Paver Base Material: What Goes Under Pavers and How Much

The best paver base material is compacted, dense-graded crushed stone, topped with a thin layer of bedding sand. Industry guidance points to 3/4" crushed stone with fines, sometimes sold as 3/4" minus, road base or No. 78 stone, depending on the region. Patios and walkways need a compacted base of at least 4 inches over well-drained soil. Driveways need more. The base does the structural work, and the pavers only sit on top of it.

This guide covers what to buy, how deep to build it, how to compact it, and how to work out the quantity before you place an order.

TL;DR

• Use dense-graded crushed stone (3/4" minus or similar) for the base and a thin layer of bedding sand on top. Pavers never sit directly on soil.
• Minimum compacted base depth is 4" for walkways and patios and 6" for residential driveways. Weak soil or poor drainage means more.
• Compact in lifts of about 4", with the stone slightly moist. Compacting a deep base in one pass leaves the lower layers loose.
• Do not fix a bumpy base with extra sand. Keep bedding sand to roughly an inch.
• Order loose material with a margin for compaction, and have it delivered by the truck load to the site.

Table of Contents

• What actually goes under pavers
• Paver base gravel, rock or decomposed granite?
• Do you need fabric under pavers?
• How thick should the base be?
• Does paver base harden?
• How to prepare and compact the base
• How much paver base material do you need?
• Our perspective: where base jobs go wrong
• Permeable paver bases
• Getting paver base material delivered in San Antonio
• FAQ
• Sources

What actually goes under pavers

A paver surface is a layered system, not one material. From the bottom up:

1. Subgrade: the native soil, excavated, leveled and compacted.
2. Geotextile fabric (sometimes): a separation layer between soil and stone.
3. Aggregate base: compacted crushed stone, the layer this article is mostly about.
4. Bedding layer: a thin course of sand that the pavers are set into.
5. Pavers, joint sand and edge restraints.

Polycor’s installation guide says a paver foundation uses compacted, densely graded crushed stone for the subbase, and it names 3/4", 0 to 20 mm, or No. 78 stone as examples. The same guide notes that dense-graded base materials vary by region, so the local name on the order sheet may differ. The Concrete Masonry & Hardscapes Association (CMHA) calls the base one of the most crucial elements of a durable pavement and says material cost and availability play a key role in what gets chosen.

Why dense-graded stone works

Dense-graded stone contains a range of particle sizes, from 3/4" pieces down to fine dust. The small particles fill the gaps between the large ones, so the stone packs tightly under a plate compactor and forms a firm, stable platform. That is why it is the traditional choice under a sand-set paver surface.

Common paver base options compared

The recycled concrete and concrete sand entries reflect common use in the trade. Always confirm the gradation with your supplier.

Paver base gravel, rock or decomposed granite?

Homeowners often search for “paver base gravel” or “paver base rock” and mean the same thing: angular, crushed stone. Angular is the key word. Rounded gravel, such as pea gravel, rolls under load and does not lock together, so it is a poor structural base. Pea gravel is better used for drainage trenches, around planting beds and as a decorative surface.

Decomposed granite is mostly fines. It compacts into a firm surface for a garden path, but it holds water, can wash out at the edges and does not give a paver surface the same stability as crushed stone with a mix of sizes. For a patio, walkway or driveway, choose crushed stone and keep decomposed granite for the path beside it.

Dense-graded versus open-graded base

Belgard’s technical note explains that dense-graded aggregate has traditionally been paired with a sand setting bed, while open-graded aggregate has grown in popularity and can suit some applications, including freeze-thaw climates. Open-graded stone drains freely because the fines are removed. In San Antonio, where hard freezes are occasional rather than the rule, dense-graded base is the usual choice for patios and driveways. A permeable design is the exception, and we cover it below.

Do you need fabric under pavers?

It depends on the base you build. For an open-graded system, Belgard says that in most cases you should place highly permeable geotextile along the bottom and sides to keep fine-grained soil from migrating into the stone. Without it, the voids clog and the base slowly loses support.

For fine-grained subgrade soils or other water sources, the same note suggests considering a perforated pipe underdrain so the subgrade does not saturate. If your site holds water after rain, plan drainage before you order stone.

