Blue Stone Sub Base (21A)

We stock blue stone sub base in 50 lb. bags.

Blue stone sub base comes in 50 lb. bags with 56 bags on a pallet. If you’re ordering a full pallet of material, we will bring a forklift to unload the product onto your driveway.

In addition to delivery, we can also provide installation services. If you’re interested in having our team install your blue stone sub base, please book a landscape appointment and select Draining & Grading Issues as the appointment type. If you are interested in having our landscape design team build out a patio, walkway, driveway or other hard surface, please book a Full Service landscape design appointment.

When installing blue stone sub base and other stone products:

• Measure the area where you intend to place your gravel. Then, use our coverage calculator to determine how much blue stone sub base you need.
• Use an edger to create a perimeter around the area you wish to fill.
• Use a hoe to remove the grass where you will place your landscaping stone.
• Dig the area as deep and wide as you wish to place your blue stone gravel. See the frequently asked questions section for recommended depths.
• Tamp down the blue stone gravel with a tamper or roller. This will create a strong base that won’t move much with weather and watering. Smooth it out with a rake and then rinse your rocks to remove dust and dirt and keep it looking fresh and clean.

How do I know how much gravel to use?

The typical common depths for base gravels like blue stone sub base are:

• Patios: 4 to 6”
• Garden paths: 2 to 4”
• Paver walkways: 4 to 6”
• Driveways: 10 to 12”

All of these recommended depths are based on the assumption that you are working with a good, solid soil base. To determine if you have a good, solid soil base take a piece of rebar and press it into the ground using your body weight. If it only goes into the ground up to 2”, the soil base is sufficient. If it goes into the soil more than that, you need to continue to remove the soft soil until you reach a solid base. Continue to test the soil base in this same manner until you’ve reached hard soil.

Use our coverage calculator to see how much material you need for your square footage based on the depth of your application.

What is the recommended material for a permeable driveway base?

If you are installing a permeable driveway, we recommend that you use 57 gravel for your entire base layer as it allows water to easily drain through the subbase. 21A will create too solid of a layer that will prevent water from running through the surface.

Does Blue Stone Sub Base (21A gravel) compact well?

Yes, Blue Stone Sub Base (21A gravel) compacts well. You can expect 25% compaction depending on the moisture and the thickness of the layer. We recommend compacting after layering in 2” of Blue Stone Sub Base (21A gravel).

What is Blue Stone Sub Base (21A gravel) used for?

Blue Stone Sub Base (21A gravel) is most commonly used as a base material in retaining walls, driveways, patios and walkways. It also helps make solid footings for small structures and can act as a base under sheds or hot tubs.

Can I use Blue Stone Sub Base (21A gravel) for my drainage project?

Blue Stone Sub Base (21A gravel) is not the best material for a drainage project as the fine components prevent water from moving freely. 57 gravel is a better drainage material.