I'm repointing a Victorian stone house using lime motor and have been given contradictory opinions on the use of plasticiser in the mortar. Using a 3:1 sand to lime mix. Some people say it's unnecessary, some say it will make the mortar more workable. What's the opinion here and are there chemicals in the plasticiser which will actually be detrimental to the mortar in the long term?
Plasticiser in lime mortar FAQ
Oct 23, 2024
Last reply: 1 year ago
3 Replies
Don't know about lime mortar, but I seem to remember the principal reason for plasticer was to reduce the water content for a given degree of workability, and so an increase in strength. But for lime mortar I thought its primary claim to fame was it was weaker and more "forgiving" on movemnet etc of the stone or brick, so extra strength would be deleterious
Would also affect how porous it is - another key attribute of lime mortar.
Probably best check with a specialist lime mortar supplier or a 'heritage' builder.
Ive used as lot of lime and cement mortar in various combinations of lime:cement
High lime content never really sets hard as such. I cant see why a plasticiser would be needed
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