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Pointing Calculator SPEC.ESTIMATOR // BS EN 998-2

Calculation Methodology & Physical Derivations

Every figure produced by pointingcalculator.com is backed by standard geometric formulas and established masonry specifications.

1. Cavity Volume Equation

For any direct joint cavity, base volume equals total joint length multiplied by visible joint face width multiplied by repointing fill depth.

Vcavity = Ltotal × wj × dr

2. Regular Masonry Module Derivation

In a running bond wall, the repeating module has dimensions (Lu + wj) by (Hu + wj). The continuous bed joint length is (Lu + wj) and the head joint is Hu. The sum (Lu + Hu + wj) divided by module area yields exact linear metres of joint per square metre without double-counting corner intersections.

kj = (Lu + Hu + wj) / ((Lu + wj) × (Hu + wj))

3. Cited Technical Standards

Our presets and material yields conform to: BS EN 771-1 (Clay masonry), BS EN 771-3 (Aggregate concrete units), BS EN 998-2 (Mortar specifications), SPAB Technical Q&A 24, and NPS Preservation Briefs 2.

  • BS EN 771-1:2011 — Clay masonry units
  • BS EN 771-3:2011 — Aggregate concrete masonry units
  • BS EN 771-4:2011 — Autoclaved aerated concrete masonry units
  • BS EN 998-2:2016 — Specification for mortar for masonry
  • BS 3921 — Specification for clay bricks (historic imperial)
  • BS EN 459-1 — Building lime definitions, specifications and conformity criteria
  • SPAB Technical Q&A 24 — Repointing
  • NPS Preservation Briefs 2 — Repointing Mortar Joints in Historic Masonry Buildings
  • Historic England — Practical Building Conservation: Mortars, Renders & Plasters