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Cornish Lime CLM28F Fibered Coarse Putty Mortar & Basecoat Render
A fibered mortar and render with a coarse texture for building or as a basecoat renders.
Cornish Lime CLM28 Coarse Lime Putty Mortar & Basecoat Render
A popular coarse buff multipurpose mortar and render for building work or as a basecoat render.
Cornish Lime CLM35 Fine Lime Putty Mortar & Topcoat Render
A multipurpose mortar and render with a fine texture and buff coloured finish for narrow joint.
Why lime putty mortars?
Lime has been the principal binder in mortars, renders and plasters for a millennia worldwide, and here in the UK most buildings constructed before 1900 were built using lime. Lime putty mortars fall within the wider category of non-hydraulic lime mortars.
Produced by slaking calcium oxide (quicklime) with water to form calcium hydroxide, lime putty remains one of our core products at Cornish Lime. We have manufactured high-calcium lime putty since 1993, using quicklime sourced from Buxton, Derbyshire, and matured traditionally in pits after slaking.
Non hydraulic lime mortars, including lime putty mortars, harden through carbonation as they react with carbon dioxide in the air. The process needs moisture and takes longer than their non-hydraulic counterparts. However, the result is a softer, porous and more flexible material that not only helps to manage moisture within the building fabric, but accommodates the subtle movement of traditional buildings to support the long term health of the building fabric.
Unlike modern cavity wall construction, solid-walled buildings rely on breathable materials to manage the moisture always present in the fabric. Lime putty mortars are suitable for a wide range of masonry types, including stone, brick, cob and modern wood-wool carrier boards, making them ideal for traditional solid-walled buildings.
Combined with carefully selected sands chosen for their mineralogy, colour and texture, our mature lime putty mortars are a trusted choice for experienced builders, skilled craftspeople and informed DIY users alike. Looking for lime putty plaster or render? Browse our full range.
Available in 20kg tubs, mini bags or bulk bags, ready for local or nationwide delivery.
Need help choosing the right product? Our in-house experts can advise on suitable lime mortars for your next building or pointing project. Buy online or open a trade account with convenient delivery options across the UK.
Need support? Get in touch with the team.
Get In TouchFAQs
Premixed lime putty mortars are a great option for beginners, as they can be used directly from the bag or tub, with only the need to give it a quick mix or knock it up to ensure the correct consistency. Further opened bags or tubs can be resealed and when stored properly can be opened by back up and used.
Non-hydraulic lime, sometimes called “fat lime” is a lime, if left underwater, will never set or harden, increasing in strength only by absorption of atmospheric carbon dioxide through carbonation. Lime putty mortars are a type of non-hydraulic lime mortar made with lime putty, giving them a high calcium carbonate content, and their popular feel on the trowel. Another traditionally used non-hydraulic mortar would be a hot mixed mortar.
It offers excellent breathability, flexibility, and compatibility with solid walled masonry like stone, brick or cob and can be an ideal choice for weakened substrates that require a weaker mortar. Working with a historic mortar? Learn more about our mortar matching service.
Lime putty mortars don’t necessarily “set”, rather they gain strength through a process called carbonation. While in the initial few days after application the material will firm up and build up strength, full carbonation can take weeks to months, depending on temperature and humidity.
As lime putty mortars rely on carbonation to build strength it’s ability to be used in damp, wet and cold environments is limited. As such, we always advise using lime putty mortars externally when the swallows are home, roughly from April to September or October.