Polymeric Sand Calculator

Why Polymeric Sand Coverage Varies So Much

Bag labels quote polymeric sand coverage as a wide range — often 30 to 150 square feet per bag — because the sand only fills the joints. What matters is how much of the surface is joint, and that depends on two things: paver size and joint width. Small Holland pavers have far more joint per square foot than large slabs, and doubling the joint width roughly doubles the sand. The polymeric sand calculator works out the joint volume directly, so it gives one number for your patio instead of a range.

Polymeric Sand Coverage Chart

Figures assume joints filled 2-1/4 inches deep (1-3/4 inches for slabs, 1-1/2 inches for flagstone) and no waste. Add 10 percent for sweeping loss.

How the Polymeric Sand Calculator Works

1. Joint share of the surface

Each paver plus its joints forms a repeating module. For a 6 × 9 inch paver with 1/8 inch joints, the module is 6.125 × 9.125 inches, and the joint takes up 0.125 × (6 + 9) + 0.125² = 1.89 square inches of it — about 3.4 percent of the surface.

2. Joint volume

Multiply the joint share by the joint depth. At 2-1/4 inches deep, every square foot of patio has 0.034 × 2.25 ÷ 12 = 0.0063 cubic feet of joint to fill.

3. Pounds and bags of polymeric sand

Polymeric sand weighs about 100 lbs per cubic foot, so that is 0.63 lbs per sq ft. A 192 sq ft patio needs about 122 lbs, or 134 lbs with 10 percent extra — three 50 lb bags. Each bag covers about 79 sq ft.

Polymeric Sand Joint Width and Depth

Standard polymeric sand is made for narrow joints, typically from about 1/8 inch up to around 1/2 inch wide. For wider joints, such as flagstone or tumbled stone with 1 to 4 inch gaps, use a wide-joint polymeric sand, which has coarser aggregate and a stronger binder. Check the product label for its joint range.

Fill joints to about 1/8 inch below the top of the paver, or to the bottom of the chamfer on pavers with bevelled edges. The joint depth in the calculator is therefore the paver thickness minus 1/8 inch — 2-1/4 inches for standard 2-3/8 inch (60 mm) pavers. Polymeric sand needs a minimum joint depth, often around 1-1/2 inches, to bind properly.

How to Install Polymeric Sand

• Make sure the pavers and joints are completely dry before you start.
• Pour polymeric sand over the surface and sweep it into the joints.
• Run a plate compactor with a protective pad over the pavers to settle the sand, then top up and repeat until the joints stay full.
• Blow every grain of sand off the paver surface with a leaf blower; residue left on top will haze.
• Mist the surface with water as the label directs to activate the binder, and keep it dry and off-limits for the stated curing time.

Polymeric Sand Cost

Polymeric sand typically costs $25 to $45 per 50 lb bag, with wide-joint and premium products at the high end. For tight-jointed pavers that works out to about $0.40 to $0.75 per square foot; wide-jointed flagstone can cost over $1 per square foot. Buy a spare bag — running short halfway through is worse than having one left over, because polymeric sand should be activated in one session.

Related Sand Calculators

These tools use the same volume and density maths for neighbouring jobs:

• Paver sand calculator — the bedding sand under the pavers
• Paver base calculator — base gravel, bedding sand and pavers
• Sand calculator — any sand by area and depth
• Sand and gravel calculator — base gravel and sand together
• Masonry sand calculator — fine sand for regular joint filling
• Patio gravel calculator — patio bases

Joint filling practice follows segmental paving guidance from the Interlocking Concrete Pavement Institute; always follow the polymeric sand manufacturer's joint width, depth and curing instructions.

Polymeric Sand FAQ

How much polymeric sand do I need?

It depends on paver size and joint width. With 1/8 inch joints, a 50 lb bag covers about 59 sq ft of 4x8 Holland pavers or 79 sq ft of 6x9 pavers. A 12 by 16 ft patio of 6x9 pavers needs about three 50 lb bags.

How many square feet does a bag of polymeric sand cover?

Anywhere from about 30 to over 150 sq ft per 50 lb bag. Narrow joints between large pavers stretch a bag furthest; wide joints between small pavers or flagstone use it fastest.

How deep should polymeric sand be in the joints?

Fill the joints to about 1/8 inch below the top of the paver or to the bottom of the bevel. Most products need at least about 1-1/2 inches of joint depth to bind well.

Can polymeric sand be used for wide joints?

Standard polymeric sand is meant for joints up to around 1/2 inch. For flagstone and joints of 1 to 4 inches, use a wide-joint polymeric sand made for that purpose.

How much does polymeric sand cost?

Polymeric sand costs about $25 to $45 per 50 lb bag, or roughly $0.40 to $0.75 per square foot for tightly jointed pavers.