Quarry Process (QP) Stone: What It Is, Weight and Tons

Quarry process, usually shortened to QP, is the name many yards in New Jersey, New York, Connecticut and eastern Pennsylvania use for crushed stone that still has all of its fines in it. A typical load runs from about 3/4 inch pieces down to rock dust. Because the small particles fill the gaps between the larger ones, QP packs into a hard, fairly smooth layer when it is wetted and compacted, which is why it is the default base for driveways, walkways, patios, shed pads and the stone layer under asphalt in that part of the country. A loose cubic yard weighs roughly 1.4 to 1.6 tons. This guide explains what QP is, how it lines up with crusher run, DGA and other regional names, where it works and where it does not, and how many tons to order.

QP tonnage calculator →

What quarry process stone is

At a quarry, blasted rock goes through crushers and then over screens that sort it by size. Clean stones such as #57 are what stays on the screens after the small particles are washed or shaken out. Quarry process is close to the opposite: the crushed rock is kept as a blend from the top size down to dust, so nothing that makes it pack is removed. You will hear it called “QP,” “quarry process stone,” “QP gravel” or “3/4 QP.”

Most QP sold for home projects tops out around 3/4 inch. Some yards also sell a coarser version with pieces up to about 1 1/2 inches for thicker or heavier-duty bases. The rock itself depends on the local quarry. In the New Jersey and New York area it is often a dark trap rock or a gray granite or gneiss; elsewhere it may be limestone. The color of the finished surface follows the rock, so look at a pile or a sample before you order a whole driveway.

QP vs crusher run, DGA, Item 4 and 2A

These names mostly describe the same kind of material, a dense crushed stone blend with fines, sold under whatever name is common locally or under a state highway spec. The exact gradation is set by the quarry or the spec it is made to, so two products with the same name can differ a little.

Name you may hear	Where it is common	What it usually means
QP / quarry process	NJ, NY metro, CT, eastern PA	Crushed stone about 3/4 inch to dust
DGA / DGABC	NJ (state spec name), KY and others	Dense-graded aggregate (base course) made to a spec; see our DGA guide
Crusher run / crush and run	Mid-Atlantic and Southeast	Crushed stone with fines; see our crusher run driveway guide
Item 4	New York	Subbase stone named after the state highway item; see our Item 4 guide
2A modified	Pennsylvania	PennDOT-style dense base; see our 2A modified guide
21A, CA6, road base	VA, IL, western states	Regional names for similar dense base blends

If plans or a town permit call for a specific state spec, ask the yard whether its QP is certified to that spec. For a home driveway or patio, the practical question is simpler: does the material have enough fines to lock together when compacted? Grab a handful. Good QP has visible dust and small chips mixed through the larger stones, and it holds together a little when damp.

Virgin QP vs recycled concrete QP

Many yards also sell a recycled version made from crushed concrete, sometimes listed as RCA (recycled concrete aggregate) or “recycled QP.” It compacts much like stone QP and often costs less. The tradeoffs:

Debris. Recycled material can carry bits of rebar, brick or asphalt. Reputable yards screen most of it out, but look at the pile.
Runoff. Fresh crushed concrete can leach alkaline water at first, so keep it away from ponds, streams and plantings you care about.
Weight. Crushed concrete is usually a little lighter per yard than trap rock QP. Our crushed concrete weight guide has the numbers.

For a base under asphalt or pavers, either can work if it is compacted well. Our post on recycled concrete under asphalt goes deeper.

What QP is used for

Gravel driveways. A compacted QP top layer gives a firm, fairly smooth surface that plows better than loose stone. On soft ground it is often placed over a coarser stone layer.
Base under asphalt. Paving contractors in QP country use it as the compacted stone layer under the blacktop. See tons for a six-inch gravel base.
Base under pavers and patios. QP is a common compacted base under a sand or fine-chip setting bed. Follow the paver maker's base depth.
Shed pads and slab bases. A level, compacted QP pad spreads the load and keeps a shed off wet soil. See our gravel shed foundation guide.
Walkways and path bases. It packs into a walkable surface or a stable base for stepping stones.
Trench backfill and leveling. Contractors use it to backfill trenches and fill low spots where a firm finish matters.

When to pick something else

Drainage. The fines that make QP pack also slow water down. For French drains, around foundation drains and behind retaining walls, use clean stone such as #57 stone.
Directly on wet clay. QP alone can pump mud up through it on soggy ground. A layer of larger clean stone, and often a geotextile fabric, underneath helps.
Decorative beds. QP looks dusty and tracks onto shoes when dry. Washed stone or river rock looks better in planting beds.
A paver setting bed. QP is the base, not the bed. The thin layer the pavers sit in is usually concrete sand or a small chip, per the paver maker.

