Stone 6mm, 9mm, 13mm, 19mm and 38mm

The terms 6 mm, 9 mm, 13 mm, 19 mm, and 38 mm stone refer to the nominal size of crushed aggregate used in construction. Each size has different applications depending on the required strength, finish, drainage, and structural performance.

Stone SizeCommon NameTypical UsesWhy It's Used
6 mmCrusher chipsConcrete paving, floor screeds, precast products, asphalt, pathwaysProduces a smooth finish and fills small voids.
9 mmSmall aggregateHigh-strength concrete, slabs, driveways, thin concrete sectionsBetter compaction where reinforcement is closely spaced.
13 mmStandard concrete stoneFoundations, suspended slabs, columns, beams, precast concreteExcellent balance between strength and workability.
19 mmGeneral building stoneHouse foundations, floors, reinforced concrete, retaining walls, structural concreteThe most commonly used aggregate for residential construction.
38 mmLarge aggregateMass concrete, dam walls, bridge foundations, road sub-base, drainageReduces cement requirements in large pours and provides excellent stability.

6 mm Stone

Best for:

  • Paving blocks

  • Decorative concrete

  • Thin concrete toppings

  • Floor screeds

  • Asphalt

Advantages

  • Smooth finish

  • High compaction

  • Ideal for detailed work

9 mm Stone

Best for:

  • Driveways

  • Reinforced slabs

  • Concrete countertops

  • Water features

  • High-strength concrete

Advantages

  • Fits around dense reinforcement

  • Strong finished concrete

  • Better surface quality

13 mm Stone

Best for:

  • House slabs

  • Columns

  • Beams

  • Precast lintels

  • Structural concrete

Advantages

  • Excellent concrete strength

  • Easy to pump

  • Good workability

19 mm Stone

This is the most commonly used building stone in South Africa.

Best for:

  • House foundations

  • Concrete floors

  • Strip footings

  • Retaining walls

  • General reinforced concrete

Advantages

  • High strength

  • Economical

  • Good drainage

  • Suitable for almost all residential construction

38 mm Stone

Best for:

  • Dam construction

  • Bridge foundations

  • Heavy industrial floors

  • Road base

  • Drainage systems

  • Gabions

Advantages

  • Extremely stable

  • Excellent drainage

  • Requires less cement in mass concrete

  • Ideal for heavy loads

Typical Uses Around a House

ProjectRecommended Stone
House foundations19 mm
Concrete slab19 mm
Reinforced beams13 mm
Columns13 mm
Driveway13 mm or 19 mm
Garden pathways6 mm
Decorative landscaping6 mm
Drainage trenches19 mm or 38 mm
French drains19 mm or 38 mm
Septic soakaway38 mm
Retaining walls19 mm
Paving blocks6 mm

Which Stone is Most Popular?

For general construction:

  1. 19 mm – Most common for residential concrete.

  2. 13 mm – Preferred for structural concrete with dense reinforcement.

  3. 6 mm – Used for finishing work and paving.

  4. 38 mm – Used for drainage and large-scale construction.

  5. 9 mm – Used where finer aggregate is needed.

Typical Concrete Mixes (Residential)

ApplicationStone Size
House slab19 mm
Foundation footing19 mm
Concrete driveway13 mm or 19 mm
Columns13 mm
Beams13 mm
Suspended slab13 mm
Garden edging6 mm
Drainage38 mm

Simple Rule of Thumb

  • 6 mm = Fine finishing and paving.

  • 9 mm = Thin, high-strength concrete.

  • 13 mm = Structural reinforced concrete.

  • 19 mm = General-purpose concrete for most buildings.

  • 38 mm = Heavy-duty foundations, drainage, and road construction.

For most residential building projects in Southern Africa, 19 mm crushed stone is the standard choice for foundations and slabs, while 13 mm is often selected where reinforcement is closely spaced or a smoother concrete finish is required.

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