#4 Crushed Stone: Coarse Rock for Soft Missouri Ground

The decision behind most orders of this size is not really about stone. It is about a spot that will not hold: the back corner of a yard on northern claypan where water perches all winter, the low end of a field entrance that ruts every spring, the strip under a downspout that has been washing out since the house was built. Somebody has already tried a few inches of the usual gravel there and watched it disappear. What follows is whether #4 crushed stone fixes it, and where it does not.

Do I need 3/4 to 1-1/2 inch stone, or a smaller washed grade?

The grading is #4, which puts the pieces at roughly 3/4 to 1-1/2 inches, all angular, with no fines in the mix. The voids between pieces are large enough that water moves through fast and that soft ground cannot swallow the layer whole, because each stone is too big to be pushed aside individually.

Go smaller, to a 3/4 inch or 1 inch washed grade, when the job is a trench, a pipe bed, or any drainage run where the stone needs to pack neatly around something. Those grades are easier to shovel and kinder to walk on. Stay at #4 when the ground itself is the problem: saturated claypan, a wet approach that has rutted, or a slope where runoff is cutting. The whole reason for the size is that it does not move when smaller stone would.

What happens when #4 crushed stone goes under a shed pad?

It becomes the bridging lift, which is a different job from a base. Lay separation fabric over the shaped subgrade, tip this stone on it, level it and track over it with a machine to seat the pieces. What you end up with is a stable platform sitting on top of the soft ground rather than sinking into it, with fabric stopping the clay working up between the stones.

That platform is not the pad. Above it goes a fines-bound course such as Base Rock, compacted in lifts, and then whatever surface the shed sits on. Skipping the upper layer leaves you standing on loose rock that rolls underfoot and will not take a load evenly.

On cherty Ozark ground the bridging lift is often unnecessary. Dig down past the chert and the bottom is already firm, so the money is better spent on drainage than on depth.

Will a rock garden bed of 3/4 to 1-1/2 inch stone stay looking right?

For a xeriscape or rock garden bed, this size holds its appearance better than most people expect, with two conditions. It needs fabric under it, or the bed will sink into the soil over a couple of wet seasons and read as mud with stone in it. And it needs an edge, particularly on a slope, because angular stone creeps far less than rounded stone but it still travels when a mower or a storm gets at it.

Three inches is plenty of depth for a bed. What you will not get is a soft, tidy look: the pieces are big, sharp and irregular, so the effect is rugged rather than neat. If the bed is meant to look considered, rounded River Rock gives you a smoother read at a similar size.

Can it take the hit where a downspout dumps a roof's worth of water?

Yes, and this is one of the jobs it handles well. A Missouri summer storm can put an inch through a roof in twenty minutes, which is a surprising volume arriving at one corner of the house. Fine gravel in that spot scatters. Soil gullies.

Build the splash area as a shallow dished apron, fabric down first, four inches of this stone over it, running away from the foundation on a fall rather than sitting level against it. The size absorbs the impact and the voids take the volume. What it will not do on its own is solve a wet basement: the water still has to go somewhere once it is through the stone, and on claypan that usually means a line to daylight.

How many tons for a 12 by 16 pad and a splash apron?

Two hypothetical examples, worked through.

A shed pad 12 by 16 feet with a six inch bridging lift: 12 x 16 is 192 square feet, and six inches is half a foot, so 192 x 0.5 gives 96 cubic feet. Divide by 27 and that is 3.56 cubic yards. This site publishes about 2,900 lb per cubic yard for the #4 and ballast family, roughly 1.45 tons per yard, so 3.56 x 1.45 works out at about 5.2 tons.

A downspout splash apron 6 feet by 3 feet at four inches: 18 square feet x 0.333 feet is 6 cubic feet, which is 0.22 cubic yards, or about a third of a ton. Small orders like that are usually worth combining with something else on the same delivery.

A rock garden bed 20 by 8 feet at three inches is 160 square feet x 0.25, so 40 cubic feet, 1.48 cubic yards, and about 2.1 tons.

Run your own figures through the stone calculator, which carries depth guides and a five percent allowance for uneven ground that is on by default. Spreading is a machine job more often than not: a bucket or a skid steer moves it quickly, and while a wheelbarrow and a fork will handle a small apron, a five ton pad by hand is a long weekend.

Where the pile should land if the work is behind the house

Think about the drop before you think about the date. Coarse stone is heavy to move twice, so aim for a spot as close to the work as a loaded truck can safely get and still turn around, on ground firm enough to hold it after rain.

Delivery is arranged at checkout from your ZIP code, and the truck needs clear access to somewhere it can tip. If the only route to the back of the property crosses a soft yard, or the gate is tighter than it looks, raise it through the contact page first and agree a drop spot rather than finding out on the day. When the quantity looks right, pick an amount and a delivery date here on the product page.