Fabric is a separator, not a substitute for thickness. It will not make up for a thin or poorly compacted base.

How thick should the base be?

Thickness depends on traffic, soil type, subgrade drainage and moisture, and climate, according to Polycor’s guide. That guide gives a general minimum of 4" after compaction for sidewalks, patios and pedestrian areas over well-drained soils.

CMHA’s May 2025 guidance lists minimum compacted depths under ideal conditions: 4 inches for walkways and patios, 6 inches for residential driveways and 8 inches for parking lots or residential streets. It adds that weak soil, poor drainage or freezing conditions call for more.

Paver manufacturers often specify more than the minimum. Unilock’s technical guide calls for 6" to 8" for patios and walkways and 10" to 14" for driveways.

If you are choosing between the numbers, build toward the heavier spec when the soil is soft, the area stays wet or a vehicle will ever cross the surface. The extra stone costs far less than lifting and relaying sunken pavers.

Does paver base harden?

Not like concrete. Crushed stone does not cure. It becomes firm because compaction forces the particles together and squeezes out air. Geotechnical references describe how densification expels air from granular material, increasing strength and reducing compressibility.

CMHA’s guide specification asks for aggregate-base compaction to at least 98% Proctor density for pedestrian areas and residential driveways, and at least 98% modified-Proctor density for vehicular areas. You cannot measure that by eye, which is why lift thickness, moisture and the right equipment matter so much.

How to prepare and compact the base

Step 1: Excavate and fix the subgrade

Dig deep enough for the base, bedding sand and paver thickness. Remove unsuitable soil such as organic material or soft spots, then compact and level the subgrade. Polycor’s guide says to excavate unsuitable subgrade and compact it before placing stone. If you are replacing soft ground, clean fill dirt compacted in thin layers is the right material for the job.

Step 2: Place stone in thin lifts

Do not dump 6 inches of stone and run over it once. Unilock notes that typical plate compactors do not compact effectively beyond about 4 inches, so a 6-inch base should go in as multiple 3 to 4-inch layers. Oregon State University Extension suggests about three smaller layers of crushed rock, compacting between each. Polycor says compacting everything at once is a common error.

Step 3: Get the moisture right

Unilock’s technical guide explains that aggregate reaches maximum density only at the right moisture. Most crushed aggregate bases need about 5% to 6% moisture for 100% Standard Proctor density. Too little water compacts only the top portion and can lead to settlement later. A practical field test: the stone should hold together when squeezed, without dripping. If it arrives dry, lightly water it, as Unilock’s installation tips advise.

We cover the same method for driveways and heavier work in our guide to compacting road base in 4 to 6 inch lifts, and in our San Antonio driveway base preparation article.

Step 4: Check the surface before sand

CMHA’s specification says the compacted base should meet roughly plus or minus 3/8 inch over a 10-foot straightedge before bedding sand goes down, and that base errors should not be corrected with extra sand. Iowa State University Extension makes the same point: using excess sand to cover a poor base is a common error, and sand deeper than 1½ inches can produce a washboard surface.

Before you move on, verify base material, thickness, density, tolerances, elevations, drainage and edge restraints, the checklist CMHA’s guide specification lays out.

Step 5: Screed the bedding sand

Keep the setting bed thin and even. During compaction, some sand rises into the joints, where, as Polycor explains, it creates friction that helps distribute loads and lock pavers together. Use washed concrete sand for this layer, not stone dust and not fine masonry sand.

How much paver base material do you need?

Calculate the volume of the finished base, then add a margin because loose stone shrinks when compacted.

1. Multiply length by width (in feet) by compacted depth (in feet). A 6-inch base is 0.5 feet.
2. Divide by 27 to convert cubic feet to cubic yards.
3. Add about 15% to 20% for compaction and waste.

Example: a 12 by 16 foot patio with a 6-inch compacted base is 12 × 16 × 0.5 = 96 cubic feet. Divided by 27, that is about 3.6 cubic yards. With a 20% margin, order about 4.3 cubic yards. Crushed stone commonly weighs somewhere around 1.3 to 1.5 tons per cubic yard, so ask the supplier for the weight conversion for the specific product.

