This article is the second in a three-part series about gravel grids:
- “What are Gravel Grids?”
- “What are the Pros and Cons of Gravel Grids?” (this article)
- “How Do I Pick a Gravel Grid Product?”
In this article, we go in depth about the pros and cons of using gravel grids.
The Benefits of Using Gravel Grids (Pros)
In our research, many manufacturers made similar claims about gravel grids. We included some of these claims and a few observations of our own.
Gravel grids add structural support to gravel surfaces, preventing issues like gravel migration and rutting.
Typically gravel surfaces must be top-dressed with new gravel and/or regraded periodically. Gravel grids hold gravel in place, preventing the migration of the top layer of gravel laterally (sideways) as well as down into the gravel base or subgrade. Rutting is prevented as a result. These benefits lead to longer-lasting surfaces and lower maintenance costs.
Gravel grids can reduce the amount of gravel needed on a project and the depth of excavation required.
Gravel grids combined with gravel can have the same structural strength as a deep layer of gravel. For example, one manufacturer claimed that 1″ of gravel contained in their gravel grid system is equal in strength to a 3″-4″ of gravel layer. Other manufacturers made similar claims.
As a result, less gravel may be required to build the base and fill the grid when compared to a traditional gravel surface. Less gravel means less excavation, leading to saved time and money.
Gravel grids can create a permeable driving surface.
Permeable surfaces allow water to drain through and seep back into the water table rather than draining off the sides of the project area. Commercial gravel grids can even help control stormwater infiltration and create water storage.
Gravel grids can maximize the amount of driving surface on a property without running afoul of paving restrictions.
Some municipalities restrict how much impervious (non-draining) paving can be done on a property. Gravel grids can skirt this issue by providing permeable surfaces that are also drivable. This can eliminate the need for large, expensive drainage systems or retention ponds.
Some gravel grids meet accessibility standards.
The ADA defines an accessible surface as “stable, firm, and slip resistant.” Some brands have test data to demonstrate how their system meets this standard.
Gravel grids can give patios, walkways, and driveways a neat, uniform appearance.
Grids typically require clean crushed rock (gravel without fines). This results in a cleaner, more appealing look than a gravel surface built with minus crushed rock (gravel with fines).
Gravel grids can reduce driveway dust.
Because the cells are usually filled with a clean gravel, less fines may become airborne during dry weather.
Gravel grids may be more “green” than asphalt or concrete.
Some manufacturers claim that gravel grids are a greener alternative to asphalt and concrete, pointing to the use of recycled or recyclable plastics; the longevity of their materials; and the projected lifespan of the completed surfaces compared to typical gravel roads. The permeable nature of gravel grids also reduces the footprint of the paving surface. Additionally, some manufacturers claim that their systems naturally filter water before it passes back into the water table.
The Challenges of Using Gravel Grids (Cons)
Gravel grids require precise installation.
While some manufacturers claim that installing gravel grids is quick and easy, the reality is that the installation process takes time and attention to detail. Excerpts from the GeoPave and Gravelpave² installation guides are shown below to give insight into the installation process.
One Seattle-based landscaper who works with a rolled mat product said, “A lot more care goes into installing it.”
The basics of installation for each grid system are the same: the project area must be excavated, leveled, and compacted. Then most systems require a gravel base to be installed, leveled, and compacted. The gravel grid system is laid out on top of the gravel base and filled with rock.
Some systems require additional steps, including the following:
- Staking. Some gravel grid systems must be staked in place regardless of the grade (e.g., BaseCore, GroundGrid, EZ Roll, Gravelpave²). Most systems must be staked in place on steeper slopes.
- Clipping or stapling. Some gravel grid systems require panels to be stapled together (e.g., GroundGrid) or clipped together with special accessories (e.g., BaseCore, GeoPave).
- Cutting. Gravel grids may need to be cut to fit the shape of the project area using a saw or shears.
- Installing additional layers of material. Some gravel grid manufacturers recommend the installation of a geotextile layer between the subbase and gravel base or between the gravel base and gravel grid.
With all of these steps in mind, you can see how installing a gravel grid can be time-consuming and labor-intensive.
Most gravel grids require permeable rock products, which are typically more expensive per ton than minus rock products.
A typical gravel driveway is built with one or more layers of minus rock products—for example, 1¼” minus for the base layer and 5/8” minus for the top layer.
On the other hand, most grid systems are built with a base layer of clean gravel, ranging from ¼” clean to 1½” clean. The top layer, aka the infill, is usually a clean gravel ranging from 1/8” to 1½” clean.
Clean rock products are generally more expensive due to the processing and resources required to remove the fines. Some customers may also choose to use a decorative gravel for the infill (e.g., salt and pepper granite, marble chips, rainbow rock), which will be even more expensive than a construction-grade gravel.
Gravel grids can be expensive, especially for large projects.
Of the brands we surveyed, prices ranged as followed:
- $0.46–$2.52 per square foot for collapsible panel-style gravel grids
- $2.85–$4.95 per square foot for rolled mat-style gravel grids
- $1.81–$5.15 per square foot for paver tile-style gravel grids
Keep in mind that these prices don’t include the cost of accessories like clips, stakes, edging, and geotextiles. These prices also don’t include shipping or tax, potential labor costs, or potential equipment or tool rentals.
To give a better of idea of the true cost of each system, we created a chart that compares each brand’s cost per square foot with the preparation and materials required.
To get a more accurate picture of the total cost of each gravel grid system, it’s important to examine the installation guide of your chosen product to determine all of the materials and tools you will need. You can use our guide to estimate the volume of gravel you’ll need.
Gravel grids are low-maintenance—but not no-maintenance.
In order to hide the cell structure completely, an extra layer of gravel must be spread on top of the grid, a process known as top-dressing. This means that there will be some degree of loose gravel migrating on the surface that needs to be swept back in place and/or topped off regularly.
Although gravel grids prevent rutting and potholes, these issues can still occur. Cells may need to be topped off with gravel occasionally. In the case of potholes, sections of grid must be emptied and removed to address problems with the gravel base or subbase.
You will also need to clear debris like leaves and trash to preserve the permeability of the surface.
Lifting and buckling can occur when a product is pushed past its limits.
Gravel grids may lift out of place, buckle, or warp when a product is pushed past its limits. For example, a local dealer told us that his clients used a light-duty product but drove heavy equipment on it, resulting in the product lifting and becoming wavy.
Improper installation can cause similar issues.
Not all products have the data to back up their claims.
One thing became clear when conducting research for this article: robust products cost more money. There are many knockoff products on the market that are much cheaper than the competition. But these brands may lack installation guides, test data, and customer support. They may also have issues with material composition and construction.
Here are examples of concerning issues we found:
- VEVOR and Vodaland generics had no detailed installation guides or test data on their websites.
- Vodaland claimed on their website to have case studies to back up their product, but the case-studies link led to a blog.
- The GRAVALOCK website had many issues, including calling a mallet a “gum hammer,” using nonsensical phrases, and misspelling the customer service email multiple times. A customer rep responded to our phone call but gave us an email address that didn’t work.
The moral of the story: make sure the data backs up the claims.
This article does not represent an endorsem*nt of any brand and is meant for educational purposes only. There is a possibility of errors in the data. If you notice any errors, please send us a note through our contact form.
Check out other helpful articles on our blog:
- “Choosing a Topsoil or Soil Mix”
- “Clean v. Minus”
- “How Do I Make a Gravel Surface Wheelchair-Accessible?”
- “How Many Cubic Yards Do I Need?”
- “How to Find, Vet, and Hire a Contractor Who Can Work with Rock”
- “What Does a Cubic Yard Look Like?”
