Roundtower NHL 3.5 Fine is a dry pre-mixed lime mortar made with high-purity NHL 3.5 and 2mm kiln-dried sand, specifically designed for pointing, bedding, rendering, and general masonry work. Blended in a controlled environment with selected additives, CLD35 offers improved workability, extended open time, and reduced shrinkage risk, while maintaining the core virtues of a traditional, breathable NHL-based lime mortar.
Supplied ready to use—just add clean water—this mortar is ideal for heritage restoration, solid wall construction, and projects where consistency and convenience are essential.
Key Benefits
✅ Factory Pre-Mixed – Guaranteed 2:5 NHL to sand ratio with consistent quality in every bag.
✅ Improved Workability – Easy to apply, float, or finish; suitable for hand or mechanical application.
✅ Extended Open Time – Minimum 8 hours working time once mixed, longer in cold conditions.
✅ No Cement Added – 100% natural hydraulic lime mortar for breathable, conservation-grade work.
✅ Low Shrinkage Risk – Carefully formulated to minimise cracking, especially in render applications.
✅ Eco-Friendly & Recyclable Packaging – Supplied in 25kg recyclable paper bags with polythene liner.
Applications
🔹 Pointing – Suitable for repointing stone, brick, and block in new or historic construction.
🔹 Bedding Mortars – Used for laying brick, block, or stone where a breathable mortar is required.
🔹 Fine Lime Renders (Top Coats) – Provides a smooth, consistent finish when applied at 6–10mm.
🔹 General Masonry Repairs – Compatible with traditional backgrounds and substrates.
🔹 Conservation & Listed Buildings – Meets best practice standards for breathable masonry restoration.
Technical Performance & Coverage
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Binder: Roundtower Natural Hydraulic Lime (NHL 3.5)
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Mix Ratio: 2:5 (lime to sand)
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Sand Size: Up to 2 mm
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Compressive Strength: Appropriate for medium-strength applications (NHL 3.5 binder)
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Coverage (Rendering): Approx. 1.4 m² at 10mm thickness per 25kg bag
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Coverage (Pointing): Approx. 25 bricks per 25kg bag
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Yield: Approx. 13.5 litres of mortar per 25kg bag
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Open Time (after mixing): Minimum 8 hours
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Packaging: 25 kg polythene-lined paper bags (40 bags per 1T pallet)
Mixing Guidance
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Add 4–5 litres of clean potable water per 25kg bag.
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Best results: Add 60–70% of the water first, then gradually incorporate the dry mix. Adjust water to desired consistency.
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Mix for 5–10 minutes. Do not overmix.
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Quench the mortar by letting it sit for 10–20 minutes after mixing, then remix briefly before use.
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If needed, add small amounts of water to maintain workability during use.
Why Choose Roundtower NHL 3.5 Fine ?
Roundtower NHL 3.5 Fine combines the performance of a traditional lime mortar with the convenience and consistency of a ready-to-use product. Whether you're pointing a historic wall, rendering a breathable façade, or bedding stonework, this product ensures conservation-appropriate results with modern site efficiency.
