Non-hydraulic lime
England in 2008, defines non-hydraulic lime (or putty lime) as: ‘Lime which will not set by chemical reaction with water but requires exposure to carbon dioxide in the air in order to harden. Unlike hydraulic limes (see Hydraulic lime), it is derived from pure limestone. It is commercially available in powder (hydrated) or putty form.’
Short Guide, Lime Mortars in Traditional Buildings, published on 1 March 2013 by Historic Scotland, defines putty lime as a: ‘Hydrated lime binder that has been slaked with an excess of water forming a wet paste that can be left to mature over time.’
Society for the Protection of Ancient Buildings (SPAB) definition online Glossary defines lime putty as: 'Calcium hydroxide (Ca(OH)2) formed as a paste when a non-hydraulic or weak (NHL 2) hydraulic lime is slaked in an excess of water and the milky suspension is allowed to settle. Can also be made by mixing hydrated lime (the form widely available in builders' merchants) and water, although this gives a less workable mix with inferior plasticity and binding properties.'
See also: Hydraulic lime.
[edit] Related articles on Designing Buildings
Featured articles and news
Homes England creates largest housing-led site in the North
Successful, 34 hectare land acquisition with the residential allocation now completed.
Scottish apprenticeship training proposals
General support although better accountability and transparency is sought.
The history of building regulations
A story of belated action in response to crisis.
Moisture, fire safety and emerging trends in living walls
How wet is your wall?
Current policy explained and newly published consultation by the UK and Welsh Governments.
British architecture 1919–39. Book review.
Conservation of listed prefabs in Moseley.
Energy industry calls for urgent reform.
Heritage staff wellbeing at work survey.
A five minute introduction.
50th Golden anniversary ECA Edmundson apprentice award
Showcasing the very best electrotechnical and engineering services for half a century.
Welsh government consults on HRBs and reg changes
Seeking feedback on a new regulatory regime and a broad range of issues.
CIOB Client Guide (2nd edition) March 2025
Free download covering statutory dutyholder roles under the Building Safety Act and much more.
Minister quizzed, as responsibility transfers to MHCLG and BSR publishes new building control guidance.
UK environmental regulations reform 2025
Amid wider new approaches to ensure regulators and regulation support growth.
BSRIA Statutory Compliance Inspection Checklist
BG80/2025 now significantly updated to include requirements related to important changes in legislation.