What Kind of Sand Goes Under Pavers?

For the conventional sand-set interlocking concrete pavement covered by CMHA construction guidance, use bedding sand meeting the specified concrete-sand grading and quality requirements. Polymeric joint sand belongs between units; it is not the bedding layer. Permeable, panel, mortar-set and other systems can require different materials.

What the bedding layer does

The screeded bed supports placement of units over the prepared base and helps the installed assembly develop interlock during compaction. It provides a uniform setting layer. It is not a substitute for the selected structural aggregate base and should not be used to hide low spots in that base.

Choose the pavement system first. If the selected detail calls for conventional concrete sand, order that material. If it calls for small open-graded aggregate or a proprietary leveling layer, follow that complete detail rather than replacing it with a familiar sand name.

Concrete sand and ASTM C33

ASTM C33/C33M specifies aggregate grading and quality for concrete. CMHA uses that material context for conventional bedding and adds application guidance. The ASTM reference does not independently set a one-inch bed, a density, bag weight or purchase allowance.

“Concrete sand” on a yard sign is a useful starting description, but ask for a material sheet or confirmation that the delivered sand meets the project’s specification. Do not infer compliance merely from coarse appearance. Fine aggregate can be natural or manufactured; source name alone does not establish its suitability.

For vehicle pavements, CMHA’s bedding selection bulletin considers durability as well as grading. A sieve distribution is not the whole performance question under repeated traffic.

Materials that should not be confused

A package marked “paver sand” can still be ambiguous. Read its intended use and technical information: does it describe material below units, between units, or an entire proprietary assembly? The bedding versus joint sand guide makes those locations explicit.

Exceptions need their own detail

Permeable paving uses compatible open-graded joint and bedding aggregate in the system described by CMHA PAV-TEC-018. Replacing those joints with an ordinary polymeric product or installing fine sand where the detail calls for angular aggregate can change the intended water path.

Likewise, concrete overlays, porcelain products, paving slabs and base panels have system-specific instructions. Unit appearance does not establish that the conventional sand-set detail applies. Verify the paving manufacturer’s assembly and the base-system instructions together.

What to confirm before delivery

Request the material specification, grading information and any required durability information for the application. Confirm whether the supplier sells by volume or weight and what bulk-density condition its conversion describes. Keep delivered bedding material from being mixed with soil or a different aggregate stockpile.

Resolve bedding depth separately from material choice. Using the right sand at an inconsistent thickness does not correct an uneven base.

After choosing the specified material and screeded depth, enter the paved area in the Paver Sand Calculator. It estimates bedding volume; enter supplier density and actual package weight only if converting that volume into weight or bags.