How Much Sand Do I Need Under Pavers?

You need about one inch of bedding sand under pavers, screeded level, and no more. A 20 by 10 foot patio at that depth takes 0.68 cubic yards, roughly 0.92 tons. Going deeper is the single most common way a paver patio fails, and it fails slowly enough that nobody connects it back to the sand.

Why sand under pavers should be one inch, and why more is worse

The bedding layer has one job: to let each paver settle to a consistent level during compaction. It is a setting bed, not a structural layer, and it is the thinnest part of the build for a reason.

Sand deeper than about an inch keeps consolidating under load long after you finish. The pavers move with it, and the result is ruts in the wheel tracks of a driveway, lippage where one paver stands proud of its neighbor, and a surface that has to come up and be relaid.

What each depth costs

On that same 20 by 10 patio, with a 10% allowance included:

• 1 inch: 0.68 cubic yards, 0.92 tons, about $32.
• 1.5 inches: 1.02 cubic yards, 1.38 tons, about $48.
• 2 inches: 1.36 cubic yards, 1.83 tons, about $64.
• 3 inches: 2.04 cubic yards, 2.75 tons, about $96.

So the mistake is cheap to make and expensive to fix. Doubling the depth costs $32 extra on the way in and a relaid patio on the way out.

The quantity scales cleanly with area at a fixed depth, which makes it easy to size any other job from these numbers. Double the patio to 400 square feet and you need 1.36 cubic yards at one inch. A 20 by 20 driveway apron is 1.36 as well, because area is area. Only the depth changes the ratio, and the depth should not be changing.

Bagged or bulk

Dry sand runs about 100 pounds per cubic foot, so a 50 pound bag holds about half a cubic foot. The 20 by 10 patio needs 18.4 cubic feet, so that is roughly 37 bags, which is most of a pallet and a long afternoon of lifting. Bulk delivery is cheaper per yard and far easier to screed from, and the crossover for most people sits somewhere near a third of a yard. Bags make sense for a small landing or for topping up; anything patio-sized is a bulk order.

Getting the one inch right

Knowing the volume is only half of it. The inch has to be an inch across the whole area, and that is done with screed rails rather than by eye.

• Lay two lengths of 1 inch outside diameter pipe or square tube on the compacted base, parallel, a little narrower than your straightedge.
• Fill between them with sand and pull the straightedge along the rails to strike it level. The rails set the depth for you.
• Lift the rails, fill the two grooves they leave, and move on to the next bay.

Do not compact the bedding sand

This is counterintuitive and it matters. The base underneath gets compacted thoroughly, in layers. The bedding sand does not. You screed it loose, lay the pavers straight onto it without walking on it, and compact once at the end with a plate compactor running over the pavers themselves. That final pass is what beds each unit to a consistent level. Compacting the sand first removes exactly the give the process depends on. The industry guidance is explicit about it: CMHA’s Construction of Interlocking Concrete Pavements calls for the bedding to be screeded to an uncompacted nominal one inch.

Joint sand is a separate quantity

The sand that goes between the pavers after laying is a different material and a different order. It is swept into the joints, compacted in with the same final pass, and topped up until the joints stop taking any more.

Volume depends entirely on joint width and paver thickness, so it does not scale off the bedding figure at all. It is usually a small fraction of the bedding order, which is why it gets forgotten until the day it is needed. Buy it with everything else rather than making a second trip.

Which sand, because the wrong one fails too

Material matters as much as depth here.

• Concrete or sharp sand is what you want. The grains are angular, so they interlock and hold a screed under load.
• Soft building sand is the wrong choice. Rounded grains, holds water, does not lock up, and it is the reason a patio that was flat in spring is not flat by fall.
• Polymeric sand goes in the joints after laying, not underneath. It is a separate and much smaller quantity.

Weight moves with the weather

Sand is sold by the ton and used by the cubic yard, and the conversion is not fixed.

A cubic yard is 1.35 tons dry, 1.49 damp and 1.62 wet, so a rainy week adds a fifth to the weight of the same volume. You are charged by weight while the patio consumes volume, which is worth knowing before a large order.

What goes underneath

The sand is the thin layer at the top of a build that is mostly aggregate. A patio wants roughly 4 inches of compacted base, a driveway 6 to 8, and that is what carries the load.

The base also has to run past the finished edge of the paving, not stop level with it, so the outermost pavers are still sitting on something. Along with an edge restraint pinned into that overhang, this is what stops the perimeter units drifting outward and letting the bedding sand escape from the sides. A patio that spreads at the edges is losing its sand sideways, and no amount of extra depth in the middle prevents it.

The gravel calculator works out that base layer, and the concrete calculator covers anything being poured rather than laid. For the bedding sand itself, the sand calculator gives you cubic yards and tons from the same measurements so you can order in whichever unit your supplier quotes.

The paver calculator works the bedding sand out alongside the rest of the patio: the pavers, the compacted base under them and the edge restraint round the outside, which is the order you actually place rather than one line of it.

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