Lime mortar for repointing and building. NHL grades, mix ratios, and when to use lime mortar instead of cement.
Cornerstone · 8 min read · with breathability calculator
Lime mortar lets walls breathe, absorbs movement, and protects soft bricks. Cement mortar is harder, waterproof, and can trap damp or crack historic masonry. When to use each, costs, application, and the evidence from Historic England, BRE, and 20 years of field monitoring.
Cornerstone · 9 min read · with mix calculator
The correct lime mortar mix ratio depends on exposure, masonry type, and NHL grade. Learn standard ratios (1:3, 1:2.5, 1:2), how to adjust for sheltered vs exposed locations, aggregate grading, and batch mixing for consistent results. Includes Interactive mix calculator.
The most common hydraulic lime grade for UK repointing and building work.
NHL 2, 3.5, and 5 grades compared: strength, set time, and when to use each.