Add the bedding sand separately. At 1 inch over the same area, that is 12 × 16 × (1/12) = 16 cubic feet, a little over half a cubic yard.

A standard dump truck load is far more than a patio needs, so small jobs are often ordered by the yard or ton. Large driveways and parking areas can take several loads, which is where delivery scheduling starts to matter. Our aggregate delivery lead time guide explains how to plan that.

Our perspective: where base jobs go wrong

We haul material to San Antonio job sites every week, and the same few problems come up on paver projects.

• The base is too thin for the use. A patio base that was fine for chairs gets a truck parked on it. If a vehicle might ever cross it, build it as a driveway.
• The stone is dry, or it was dumped and dragged. Stone that is never moistened or compacted in lifts looks flat on day one and settles within a season.
• Wrong material for the layer. Pea gravel as a base, or stone dust as a setting bed, both fail to hold the pavers in line.
• Delivery arrives before the site is ready. Material dumped on an unprepared pad gets contaminated with soil, which reduces the quality of the base.

Our advice: finish excavation and subgrade compaction first, then schedule stone for the same day or next day so it goes straight into the lifts. When you request a quote, tell us the project type, the area, the compacted depth and the stone spec you were given. We will confirm what we can deliver for it, with per-load pricing and GPS-tracked trucks, so you know when the load arrives.

— BRIAN

Permeable paver bases

If your site needs stormwater to pass through the surface, the base changes. Permeable systems use open-graded stone in several layers instead of dense-graded stone, and often include fabric and sometimes an underdrain. Our guide to a 3-layer permeable paver base to agency specs walks through the layers. Do not mix the two approaches: dense-graded stone in a permeable design blocks the drainage you are building it for.

Getting paver base material delivered in San Antonio

Buying by the truck load is usually cheaper per ton than bagged or pickup-truck quantities, and it saves several trips. We deliver road base and aggregates, sand and fill dirt across Greater San Antonio, with same-day or next-day dispatch. Browse the full list of materials and hauling services, or look at our #2 road base for base layers on larger jobs. When the excavation produces spoil, old concrete or a pile of demolition debris, our dump truck haul off service is $275 per truck load. Request a quote from the O’Leary Development Group site with your dimensions and we will help you size the order.

FAQ

What base should I put under pavers?

Use compacted, dense-graded crushed stone, such as 3/4" minus, in lifts of about 4 inches. Finish with roughly 1 inch of washed concrete sand as the setting bed. Build at least 4 inches for patios and walkways and at least 6 inches for a residential driveway, more if the soil is soft or wet.

Do I need gravel under pavers?

Yes. Pavers set straight on soil move with moisture changes and settle unevenly. Use angular crushed stone for the base rather than rounded pea gravel, which does not lock together under load.

What kind of fabric goes under pavers?

A permeable, non-woven geotextile that separates the subgrade from the stone. It is most important with open-graded bases, where it keeps fine soil out of the voids. It goes along the bottom and sides of the excavation, below the stone and never on top of it.

Does paver base harden?

It does not cure like concrete. It becomes firm through compaction, which packs the particles together and removes air. Correct moisture and thin lifts are what get it to the density specifications ask for.

Can I use decomposed granite instead of crushed stone?

It works for a garden path, but for a patio, walkway or driveway crushed stone with a range of particle sizes is the more stable and better-draining choice.

Sources

• Polycor: Pavers installation guide
• Polycor: Bedding layer
• CMHA: Proper concrete paver base and depth
• CMHA: Guide specification for the construction of interlocking concrete pavement
• Belgard: Technical note on open-graded aggregate with concrete pavers
• Unilock: Basic technical guide
• Unilock: Advanced technical guide
• Unilock: Base preparation tips
• Oregon State University Extension: 10-step guide to installing pavers
• Iowa State University Extension: Installing concrete pavers, part two
• Iowa State University InTrans: Geotechnical chapter

Recommended

• DIY & Pros: Build A 3-Layer Permeable Paver Base To Agency Specs
• 5 Permeable Driveway Materials And Reservoir Rules For Owners & Pros
• 95% Compaction And 4 Inch Lifts: San Antonio Driveway Base Preparation