Lime Mortars

Explore our range of ready mixed hydraulic and non-hydraulic lime mortars for building, pointing, rendering and plastering. Convenient and easy-to-use, premixed lime mortars offer quality-controlled production and consistency, helping to reduce colour and performance variation and simplify mixing onsite. So whether you’re looking to buy a lime mortar for building conservation, renovation, or new build, our in-house expert team can help advise.

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Cornish Lime Putty Mortar CLM28

Coarse Putty Mortars

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Premium ready-mixed coarse lime putty mortars for pointing, coarse or basecoat renders.
From £7.51 £9.01 Inc VAT
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Cornish Lime Fine Putty Mortars Renders and Plasters

Fine Putty Mortars

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Premium ready-mixed fine lime putty mortars for pointing, fine renders and plastering.
From £7.81 £9.37 Inc VAT
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Hot Mixed Mortar CLH28

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An easy-to-use light cream ready-mixed coarse hot mixed mortar for building & pointing.
£292.76 £351.31 Inc VAT
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Cornerstone Drymix Lime Mortar Range

Cornerstone Drymix Mortar

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A breathable ready mixed multi-purpose lime mortar for pointing and general building work.
From £12.56 £15.07 Inc VAT
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Cornerstone Insulating Render and Plaster

Cornerstone Insulating Render

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A lightweight render for improved insulation and thermal performance of solid wall masonry.
£15.55 £18.66 Inc VAT
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Cornerstone Promix Lime Render and Plaster Range

Cornerstone Promix Render & Plaster

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A lime render and plaster with workability, reduced chance of shrinkage and an improved cure.
From £14.58 £17.50 Inc VAT
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Cornerstone Harbour Mix Lime Mortar

Cornerstone Harbour Mix Mortar

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A fast-setting, sulphate-resistant and durable waterproof mortar for marine environments.
£16.03 £19.24 Inc VAT
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Cornerstone Heritage Masonry Grout Range

Cornerstone Heritage Masonry Grout

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A pumpable cement-free grout for void filling and consolidation of historic solid masonry.
From £25.3 £30.36 Inc VAT
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Cornerstone Heritage Range Lime Mortars and Renders

Cornerstone Heritage Mortar & Render

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A multipurpose NHL-free mortar with a high free lime content to replicate historic mortars.

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Cornerstone Marine Mix Marine Range Mortar

Cornerstone Marine Mix Mortar

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A fast-setting mortar for tidal zones, submerged areas or applications in contact with water.
From £14.6 £17.52 Inc VAT
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Cornerstone Newbuild Lime Mortars and Renders

Cornerstone Newbuild Mortar & Render

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A flexible, low-carbon lime mortar, render and plaster for modern or new build construction.
From £13.35 £16.02 Inc VAT
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Cornerstone Roofline Medium Mortar

Cornerstone Roofline Medium Mortar

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A fast-setting mortar for above the roofline, including hip tiles or the bedding ridge.
£15.55 £18.66 Inc VAT
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Cornerstone Performance Scantle Mix Mortar Bag

Cornerstone Scantle Mix Mortar

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A fibered mortar with an early set and bond for bedding natural slate or roofing materials.
£16.33 £19.60 Inc VAT
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Cornerstone Performance Tanking Render

Cornerstone Tanking Render

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A fast-setting, waterproof and sulphate-resistant render for internal areas exposed to water.
£19.81 £23.77 Inc VAT
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Cornerstone Performance Winter Mix Lime Mortar

Cornerstone Wintermix Mortar & Render

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A multipurpose mortar for cold climates requiring rapid strength to resist frost damage.
£15.18 £18.22 Inc VAT
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Cornerstone Performance Woodlath Render

Cornerstone Wood Lath Render

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A flexible fast-setting fibred mortar to help reduce slump and speed up application on lath.
£16.76 £20.11 Inc VAT
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Adaptavate Universal Multipurpose Breathable Plaster

Adaptavate Breathaplasta Universal

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A quick-setting plaster for improved moisture regulation and thermal and acoustic insulation.
£20.75 £24.90 Inc VAT
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Adaptavate Breathaplasta Smooth Finishing Plaster

Adaptavate Breathaplasta Smooth

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A breathable fine finishing plaster, ideal for achieving a smooth or fine polished finish.
£22.75 £27.30 Inc VAT
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Why use lime mortars?

Lime mortar is a traditional building material made from a mixture of lime, sand and water that has been used for millennia worldwide. Historically in the UK, it’s not uncommon to find masonry buildings constructed with stone, brick, or cob were built with lime mortars.

Known for its breathability, flexibility and durability, lime mortar has long played a critical role in the restoration and conservation of solid-walled buildings, where inappropriate materials can lead to damage that can be difficult to repair or even irreversible.

