Roundtower NHL 2 is a feebly hydraulic lime binder ideal for internal lime plastering, external renders on soft masonry, and fine pointing or bedding mortars in traditional and breathable construction. Known for its workability, bright colour, and high vapour permeability, Roundtower NHL 2 is trusted by professionals across Ireland for both conservation and eco-building applications.
Manufactured to EN 459-1 standards, this lime is produced from a single, high-purity limestone deposit and contains no additives, ensuring full compatibility with historic masonry and sustainable new-build techniques.
Key Benefits
✅ Highly Breathable – Prevents trapped moisture, supporting healthy solid wall performance.
✅ High Whiteness (Y = 70) – Excellent for colour-sensitive plasters and limewashes.
✅ Eco-Friendly – Lime reabsorbs CO₂ during carbonation and supports low-impact building.
✅ Soft, Flexible Set – Ideal for softer substrates and buildings that experience minor movement.
✅ Self-Healing Capability – Free lime content allows micro-crack repair over time.
✅ Excellent Workability – High levels of free lime ensure a 'fatty' mix.
Applications
🔹 Internal Lime Plastering – Scratch, float, and finish coats over masonry or lath.
🔹 External Lime Renders – Where masonry is soft and breathability is essential.
🔹 Pointing & Bedding Mortars – For conservation repairs, especially in soft brick or stone.
🔹 Limewash & Finishes – High whiteness supports bright, consistent surface finishes.
🔹 Eco-Renovation & Heritage Repair – Compatible with traditional and breathable wall systems.
Technical Specifications
| Property | Value |
|---|---|
| Compressive Strength (28 days) | 4.69 MPa |
| Free Lime Content | 41.1% |
| Whiteness (Y value) | 70 |
| Fineness at 90 μm | 3.8% retained |
| Fineness at 200 μm | 0.4% retained |
| Expansion | 0 mm |
| Bulk Density | 0.592 g/cm³ |
| Real Density | 2.55 g/cm³ |
| Blaine Surface Area | 13,097 cm²/g |
| SO₃ Content | 1.45% |
| Setting Time (initial) | 987 minutes (~16.5 hrs) |
| Free Water Content | 0.83% |
| Standard Compliance | EN 459-1 (NHL 2) |
| Packaging | 25 kg paper bags (56 per pallet) |
Handling & Storage Advice
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Use the minimum amount of water required for workability—excess water can cause cracking. Dampen substrates the day before and prior to application, allowing the surface water to be reabsorbed. Avoid rapid drying due to high temperatures, direct sunlight or strong winds by covering and curing with a light water mist as necessary.
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Apply in temperatures between 5°C and 30°C.
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Protect from frost, rain, and rapid drying during curing. We always advise following best practices for curing and protecting fresh lime mortars and renders from direct sunlight and wind using hessian sheeting, which acts as a barrier between the freshly applied lime and the environment.
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Store off the ground in a dry, ventilated area and use within 12 months of production date.
Why Choose Roundtower NHL 2?
Roundtower NHL 2 is Ireland’s most widely used feebly hydraulic lime, offering precision, purity, and full compatibility with traditional building materials. Whether you're plastering internally, pointing a protected structure, or preparing breathable mortars for restoration, Roundtower NHL 2 delivers the performance, consistency, and heritage integrity lime specialists require.
