Pointing Principles

Q: why should the mortar used to bed and point masonry walls be softer and more permeable than the stone or brick forming the wall.

For advice on appropriate mortar mixes call Luxton Chartered Surveyors.

A: to allow moisture to migrate to and evaporate through the mortar joints. This helps prevent certain salts related and frost damage to the masonry.

In the illustration the mortar although not a particularly strong cement mortar is harder than the relatively soft blue lias stone surrounds, and is resulting in accelerated decay.

Recommended Publications
Anyone looking for simple no-nonsense guidance on the use of cob and lime is recommended to two useful and inexpensive practical guides: “Cob buildings” and “Lime in building” produced by Jane Schofield with Jill Smallcombe available through the Black Dog Press.
https://theblackdogpress.bigcartel.com