Railroad Ballast for Virginia Ground That Will Not Drain

There is a corner of a lot or a stretch of a track on most properties in this state where the ground never quite recovers. On Piedmont clay it is the low end of a yard that stays greasy for a week after a storm. On the flat Coastal Plain, where water sits close to the surface anyway, it is anywhere the lot dips. In the valleys it is the spot where a spring seeps out below a bank. Each one has the same signature: something heavy keeps crossing ground that has no way of letting water go.

What a load of railroad ballast is, measured against what buyers expect

Railroad ballast here runs roughly 1 inch to 2.5 inches, large angular crushed stone, graded so the pieces interlock under load while water passes freely between them.

Read that specification carefully, because it describes two properties that most materials trade off against each other. A dense-graded base gets its strength from fines filling every space, which is exactly what stops water moving. Ballast gets its strength from shape instead: irregular faces wedged against irregular faces, with the voids left open. The stone resists movement under weight without ever closing up.

What it does not do is finish smooth. It is a foundation layer, and if the area above it has to be firm and closed, a finer compactable material goes over the top of it.

Patio sub-base, creek channel and fire pit standing, judged against that spec

The patio row is the one worth reading twice. Ballast under a patio is the drainage and bearing layer on ground that would otherwise stay saturated. It is never the bedding layer, and pavers set directly onto it will not stay level.

Freeze and thaw inland, storm water on the coast, clay that holds on

Conditions decide the depth more than the job does.

In the Shenandoah, Roanoke and New River valleys and up in the mountain counties, winters bring regular freeze and thaw, and any layer holding water in it heaves. An open stone foundation gives the water somewhere to be before it freezes. In the limestone valleys, watch where a concentrated discharge ends up, because runoff funneled into karst ground goes down into the rock rather than across it.

In Northern Virginia, where frost goes deeper than it does further south and the clay shrinks and swells with the seasons, the same logic applies with more depth behind it. Frost depth is set locality by locality here, so check yours rather than working from a statewide figure.

Along the Bay and the tidal rivers, storms and high tides put water over low ground from the outside as well as the inside. Ballast holds its position better than smaller stone when water runs across it, but armoring a bank against moving water is a different specification: that is a job for RipRap, sized against the flow rather than against load.

Ordering by the ton, and clearing the wet corner for the truck

Length in feet by width in feet, times depth in inches divided by 12, divided by 27 gives cubic yards. This site publishes roughly 2,900 lb per cubic yard for stone in the #4 and ballast family, about 1.45 tons per yard. Treat that figure as approximate.

• Example, a patio sub-base 14 ft by 18 ft at 6 inches: 252 sq ft x 0.5 = 126 cubic feet. 126 / 27 = 4.7 cubic yards, roughly 6.8 tons.
• Example, a dry creek bed 52 ft long averaging 4 ft wide at 8 inches: 208 sq ft x 0.667 = 138.7 cubic feet. 138.7 / 27 = 5.1 cubic yards, roughly 7.4 tons.
• Example, a fire pit surround, a ring 16 ft across with a 6 ft pit in the middle, at 4 inches. Area is 0.7854 x (256 minus 36) = 172.8 sq ft. 172.8 x 0.333 = 57.6 cubic feet. 57.6 / 27 = 2.1 cubic yards, roughly 3.1 tons.

Those are worked illustrations, not projects that were built. Add a little for the depth that presses into soft subgrade, which is real on wet ground and negligible on firm. Check your own figures in the stone calculator.

Before the load arrives, decide where it is going to sit and clear the route to it. The truck needs room to get in, tip with the body raised, and get out again, which means moving vehicles and trailers, cutting back low branches, and keeping the tipping point off the softest ground on the property. Mark anything shallow underground. Delivery is arranged at checkout from your ZIP code, so settle the access question before you choose a date.