[stonecalc id=”2a-modified-stone”]
2A Modified Stone Calculator Guide
Ask for “2A modified” at a quarry in Pennsylvania and everyone knows exactly what rolls onto the scale: the PennDOT-specified dense-graded aggregate that underlies most of the driveways, garage pads, and farm lanes in the state. Ask for it two states away and you may get a blank look — not because the product does not exist there, but because it wears a different name. This calculator prices the material itself: 1.55 tons per cubic yard, with a 15% compaction allowance built into the default.
The “modified” in the name is the working part. Plain 2A is a graded stone; the modified version is blended with extra fines so that, compacted damp, it sets up almost like a weak pavement. That behavior — hard crust on top, structural mass below — is what people are really ordering.
What Is 2A Modified Called in Other States?
Dense-graded base stone is the most regionally renamed product in the aggregate business. If you know one column of this table, you know them all:
| Region | Local name | Same essential product |
|---|---|---|
| Pennsylvania | 2A modified | Dense-graded, 3/4 in top size with fines |
| New Jersey / New York | DGA or QP (quarry process) | Yes |
| Virginia | 21A / 21B | Yes |
| North Carolina | ABC (aggregate base course) | Yes |
| Southeast generally | Crusher run | Yes |
| Upper Midwest | Class 5 | Yes |
| Mountain West | Road base | Yes |
Putting 2A Modified to Work
- Car driveways: 4 inches compacted over firm subgrade; 6 inches where the ground stays damp.
- Truck and equipment lanes: 6–8 inches in two compacted lifts, over geotextile on soft soils.
- Shed and hot tub pads: 4–6 inches, screeded level and compacted to refusal.
- Under pavers and walls: 4 inches minimum as the structural course beneath the bedding layer.
- Compact it damp: a light watering before each compactor pass activates the fines and produces the signature hard-set surface.
If your supplier lists the product under its generic name, the crusher run calculator runs the identical math, and mid-Atlantic readers outside Pennsylvania will find their local terminology in the DGA calculator.
[stonecalc_faq id=”2a-modified-stone”]