Frequently Asked Questions

Below is a selection of queries received by the BLF over the years and answers from correspondents. The answers are those of the correspondent and not those of the BLF. Information about lime technology is growing and changing, so an answer given below might not be the answer that would be given today.

Most importantly, information about materials and their application should not be included in specifications without taking into account the appropriate use for location, climate, type of building, method of construction, quality of workmanship, detailing, the effect on adjacent materials, etc. The BLF recommends professional advice is sought for answers to site-specific queries. The Building Limes Forum is not an accrediting organisation for the manufacture, supply or use of lime and therefore cannot recommend suppliers, craftsmen or professionals. See Sources of Information for websites that do supply this information. You may also find it helpful to refer to the Bookstall and Courses in Lime on this website which may well provide the source of further relevant information and answers to questions.

• Lime Production and Supply
• Standards, Codes and Building Regulations
• Masonry Construction
• Floor Construction
• External Finishes
• Internal Finishes

If you have a question, or can provide other answers, please email us.

Lime Production and Supply

Aged Lime

Q What age can you buy lime in the UK?

The Cost of Lime

Q Why is hydrated lime more than double the price of Ordinary Portland Cement?

Old Hydrated Lime

Q Are old, unopened sacks of hydrated lime of any use?

Standards, Codes and Building Regulations

Code of Practice

Q Is there a Code of Practice on the way?

Building Control Officers & Lime Mortars

Q Has anyone persuaded BCO’s that adding waterproofer to re-pointing is unwise in a stone/lime mortar building?

Masonry Construction

Frost and Curing Lime Mortar

Q Has anyone else been caught by this year's frost?

Sulfate Attack

Q Why doesn't sulfate attack affect hydraulic lime mortar?

Lime in New Build

Q Lime mortar for new build: where is it at now?

Lime Concrete

Q My clients have requested that I find a “healthy” concrete.

Hydraulic Lime and Pulversied Fuel Ash

Q Has anyone experience of brick pointing using lime mixed with coal-derived fuel-ash?

Black Ash Mortar

Q How can we match a black ash mortar?

Coloured Mortar

Q Anyone know how the pink mortar colour was derived?

Floor Construction

Lime for Bedding

Q stone floor slabs bedded with a mix of 3 parts sharp sand to one part hydraulic lime have become loose.

Lime Ash Floor

Q Would a lime ash floor be durable with in-floor heating?

External Finishes

Cracking in Cornice

Q Five months after restoring a 19th century plastered brick cornice in India I am seeing hair-line cracks.

Internal Finishes

Lime Plaster in a Shower

Q Can hydraulic lime be used as a plaster wall in an indoor shower that will have tiles installed over it?

Lime and Chalk Plaster (no sand)

Q Has anyone had experience of using lime and chalk plaster with no sand for plastering over oak laths?

Anthrax Spores

Q Are there any references about contamination of horsehair plaster with anthrax spores?

Guild of Plasterers

Q I am trying to contact the Guild of Plasterers but am unable to find contact details. Can anyone help?

Any More?

If you have a question about building lime, or can provide other answers to any of the questions above, please contact us.