The short answer
A conventional sand-set interlocking concrete paver assembly commonly uses a compacted aggregate base beneath a distinct bedding-sand course. CMHA’s guide specification covers concrete pavers and bedding sand over a compacted aggregate base for pedestrian and vehicular applications. The exact aggregate gradation, local product name, thickness and quality requirements belong to the project specification—not a generic calculator.
Ask for a specification, not a nickname.
“Road base,” “crusher run,” “Class 5,” “ABC” and similar names can describe different products across regions. Obtain the gradation or approved product for the selected system.
Two broad base-system families
| System | General characteristic | Key caution |
|---|---|---|
| Dense-graded aggregate base | Blend of particle sizes compacted into a dense layer | Drainage and fines behavior must match the design |
| Open-graded aggregate base | Angular aggregate with open voids for drainage | Not a drop-in substitution; bedding, joints, edge and drainage details change |
| Permeable interlocking pavement | Designed surface, joints and reservoir layers manage water | Requires a complete permeable-pavement design |
CMHA’s FAQ describes standard sand-set pavers over dense-graded aggregate as the recommended assembly for most standard interlocking concrete paver applications. It also describes open-graded alternatives with specific limitations. Do not swap only the base stone while leaving every other layer unchanged.
Base aggregate, bedding and joint material do different jobs
Aggregate base
The thicker structural layer above prepared soil. Its gradation, strength, drainage behavior, placement and compaction support the pavement system.
Bedding course
The controlled setting layer immediately below pavers. CMHA guidance for conventional systems and manufacturer instructions define the appropriate sand or small aggregate and nominal thickness.
Joint material
The material installed between pavers. It contributes to the finished system but is not the same material-volume task as the base or bedding course.
The sand calculator deliberately estimates bedding quantity separately. It does not assume that bedding and joint products are interchangeable.
Seven supplier questions
- What is the exact product name and gradation?
- Is it approved for the selected paver system and traffic?
- Is the quoted density loose, delivered or compacted?
- Does the yard sell by short ton, metric tonne, cubic yard or bag?
- What is the minimum load and delivery charge?
- What moisture or stockpile variation should the order allow?
- What bedding and joint materials pair with this base?
Translate the selected material into calculator inputs
| Supplier answer | Calculator field | Do not assume |
|---|---|---|
| Delivered density | Base density | Site default is exact |
| Specified compacted thickness | Base depth | Every patio uses 4 in |
| Loose-order conversion | Compaction allowance | 15% always applies |
| Handling/grade overage | Waste allowance | More is automatically safer |
| Price per ton | Optional price | Delivery and tax are included |
Material-selection mistakes to avoid
- Choosing rounded decorative gravel because the stone size looks similar.
- Calling every fine aggregate “sand” without separating bedding and joints.
- Mixing a permeable base detail with conventional sand-set instructions.
- Filling low spots in the base with excess bedding material.
- Using a web density after the local supplier can provide a product-specific value.
- Calculating tons before confirming whether the supplier sells by volume or weight.
References
- CMHA PAV-GSP-011 — Interlocking Concrete Pavers on an Aggregate Base
- CMHA PAV-FAQ-002 — Standard Pavers on Open-Graded Aggregates
- CMHA PAV-TEC-018 — Permeable Interlocking Concrete Pavement Systems
- QUIKRETE — Patio Paver Base Sand product information
Scope
This comparison helps organize supplier questions. It does not approve an aggregate source, design a permeable system or replace the paver manufacturer and project specification.