Driveway Gravel for Pennsylvania Lanes and Parking Pads

Up on the high plateau of the Northern Tier, a lane is usually a cut into a hillside with a ditch on the uphill side and a long grade running down to the township road. Rain and snowmelt come off those steep valley sides fast, and the water reaches the lane before it reaches the ditch. Driveway gravel is the running course on a lane like that. The first thing worth saying about it is that it is not the material most people have in mind when they order it.

Graded 3/4 inch, and the reason it is not 2A modified

What arrives is crushed stone at three quarters of an inch, supplied as a graded mix of sizes rather than one uniform stone. Mixed sizes matter, because the smaller pieces sit down into the gaps between the larger ones and a spread layer knits together under tires instead of rolling out of the way of them.

2A Modified is a different animal doing a different job. It is the dense-graded base, the stone with the fines left in, and it is meant to be compacted in lifts underneath a surface. Ask driveway gravel to be your structure and it will disappoint you. Ask modified stone to be your finished surface and you get a hard gray layer that sheds water but goes greasy in a thaw. The two are ordered together far more often than either is ordered alone.

Choose it when the lane already has something under it

This stone is the right order when a lane, a barn approach or a parking pad already has a compacted base in place and needs a fresh wearing course over the top. It is also right when an existing gravel drive has thinned, gone patchy in the wheel tracks, or lost stone into the ditch over a couple of wet springs and wants topping up rather than rebuilding.

Skip it when the ground under the lane has never been prepared. Stone spread straight onto soft plateau soil disappears into it within a season, and the deeper the layer the more of it there is to lose. Build the base first, then surface it.

Wall backfill, a pond edge and a gate entrance are not driveway gravel jobs

Three jobs come up constantly on a rural property, and none of the three takes driveway gravel.

Backfill behind a retaining wall. The drainage zone behind a wall wants clean stone with open voids, not a graded mix that packs. 2B Stone is the local name for that size and the correct order.

A pond or stream edge losing ground. Water attacking an edge moves any three-quarter stone it can reach. Armoring is RipRap, sold here by R-number, with the smaller sizes for ditches and the larger ones for banks.

A construction entrance at the gate. The point of an entrance pad is to shake mud off tires on big open rock, which means #4 Crushed Stone at 3/4 to 1-1/2 inches, not a surface course.

Two layers, and which one carries the truck

The structure is the compacted base. The surface course spreads load a little, sheds water and gives tires something to bite on, but it is not what keeps a loaded feed truck from sinking. On the plateau, frost reaches commonly 36 to 42 inches, set by each municipality, and no practical drive is built below that. What you are doing instead is keeping the layer drained so water is not sitting in it when it freezes, because saturated ground is what heaves and breaks a lane up.

That is why crown and ditch matter more than depth. A lane with a crown of an inch or so across each half of its width sends water sideways before it can run the length of the lane and take the stone with it. The calculator's own depth guide puts driveway work at about 4 inches, which is a sound figure for a fresh surface course over a prepared base. A top-up over existing stone is usually 2 to 3.

Tons for a 300 foot lane, and for the three jobs above

These are worked examples, not quoted jobs. Area in square feet, times depth in feet, divided by 27 gives cubic yards. Driveway gravel weighs about 2,800 lb per cubic yard on this site's published figures, which is 1.40 tons per yard.

The wall figure uses the clean stone weight of about 2,800 lb per yard and the entrance pad the larger-stone figure of about 2,900 lb per yard, both approximate. Run your own measurements through the gravel calculator before setting a quantity, since it carries the same densities and lets you add up to five separate areas.

Booking a delivery for a lane that dries out late

Set the quantity and the delivery date on this page. Delivery is worked out at checkout from your ZIP code, and the driver needs a firm spot to dump on with room to reverse out and clear height overhead. On a plateau lane that means waiting until the surface has dried after snowmelt, because a loaded truck on soft ground leaves ruts that then have to be filled with the stone you just bought.

If the approach is tight at the road end, or there is a weight-posted bridge on the route, raise it with Pennsylvania Rock Supply through Contact before you pick a date rather than on the morning.