At Roundtower Lime, we are proud to offer one of Ireland’s most comprehensive selections of non-hydraulic limes, ideal for traditional building techniques, historic restoration, and eco-conscious construction. Our range includes premium mature lime putty, expertly slaked and matured for a minimum of four months to ensure optimal workability, flexibility, and durability.
Unlike hydraulic limes, non-hydraulic lime (also known as lime putty or fat lime) sets slowly through carbonation — by absorbing carbon dioxide from the air. This slow-set process gives it superior breathability, excellent moisture buffering, and exceptional flexibility, making it the preferred binder for soft masonry, conservation pointing, internal fine plasters, lime washes, and heritage renders.
Why Choose Roundtower Non-Hydraulic Lime?
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Matured on-site for guaranteed quality
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Ideal for conservation and heritage work — approved by conservation officers across Ireland and the UK
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Unparalleled vapour permeability — ensures breathability and helps manage internal humidity levels
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Superior flexibility — accommodates building movement and reduces cracking
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Highly workable and plastic — excellent for pointing, plastering, and fine finishes
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Free from cement or additives — pure, traditional lime for true conservation compatibility
Our non-hydraulic lime is available as:
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Lime Putty – matured and ready to use for plastering, rendering, or limewash production
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Ready-Mixed Mortars – blended with natural sands for pointing, plastering, and fine renders
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Lime Skim Finishes – such as Heritage Lime Skim (CLM66), for smooth breathable internal finishing
Frequently Asked Questions (FAQ)
What is non-hydraulic lime?
A: Non-hydraulic lime is made by slaking quicklime with water to produce lime putty. It sets slowly by absorbing carbon dioxide from the air (carbonation), not by reacting with water.
When should I use non-hydraulic lime instead of hydraulic lime?
A: Non-hydraulic lime is ideal for internal work, protected external areas, or historic masonry where maximum breathability and flexibility are needed. It is especially suitable for soft brick, stone, or cob.
Can I use non-hydraulic lime externally?
A: Yes — but only in sheltered conditions. For exposed environments, Natural Hydraulic Lime (NHL) is generally more appropriate due to its faster set and water resistance.
What’s the shelf life of lime putty?
A: Lime putty has an unlimited shelf life when stored under water. In fact, the longer it matures, the better the performance.
Is non-hydraulic lime breathable?
A: Absolutely. It offers the highest vapour permeability of all lime types, making it ideal for regulating moisture in solid-walled buildings.
Can I paint over non-hydraulic lime plasters?
A: Yes, but only with breathable paints such as limewash or mineral silicate paints like Beeck Maxil Pro. Avoid modern acrylics or emulsions.
