Mason Sand for Paver Bedding, Mortar and Play Surfaces

The ground under most patio work in this state changes size with the calendar. Expansive clay across the Coast Range valleys, the flood basins and many Southern California hills takes water through a handful of winter storms and swells, then shrinks and cracks apart by late summer. Sand cannot stop any of that. What it can do is give the layer above a true, even seat, so the surface you set stays flat while the ground below goes about its seasonal business.

What washing removes from mason sand, and why that matters here

The specification is short. The grain is ultra-fine and consistent in size, and the material is washed to take out clay, silt and organic matter. Those two properties are the whole product.

The consistency is why it screeds cleanly to a set thickness and does not settle unevenly under a paver. The washing is why it behaves the same in wet and dry weather. Unwashed sand carries the clay fraction that swells, holds water and turns greasy in a winter storm, and in a mortar mix that same clay content interferes with the bond. Screen out the fine material and the sand stops responding to the season. Its stated role is finish work and recreation rather than structure, which is the single most useful thing to know before ordering: sand beds a surface, it never carries it.

Hot tub pad, dog run and turnaround: what each job needs beneath

The pattern across the table is the same. On anything that carries weight, the sand is the last thin layer and a compacted base does the structural work. The one place it is the finished surface is a play or recreation area, where softness underfoot is the point.

Bedding depth under pavers, and what happens when it grows

A setting bed is meant to be thin and even, screeded to a consistent thickness and left uncompacted so the pavers bed into it when they are vibrated down. Thin is the operative word. When a bed gets deep, usually because someone is using sand to correct a base that was never leveled properly, the pavers begin to ride on a soft layer. Wheel loads and foot traffic then push the sand sideways, ruts appear along the lines people walk, and the joints open up. The fix is always in the base below, which is graded, compacted and sloped to shed water before any sand is spread.

Joint sand is a separate step. Sweeping fine sand into the joints after the pavers are down locks the units against each other, and topping the joints up after the first wet season is normal maintenance rather than a sign of a problem.

Shrink-swell clay, hardpan and blowing sand

Where clay is the subgrade, everything depends on water never sitting under the paving. A base that drains and a surface that sheds are what keep the clay from cycling through wet and dry underneath. Across parts of the Central Valley, a cemented hardpan a few feet down stops water moving deeper, so a patio built in a low spot can sit in a shallow pond after an atmospheric river. Set the finished level above the ground around it and give the water a route away.

In the desert and the high desert, the problem reverses. Loose sand left as an open surface blows in strong winds and scours during the short, intense storms that come through, so a play area or dog run there does better contained by an edge, kept out of a wash, and set below the level of the ground rather than proud of it.

Working out an order for a side yard with a narrow gate

Two quick examples. A hot tub pad of pavers 8 feet by 8 feet is 64 square feet; a 1 inch setting bed is 64 x 0.083, or 5.3 cubic feet, which divided by 27 is 0.2 of a cubic yard, with a little more again for joint sand. A side-yard dog run 32 feet by 9 feet is 288 square feet, and a 2 inch loose surface layer is 288 x 0.167, or 48 cubic feet, which is 1.8 cubic yards. This site publishes about 2,700 lb per cubic yard for mason and washed sand, roughly 1.35 tons per yard, so the setting bed is approximately 0.3 of a ton and the dog run layer about 2.4 tons.

Odd shapes are easier if you cut them into rectangles and add the pieces, and the paver base calculator will hold several areas at once so you are not doing it on paper. Mason Sand is ordered by the ton, with quantity and a delivery date chosen on this page and delivery arranged at checkout from your ZIP code.

Delivery day is where side yards cause trouble. Sand has to be tipped somewhere firm and reachable, and if the gate is 36 inches wide it is going to be wheelbarrowed through, so put the pile on the side with the shortest route and cover it if rain is forecast. Wet sand is heavy and sticky to shift. Check the delivery notes for access requirements before you pick a date.