Fill Dirt in Pennsylvania: Building a Grade Before Anything Else Goes On

Out on the Lake Erie plain the ground runs in low ridges of glacial till and old lake deposits, and between the ridges it is flat enough that water has nowhere obvious to go. Add a winter of lake effect snow melting into ground that is already dense underneath, and a yard can spend April as a pond. Fill dirt is what gets bought to change the shape of that ground: screened material with the large rocks, roots and debris taken out and very little organic matter in it, sold to build a grade rather than to grow anything.

What a load of fill dirt looks like next to a load of topsoil

Side by side they are easy to tell apart. Topsoil is dark, loose, smells of earth and breaks up in the hand. Fill dirt is paler and heavier, more mineral than organic, and a handful squeezed damp holds together as a lump instead of crumbling.

That difference is not cosmetic. The organic matter in topsoil is what plants live on, and it is also what rots away over the following years, taking the grade down with it. Fill dirt has almost nothing left in it to decompose, so once it is compacted the level you built is the level you keep. It is also dense to handle: this site's calculator pages put dry fill at about 2,400 lb per cubic yard and wet fill at up to 3,000 lb, which is worth knowing before anyone plans to wheelbarrow it far.

Raising a flat lake plain yard that drains nowhere

The job on flat ground over dense till is almost always the same: take a low area that collects water and rebuild it so water leaves in a direction you chose. That means thinking about where it goes next rather than just filling the hole. A low corner raised without a fall simply moves the puddle to the new low point, usually the neighbor's side or the base of the house wall. Set the finished contour first, work out the fall, and fill to that.

Snow and soft ground last into spring on this plain, and dirt placed on saturated ground will not compact. Wait until the ground is thawed and drained, and finish before the cold returns.

Three jobs where fill dirt is the bottom half rather than the answer

Take three hypothetical projects on one property.

A hot tub pad. Fill dirt brings the area up to a level, compacted platform. What the tub sits on is not fill dirt, it is a compacted base of 2A Modified or a slab designed for the load.

A side yard dog run. Fill dirt raises a wet strip out of the water, then it gets capped. The surface is a separate order, and for a dog run most people want a free-draining cover rather than bare soil.

A turnaround or parking pad. Fill dirt makes the subgrade, shaped and compacted, and then the structural layer goes on top of it. A vehicle pad built straight onto fill will rut in the first wet spell.

In all three, fill dirt is what gets the level right. Something else carries the load.

Where it is the wrong material outright

Three more, where ordering fill dirt wastes the load.

Anything that has to grow. Lawns, beds, seeding a ditch shoulder. Nothing worth planting in will thrive in low organic mineral soil. Those are Top Soil and Garden Soil orders.

The bottom of a drainage trench. Fill dirt holds water and packs tight, which is the opposite of what a trench needs. That is Drain Rock.

A final surface anyone walks on. Bare compacted fill turns to mud with the first rain. It always needs a cap, whether that is soil and seed, stone, or mulch.

Building a grade in lifts before the snow returns

Fill dirt only does its job when it is placed in thin layers and compacted as it goes. Strip the sod and any soft organic material off first, because building on top of turf leaves a layer that will rot and settle. Then place the fill in lifts of six to eight inches, compact each one before the next goes down, and keep the surface shaped so rain runs off the work overnight rather than into it.

A single deep dump of dirt, graded flat and left, looks the same on the day and settles for years. On a plain where the ground below is already dense and slow draining, a poorly compacted fill holds water inside itself, and then the frost gets hold of it. Allow for that settlement when ordering, because the tonnage you need is for a compacted result rather than a loose one.

Tons for an 18 by 22 turnaround and a 10 foot tub pad

Hypothetical examples. Square feet times depth in feet, divided by 27 for cubic yards, converted at the dry fill figure published on this site's calculator pages, about 2,400 lb per cubic yard or 1.20 tons per yard. Wet material runs heavier, up to about 3,000 lb per yard, so a load caught in the rain weighs more for the same volume.

An irregular low spot is the hard one to measure. Split it into rectangles and triangles, work out an average depth for each by probing at several points rather than measuring the deepest, and add the results. A triangle is half the base times the height. The dirt calculator will run your own figures if you want to check the arithmetic.

What follows the fill: soil, stone or mulch

Fill dirt is never the last thing on site. Over a lawn area, cap it with four to six inches of screened topsoil, then seed. Over a pad or a drive, the compacted stone base goes on next. Over a planting area, topsoil or garden soil, then Shredded Mulch once the planting is done.

Order the cap at the same time as the fill if you can, because two deliveries to the same drop spot is two sets of access arrangements. Choose the quantity and a delivery date on this page. Delivery is arranged at checkout by ZIP code, and the truck needs firm ground to tip on with room to pull clear. Flat, wet plain ground turns soft quickly, so pick the drop spot carefully and flag anything tight through Contact before booking.