How much a yard of QP weighs

Dense blends weigh more per yard than clean stone because the fines fill much of the air space. Loose QP usually weighs about 1.4 to 1.6 tons per cubic yard, or roughly 2,800 to 3,200 pounds, depending on the rock type and how wet it is. Trap rock is on the heavy side; recycled concrete is usually lighter. The math below uses 1.5 tons per loose yard. Yards sell QP by the ton, so ask for the supplier's own weight figure if you want a tighter estimate. Our gravel weight per yard chart compares other materials.

How deep to lay QP

Walkways and light patios: about 4 inches compacted on firm soil.
Shed pads: about 4 to 6 inches compacted, extending past the shed footprint.
Gravel driveway top layer: about 3 to 4 inches compacted over an existing firm base.
New driveway or base under asphalt: often 6 to 8 inches or more total, placed and compacted in lifts. Soft soil and heavy trucks call for more.

These are planning ranges. A town permit, a paver maker's instructions or a contractor who has seen your soil should set the final depth.

How many tons of QP to order

Measure length and width in feet and the finished depth in inches, then:

Cubic yards = length × width × depth in inches ÷ 324
Tons ≈ cubic yards × 1.5
Add 10 to 15 percent because QP compacts as it is rolled or tamped, and some is lost to uneven ground

Depth	Approx. area per ton	Tons per 100 sq ft
2 inches	about 108 sq ft	about 0.93
3 inches	about 72 sq ft	about 1.4
4 inches	about 54 sq ft	about 1.9
6 inches	about 36 sq ft	about 2.8

The table is before the compaction allowance, so add the extra 10 to 15 percent to the totals.

Example: a driveway 12 feet wide and 50 feet long, 4 inches deep. 12 × 50 × 4 ÷ 324 = about 7.4 cubic yards. 7.4 × 1.5 = about 11.1 tons. With 15 percent extra, order about 13 tons.

Example: a 10 by 12 foot shed pad, 4 inches deep. 10 × 12 × 4 ÷ 324 = about 1.5 cubic yards. 1.5 × 1.5 = about 2.2 tons. With extra, plan on about 2.5 tons.

To turn tons into deliveries, see how many tons of gravel fit in a dump truck. The base calculator handles other shapes and depths.

Tips for spreading and compacting QP

Prepare the ground. Strip sod and topsoil, then grade the subsoil so water runs off the finished surface.
Work in lifts. Spread and compact about 2 to 4 inches at a time instead of one thick layer. Our post on compacting a gravel base in lifts explains why.
Dampen it. Slightly moist QP packs much better than bone-dry or soaking-wet material.
Use a plate compactor or roller. Rent a plate compactor for patios and pads; driveways go faster with a roller. For small areas, see compacting gravel without a compactor.
Crown or slope the surface. A slight crown or cross slope keeps water from sitting on a driveway and washing out the fines.

Buying tips

Ask for it by name and size. “3/4 QP” and “1 1/2 QP” are different products. If you are outside QP country, ask for crusher run or dense-graded base instead.
Ask whether it is virgin or recycled. Prices and appearance differ.
Check the delivery minimum. Many yards charge a short-load fee under a set tonnage, so it can pay to combine jobs into one delivery.
Plan the drop spot. Have the truck dump close to the work on a hard surface or tarp, clear of septic tanks, soft lawn and overhead wires.

Questions people ask

What is quarry process stone?

Quarry process, or QP, is crushed stone that keeps its fines, usually running from about 3/4 inch down to rock dust. The small particles fill the gaps between larger stones, so it compacts into a firm, fairly smooth layer.

Is QP the same as crusher run?

In practice they are very similar. QP is the common name in New Jersey, the New York metro area and nearby states, while crusher run, crush and run, DGA, Item 4 and 2A are names for comparable dense base blends elsewhere. Exact gradations vary by quarry and spec.

How much does a yard of QP weigh?

Loose QP usually weighs about 1.4 to 1.6 tons per cubic yard, roughly 2,800 to 3,200 pounds, depending on the rock and moisture. Use 1.5 tons per yard for planning and ask your supplier for its figure.

How many tons of QP do I need for a driveway?

Multiply length by width in feet by depth in inches, divide by 324 for cubic yards, then multiply by 1.5 for tons and add 10 to 15 percent for compaction. A 12 by 50 foot driveway at 4 inches needs about 13 tons.

Does QP drain well?

Not as well as clean stone. The fines that let it pack also slow water. Use clean stone such as #57 for French drains and drainage layers, and QP where you need a firm surface or base.

Is recycled concrete QP as good as stone QP?

For many driveways and bases it compacts similarly and costs less. Check the pile for rebar and brick, and keep fresh crushed concrete away from ponds, streams and plantings because its runoff can be alkaline at first.

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