Concrete Sand
Also known as: sharp sand, C-33 sand, bedding sand
Concrete sand is a coarse, washed sand with angular grains, used to mix concrete and mortar and as a leveling bed under pavers and flagstone. Its coarse texture gives strength and drainage.
In simple terms
Concrete sand is the gritty, coarse sand that goes into concrete and under pavers. The grains are larger and sharper than play or mason sand, which is what makes mixes strong and paver beds stable.
In depth
Concrete sand is washed to remove silt and graded coarse (often to an ASTM C-33 spec). The angular, well-graded particles interlock and bond with cement paste, giving concrete its compressive strength, and they create a free-draining, stable setting bed for pavers. As bedding it is screeded to about 1 inch; going thicker invites settling. It is distinct from fine mason sand (smoother, for mortar joints) and from fill sand (cheaper, unwashed, for backfill).
Why it matters
Using the right sand is structural: concrete sand’s coarse, washed grading is what gives concrete strength and keeps paver patios from settling unevenly.
Common mistakes
- Substituting fine mason or play sand in concrete, which weakens the mix.
- Screeding a paver bed too thick, which leads to ruts and settling.
Examples & uses
- Mixing concrete and base for mortar.
- Leveling/setting bed under pavers and flagstone.
- Pipe and utility bedding.