rap you need, you’ll need to first calculate the volume of the rip rap needed in cubic yards, then convert cubic yards to tons. Start with the first calculation, then multiply the volume in cubic yards by 1.5 to determine the number of tons of rip rap you need.
Volume (cubic yards) = ((Length (feet) x Width (feet) x Depth (feet)) ÷ 27)
Tons of rip rap needed = Volume (cubic yards) x 1.5
Classes of Rip Rap
Rip rap comes in different size classes defined by the diameter of the stones. The chart below shows the different classes of rip rap based on size and what type of structure the rip rap is best used for.
| Class | Stone Diameter (Inches) | Best Used For |
|---|---|---|
| A | 2–6 | Small drainage ditches |
| B | 4–8 | Moderate slopes, small channels |
| C | 6–12 | Steeper slopes |
| D | 12–18 | Heavy-duty shoreline protection |
Who to Hire to Install Rip Rap
Rip rap can be installed by a number of professionals, so long as they have experience in erosion control and shoreline stabilization. Consider hiring the following experts to take on this not-so-small task:
Excavation Contractor
This type of specialist often handles grading, drainage, and shoreline work using heavy machinery to place and move large rocks.
Waterfront Contractor
If you live near a lake, river, or ocean, a waterfront contractor is your go-to for projects located on coasts or near shorelines. They often specialize in docks, seawalls, and rip rap installation.
Landscaping Company
Make sure to specify that you’re looking for a landscaping company with hardscaping experience since you’ll need experts who have a background in erosion control. The company you hire will need to be on the larger side, as you’ll require a whole crew and the right equipment to handle rip rap.
Civil or Environmental Engineering Firm
Although they may not be the ones installing your rip rap, a civil or environmental engineering firm can help design the rip rap placement, obtain the correct permits, and recommend trusted installers to bring their plans to life.
Rip rap serves as a protective layer of rock that stabilizes slopes and prevents erosion from waves and water flow. It’s made of large stones or boulders and can be found along shorelines, streambeds, or bridge foundations. Rip rap works by slowing down water velocity to prevent strong water forces from eroding surfaces.
The cost to install rip rap is about $20,000 on average, depending on what type of rock you use, how much of the rock you need, and the length and width of the shoreline, among other variants. The cost ranges from $10,000 to $30,000, but can increase to $120,000 if the project is extensive.
If you have a considerable amount of excess rip rap, you will need to hire a local landscape grader or a construction company that specializes in rip rap installation to remove it for you. Because rip rap consists of large stones, it requires proper equipment to haul away and dispose of properly. If you happen to have the necessary equipment, you can drop off your excess rip rap at a landfill or transfer station.
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