Unlike modern cavity wall construction, which features an outer layer and air gap designed to keep out moisture, solid-walled buildings require breathable materials to manage the moisture always present within the building fabric. As a result, cement-based mortars are unsuitable for these buildings as they are impermeable, often trapping moisture within the structure instead of allowing it to move or be released. As a result, common issues often found in historic to early 20th-century buildings arise, such as condensation, damp, mould, decay or masonry degradation as the moisture forces its way through the porous stone or brickwork to escape.

Further, traditional buildings often move and settle, which the brittle and rigid cement mortar can’t accommodate, creating additional stresses to the structure due to their incompatibility with soft brick or stone. The result can be the spalling of the masonry or cracking of the mortar itself. On the other hand, lime mortars are softer, flexible and porous, making them a compatible and sympathetic material that is both permeable and capable of accommodating movement and protecting the long-term health of the building fabric and masonry.

While lime mortars and their terminology may seem like a labyrinth compared to cement, there are two main categories of lime mortar to consider for most projects.

There are two main categories of lime mortar, known as Hydraulic and Non-Hydraulic lime mortars. These categories differ primarily in their setting process and applications. Hydraulic lime mortars contain impurities that enable them to set through a chemical reaction with water, allowing them to harden even underwater or in damp conditions, making them suitable for environments continuously exposed to moisture. We stock a range of dry ready mixed lime mortars made with hydraulic limes, including natural hydraulic lime.

On the other hand, non-hydraulic lime mortars harden through a carbonation process, which involves reacting with carbon dioxide in the air; this process also requires damp conditions and takes longer, but they end up as weaker more flexible materials, making them ideal for interior and historic restoration work where breathability and flexibility are crucial. We stock a range of non-hydraulic lime putty mortars, renders and plasters.

Today many are discovering that the properties of lime mortar can also benefit standard cavity wall construction. Lime mortars can assist with moderating humidity, reducing energy demand, and supporting more sustainable building practices by managing moisture and accommodating building movement, which, most importantly, helps to create longer-lasting and healthier buildings.

Our extensive selection of premixed lime mortars features a range of solutions for building conservation, renovation or modern new build construction. Need help with choosing before you buy? Our in-house expert team can help advise on suitable lime mortars for your next building or pointing project. Buy online or open a trade account with convenient local and nationwide delivery available.

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Need support? Get in touch with the team.

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FAQs

Lime mortar is a versatile material that is used in a wide range of applications. For historic to early 20th-century buildings with solid walls and no cavity, lime mortar is strongly advised to assist with managing moisture within the building fabric. Lime mortar can also be used in new build applications with a cavity. However, these are typically stronger limes with hydraulic properties. We stock the Cornerstone New Build Range, explicitly designed for new build construction.

If you are involved with or own a traditional solid wall building, you’ll likely require a renovation that requires compatible and sympathetic materials, such as lime mortar. Many names are used for lime, making it a topic that can be confusing or intimidating. To keep it simple, there are two main categories of lime mortar, primarily distinguished by the way they set. Limes that harden through a chemical process called hydration are known as Hydraulic Lime Mortars. These can include Natural Hydraulic Lime, Formulated Lime or Hydraulic Lime. Limes that have no chemical set and rely on carbonation are known as Non-Hydraulic Lime Mortars. These can include Lime Putty, CL90 Quicklime or CL90 Hydrated Lime.

Lime and cement are both excellent materials; one is not ‘better’ than the other. Rather, they are two binders used in different applications and building methods. Lime mortar is more appropriate for heritage and conservation projects than its cement counterpart and has long played an essential role in repairing and restoring solid-walled buildings.

There is no ‘best’ or ‘one size fits all’ mix for lime mortar. We always advise that each project is unique, and the mix should be application specific. Another option instead of mixing on-site is to use a premixed lime mortar. When choosing a premixed lime mortar, review the features and application guidance, as these materials are often specially designed for performance in particular applications.

Lime mortar can help better manage moisture problems, but to claim it stops damp is an overstatement. Lime mortars allow moisture to move in and out of solid wall construction, helping to reduce moisture build-up within the building fabric by better managing internal condensation and reducing moisture penetration from the external environment. Remember that there are many causes of damp, so while using a lime mortar might be beneficial, determining the cause of the damp and considering the options to correct it is the best first step.

Using a breathable lime mortar supports moisture to travel and escape from the masonry joints instead of the masonry itself, acting as a sacrificial element to help preserve the stone or brickwork. When stone or brick walls are paired with a rigid non-breathable mortar, the wall’s ability to diffuse moisture becomes compromised. Since this moisture can’t escape through the mortar in the joints, it forces its way through the porous stone or brickwork, which can cause masonry degradation or decay.