Base Rock for Missouri Lanes, Pads and Farm Drives

Tip a load out at the top of a gravel county road and the first surprise is usually the dust. Take a handful off the pile: a few pieces run close to an inch across, most are a good deal smaller, and a fine gray powder comes up with them and coats your glove. That powder is the whole point of base rock. On the cherty clay under most Ozark lanes, and on the tight claypan under the prairie ground up north, it is the fines that turn a loose heap of stone into a layer a loaded truck can cross without cutting it up.

Is this the same rock the quarry down the road calls Type 5?

Close enough that it is worth checking before you order. What ships from this page is Base Rock: 3/4 inch minus, a graded mix of crushed stone, gravel and binding fines, sold as a crushed aggregate blend. Missouri base material is specified by MoDOT Section 1007 as Type 1, Type 5 or Type 7. Type 1 and Type 5 are both 1 inch dense-graded mixes of crushed stone and fines, with Type 5 also capping the finest dust fraction, while Type 7 is a coarser 1-1/2 inch grade. Those are the designations quarries and county crews use when they write down what they want, not a certification carried here, so if a plan sheet or a road district calls for a particular type, hold it up against the grading above first.

One thing it is definitely not is clean rock. Around here clean rock means washed stone with the fines taken out, which is the opposite of what makes this material lock up.

How deep does base rock go under a garage pad on claypan?

Depth is a ground question before it is a load question. Under a shed or detached garage pad carrying cars and a mower, a compacted course of around four inches does the work on ground that drains. Where it stops draining, go thicker and build it in lifts of a few inches at a time, wetting each lift and running a plate over it, because one deep dump will stay soft in the middle no matter how long you roll the top of it.

Two Missouri situations are worth separating. On the flat northeastern prairies and the northern till plains, water perches on the clay subsoil and stands from late fall into spring, so shape the grade and give that water somewhere to leave before a yard of rock goes down. In the Ozarks the problem flips: chert and rock slow the digging, but once you are down to it the subgrade is firm, and the course can be thinner than a northern one doing the same job.

Can I leave it as the finished surface on a farm lane?

You can drive on it, and plenty of Missouri lanes are running on nothing else. It just will not stay pleasant. The fines that make it compact are the same fines that hang in the air behind a truck through a dry August, and that skin over into something greasy for a day or two after a March rain. Most people put a surfacing course over the compacted base once it has set up, which is where Driveway Gravel comes in, and keep the base where it belongs.

Why does it sink out of sight under a rock garden bed?

This is the most common wrong order in the catalogue. Somebody building a xeriscape or rock garden bed wants a firm layer under the decorative stone and reaches for base rock because it packs. Then the fines wick moisture up into the bed, weed seed finds the dust and germinates in it, and the decorative stone works its way down into the layer until the bed looks half buried. A rock bed wants fabric and a washed stone beneath it, or nothing at all.

What happens where a downspout dumps onto it?

Concentrated water does to a base course what a hose does to a sandcastle. Where a downspout discharges straight onto compacted base, the flow strips the fines out of the first few feet, leaves a nest of loose stone that rattles underfoot, and hollows out a pocket that grows a little every storm. Missouri summer storms arrive hard and short, which is exactly the pattern that does this. Put a splash area of washed 1 inch clean at the discharge point, or run the downspout past the pad entirely.

How many cubic yards does a 14 by 20 garage pad take?

Work it in volume and let the calculator handle the weight. A 14 by 20 foot pad at six inches of compacted base comes out at 14 x 20 x 6/12, which is 140 cubic feet, and 140 divided by 27 is 5.2 cubic yards. The splash area beside it, say four feet by six at four inches, is 24 x 4/12, or 8 cubic feet, a shade under 0.3 cubic yards. This site publishes about 3,000 lb per cubic yard for the crusher run and road base family, roughly 1.50 tons to the yard and approximate, so the pad comes out at 5.2 x 1.50, near 7.8 tons, and the splash area at a shade under half a ton.

Material ships by the ton, so run those cubic yards through the base rock calculator to turn volume into an order weight. The calculator adds a ten percent extra by default, and on a rough or rutted subgrade it is worth keeping, because the low spots swallow more than the tape measure suggests.

What has to be clear before the truck backs in?

Delivery is arranged at checkout from your ZIP code, and the truck needs a firm, reachable place to tip. That matters more in Missouri than the quantity does: a steep lane out of a hollow, a low-water crossing, or a soft spring shoulder can all decide where the pile ends up. Pick a quantity and a date on this page once you have your yardage, and if the only way in is narrow or steep, say so through the contact page before the load is booked, so the drop spot is agreed rather than discovered.