Paver/Sand/Gravel Base Calculator

Why Your Pavers Are Sinking (And Why the Base is 90% of the Job)

The pavers are the easy part. The base is 90% of the job, and it is the part most DIYers rush or skip. A poorly compacted base is the number one reason pavers sink, rock, and heave. You cannot skip the compaction steps, and you cannot use the wrong material.

The base must be angular crushed rock (crusher run or 3/4" minus) that locks together when compacted. Smooth river rock or pea gravel rolls like marbles underfoot and will never compact. Lay the base in 2-inch lifts (layers) and compact each lift with a mechanical plate compactor. A hand tamper is fine for a small walkway, but for a patio or driveway, you need the plate compactor. Skip the compaction and your pavers will sink within a year.

The “Play Sand” Disaster: Why Fine Sand Ruins Paver Patios

Play sand and masonry sand are too fine for the bedding layer. They hold water, wash out, and do not provide a stable bed for the pavers. You need coarse, sharp concrete sand that drains well and provides a stable bed. The bedding sand must be screeded to a perfect 1-inch depth over the compacted base.

If you use the wrong sand, the pavers will settle unevenly, the joints will wash out, and you will be rebuilding the patio in a year or two. The extra cost of the right sand is cheap insurance against a rebuild. Call your quarry and ask for “concrete sand” or “bedding sand,” not “play sand.”

Edge Restraints: The Invisible Hero That Keeps Your Patio Together

Edge restraints are the invisible hero that keeps your patio from spreading apart over time. Without edge restraints, the pavers will spread outward as people walk on them, and within two years you will have a patio that looks like it was hit by a earthquake. Edge restraints must be rigid plastic or aluminum, spiked into the base with 10-inch landscape spikes every 12 inches.

Do not use cheap plastic edging meant for garden beds — it will not hold. Use rigid paver edge restraint designed for hardscapes, and use 10-inch spikes, not 8-inch spikes. The spikes must go through the restraint and into the compacted base, not just into the bedding sand. Skip the edge restraints and your patio will fail.

Polymeric Sand Hazing: How to Avoid the White Film Nightmare

Polymeric sand is the magic that locks your paver joints together and keeps weeds out. But if you do not install it correctly, you get a white hazy film on the paver surface that is nearly impossible to remove. The three rules: the joints must be bone dry before activation, the paver surface must be completely clean of dust before misting, and you mist gently until the joints are just damp, not flooded.

If you flood the joints, the polymers wash up onto the paver surface and create a white film that is nearly impossible to remove. Sweep the surface with a broom until it is completely clean, then mist gently with a fine spray until the joints are just damp. If you get hazing, you can try to remove it with a pressure washer on low, but prevention is the only real solution.

Pedestrian vs. Vehicular Base: Why Driveways Need 8+ Inches of Rock

A pedestrian patio needs a 4-inch base of compacted crushed rock. A driveway or hot tub pad needs an 8-inch base because vehicles and hot tubs are heavy and concentrate the load on a small area. A 4-inch base under a driveway will sink and crack under the weight of a car.

For a driveway, dig down 11 to 12 inches: 8 inches of compacted base rock, 1 inch of bedding sand, and 2 to 3 inches for the paver thickness. Compact the base in 2-inch lifts. If you are building a driveway, do not skimp on the base — it is the difference between a driveway that lasts 20 years and one that sinks and cracks in two years.