ABC base for pavers — our standard base specification for paver patios in Arizona.

What ABC actually is

ABC stands for Aggregate Base Course. It's a graded mix of crushed rock running from about 3/4" at the top end down to fines (basically rock dust) at the bottom — all in one bag. That blend is what makes it work as a structural base.

• The big rock interlocks and carries load
• The medium aggregate fills the gaps between the big rock
• The fines fill the voids between the medium rock so nothing can shift
• When compacted at the right moisture, it becomes nearly as solid as concrete — but still permeable
• It sheds water sideways instead of holding it like clay or sand

Why ABC is the right base under pavers in Arizona

• Phoenix soil is mostly caliche, clay, or loose decomposed granite — none of it stable enough to set pavers directly on
• Monsoon storms dump 1–3" of rain in an hour; the base has to drain that water laterally, not pond it
• Pavers need a base that won't settle or shift under load — driveways especially have to hold up to a 4,000 lb SUV every day
• Caliche under your yard expands and contracts seasonally; ABC isolates the pavers from that movement
• ABC handles the temperature swing (35° winter nights to 115° summer days) without breaking down

How deep the ABC layer should be — AE's standard spec

These are the depths we actually install. They're the answer that lasts, not the minimum that gets past inspection. If site conditions, soil, build-up grading, or higher-traffic use call for more, we install additional ABC — the spec scales up, never down.

• Standard residential patio: 2–3" compacted ABC
• Standard walkway: 2–3" compacted ABC
• Standard residential driveway: 4–6" compacted ABC
• Build-up areas (regrading low spots, raising a deck): additional ABC stacked in 2–3" lifts to required height
• Higher-traffic, commercial, or RV/boat pads: additional ABC depth + geotextile fabric as conditions warrant
• Pool deck pavers: 2–3" compacted ABC plus engineered grading away from the coping
• On top of every base, every time: 1" of screeded bedding sand, then pavers, then polymeric joint sand

Installation in lifts (this is where shortcuts happen)

You cannot dump base material into a hole and compact it from the top — the bottom stays loose. ABC has to go in in 2–3" lifts, each one compacted before the next goes on. A real install looks like:

• Excavate to the right depth (base + 1" sand bed + paver thickness)
• Inspect and compact the subgrade — loose native soil under the base ruins everything above it
• Spread first 2–3" lift of ABC, mist with water to optimum moisture
• Run a plate compactor in overlapping passes — typically 4–6 passes per lift
• Add additional lifts as the spec calls for, each compacted before the next
• Final lift gets the most attention; surface should ring solid under the compactor
• Screed 1" of bedding sand on top of the finished ABC, then set pavers, then polymeric joint sand

Compactor matters too

• Patios: a 3,000–5,000 lb-force forward-plate compactor is the minimum tool
• Driveways and pool decks: a reversible plate compactor (8,000+ lb-force) or a roller
• A hand tamper is fine for tight spots and final detail near walls — not for the whole patio
• If a crew shows up to a 600+ sq ft patio with one small tamper, the base will not be properly compacted

Red flags when a contractor quotes a paver job

• No mention of base material or depth in the quote
• Quote uses 'road base' generically without specifying ABC and depth
• Crew arrives with quarter minus instead of ABC (see our quarter minus warning page)
• Single dump of base material with no plan to compact in lifts
• No water on site during base install (dry compaction doesn't work)
• Pricing dramatically below other quotes — base depth is usually where they cut
• Pavers being set directly on native soil or on a thick sand layer with no aggregate base

What ABC costs (so you know what you're paying for)

ABC is not the expensive part of a paver job — labor and excavation are. Even on a driveway with the full 4–6" of ABC, the material runs a few hundred dollars on a base that determines whether the $8,000 patio lasts 5 years or 30. There is no good reason to cheap out here.

How AE installs ABC under every paver job

• Base depth spec'd in the proposal in inches (2–3" patios/walkways, 4–6" driveways, more where conditions call for it)
• Subgrade inspected and compacted before any ABC goes down
• All ABC installed in 2–3" lifts with plate or reversible-plate compaction
• Moisture added during compaction — every lift, every time
• 1" of screeded bedding sand on top of the finished base — always
• Polymeric joint sand swept into every joint and activated — always
• Photo documentation of base depth and compaction on every job