Paver Base Calculator for Massachusetts Patios and Walks

The rectangle marked out on the lawn in front of you is not the area to type into this paver base calculator. The base has to run past it, and how far down it goes depends on what the shovel hits in the first six inches.

Paver base depth for a walk, a patio on till, and a parking apron

Start with depth, because it is the figure that decides everything after it.

Dense lower till sits under most of Greater Boston, the Worcester plateau and the hilltowns, and it holds snowmelt near the surface. That is the case for the upper end of each band and for fabric under the stone, which keeps the base from working down into a wet subgrade over a few seasons. Silty lake-bed ground on the Pioneer Valley floor behaves the same way. Outwash sand on the Cape, the Islands and around Plymouth and Carver drains fast, so the base there is carrying load rather than fighting water.

Six inches of base past every open edge before you measure

Here is the part that catches people out. Measure the paved footprint, then add six inches of base beyond each edge that is not against a wall or a house. That overhang is what the edge restraint sits on, and edge restraint pinned into lawn soil instead of compacted base is the reason patios creep outward.

So for an 18 by 10 ft patio tight against the house on one long side, the base rectangle is 19 by 10.5 ft, which is 199.5 sq ft rather than 180.

Then the tool itself: rectangle, circle or multiple areas up to five, length and width in feet or a diameter, depth in inches anywhere from 0.25 to 24, the material select, and the ten percent tick for compaction and spillage, on by default. Results come back as cubic yards, tons and cubic feet, and can be emailed.

Digging depth: base, one inch of bedding, and the paver itself

Excavation is a separate sum from the tonnage, and worth doing before the digging starts:

Excavation depth = base depth + 1 in bedding + paver thickness - the reveal you want above grade.

For a five-inch base under a standard 2 3/8 inch paver, that is 5 + 1 + 2.375 = 8.375 inches, call it 8.5 below the finished surface height, less whatever reveal you want. Mark it on a stake and check as you go. Overdigging means paying to move soil out and then paying for stone to put the level back.

An 18 by 10 patio against the house and a 26-foot side walk

Two hypothetical jobs on one order, entered as two areas.

The patio base at 199.5 sq ft and five compacted inches:

• 199.5 x 5 / 12 = 83.13 cu ft
• 83.13 / 27 = 3.08 cu yd
• 3.08 x 1.50 = 4.62 tons

A three-foot walk running 26 ft to the side door, with the overhang on both sides, is a base 4 by 27 ft, 108 sq ft, at four inches:

• 108 x 4 / 12 = 36 cu ft
• 36 / 27 = 1.33 cu yd
• 1.33 x 1.50 = 2.00 tons

Together: 119.13 cu ft, 4.41 cu yd, 6.62 tons. With the ten percent ticked, 4.85 cu yd and 7.28 tons. Order seven and a half and place it in two-inch lifts, misting each lift before the compactor goes over it, with a 2 to 3 percent fall away from the house built into the base rather than into the sand.

Three thousand pounds a yard, and the lawn it is landing on

The tool applies this site's published figure for crusher run and road base, roughly 3,000 lb per cubic yard, about 1.50 tons per cubic yard. That is the heaviest of the common base materials on the site, because the fines fill the voids between the pieces and make the layer dense enough to stay where it is put.

Seven tons is under five cubic yards, which is a smaller pile than the tonnage suggests. It is still seven tons sitting somewhere, and a pile left on turf for two weeks leaves a dead rectangle that has to be repaired afterwards. Schedule the drop for after the excavation, not before, and put it on the drive or on boards.

Rounding up on a patio you cannot reopen in November

Round up to the next half ton, and hold the remainder back rather than spreading it.

A shallow patch in a base does not announce itself. It shows up two winters later as one paver rocking under a chair leg, by which time the surface has to come up to fix it. The material to be generous with is the base; the one to be exact about is the bedding sand above it, which stays at one inch and is sized in the paver sand calculator.

Two neighboring tools, so you land on the right one. Use this page whenever the base has to run past the pavers. Use the crusher run calculator when you are measuring a lane, pad or turnaround with no edge restraint, where the base area and the surface area are the same rectangle, and the rest of the calculators cover the other layers of the job.

When the number is settled, open Crusher Run or Processed Gravel, set the quantity and a delivery date, and check out. Delivery is arranged at checkout by ZIP code, so check the delivery ZIP before you dig and leave the truck clear access to the drop.

Common questions

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