Lime Putty

Lime Putty in mortar, render and plaster: traditionally, the main use for Lime putty would have been in renders and plasters having been allowed to mature for a period of several months, or sufficient time to allow all the quicklime in the form of calcium oxide to fully convert to calcium hydroxide. Whereas traditional building mortars were made from quicklime and sand mixed together in a process we today call Hot Mixed Lime this was a simpler process which yielded a lime rich mix ideal for most aspects of masonry.

However, Lime Putty today is used for all aspects of construction, although some are clearly not appropriate for this material as its virtue can sometimes be its downfall, although there is no doubt that it produces the most vapour permeable of lime mortars.

Lime Mortar:

Putty when mixed with Sand, usually at a mix ratio of 1:3 or 2:5 will make a lime mortar. Hair, Fibres or Pozzolans can be added to the mix to modify certain characteristics of the mortar.

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Advantages

• Lime Putty yields the best lime plaster bar none.
• Very easy to use (fatty) mortars, renders and plasters.
• Very vapour open (breathable) mortars.

Limitations:

• Can be more demanding in terms of its aftercare.
• Will not work in damp or wet environments. No chemical set, carbonation only.
• Limited use during the colder months – only use outside when the swallows are home, usually between April and October.

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