Paving Bed Estimator

This form will calculate the approximate metric tonnes of sand and/or sand & bags of OPC required for the entered area.


Length in Metres
Width in Metres
Area in Sq Meters


Sand Only


Sand and Cement

Sand In tonnes Sand and Cement In tonnes
  Cement in Kg
  Cement in 25Kg bags

Mortar Bedding

Slabs can be 'spot-bedded' with a small mound of mortar at each corner and one in the middle; whilst this is easier to adjust and correct than other types of bedding it is also weaker.

A full mortar bed provides the strongest support but can make it difficult to get the slabs true and level.

Box and Cross bedding is a good compromise; providing good support while allowing the mortar to squeeze sideways during levelling.

Basic laying steps

  • With a trowel place strips of mortar so that they form a rectangle slightly smaller than the slab dimensions, enclosing a cross strip. The cross strips can be omitted for small square slabs, but large rectangular slabs may need to be double-crossed. The strips should be 30-50mm high
  • Position the first slab on the mortar bed and temp it level with a wooden or rubber mallet or a length of timber. It should not rock in any direction. Check for accuracy in both directions
  • Repeat with successive slabs. Joint width will depend on the dimensions of the units, but will generally be 10-12.5mm
  • Check alignment and level against adjoining slabs with a straight edge spanning two or more flags