Roundtower NHL 2 Coarse is a multi-purpose, dry ready-mixed lime mortar made with Natural Hydraulic Lime (NHL 2) and coarse kiln-dried sand, blended in a controlled factory setting. Supplied in a 2:5 mix ratio (lime to sand), this mortar is ideal for bedding, pointing, and base coats in render systems, especially where a softer, vapour-permeable mortar is needed for heritage or eco-building projects.
The formulation includes selected additives to enhance workability, open time, and durability, while retaining the essential breathable, cement-free qualities of a traditional lime mortar.
Key Benefits
✅ Feebly Hydraulic Strength (NHL 2) – Ideal for softer backgrounds and low-strength masonry.
✅ Pre-Mixed for Site Efficiency – Consistent 2:5 blend ensures reliability and saves time.
✅ Excellent Workability – Smooth handling with extended open and finishing time.
✅ Breathable & Compatible – Vapour-open and cement-free, suitable for conservation use.
✅ Low Shrinkage Risk – Carefully balanced mix reduces the chance of cracking in renders.
✅ Natural Appearance – Contains no pigments or colourants; colour may vary slightly due to natural sands.
Applications
🔹 Bedding Mortar – Suitable for soft brick, rubble stone, or low-strength block.
🔹 Pointing Mortar – Ideal for historic brick and stonework in protected or listed structures.
🔹 Coarse Base Coats – Can be used as a undercoat or finishcoat in lime render systems.
🔹 Breathable Solid Wall Construction – For conservation and natural building projects.
Coverage & Yield
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Render Coverage: Approx. 1.4 m² at 10 mm thickness per 25 kg bag
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Bedding Coverage: Approx. 25 bricks per bag
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Yield: Approx. 13.5 litres of mortar per 25 kg bag
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Water Addition: 4–5 litres per bag depending on application and desired consistency
Mixing & Application Guidance
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Recommended Method: Add 60–70% of total water to mixer, then dry mortar. Mix 5–10 minutes, add remaining water to adjust consistency.
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Quenching: Let stand for 10–20 minutes after mixing, then remix before use.
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Open Time: Minimum 8 hours once mixed – longer in cooler weather.
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Best Practice: Avoid over-wetting to reduce shrinkage risk. Always dampen highly absorbent substrates.
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Application Temperature: 8°C to 30°C. Protect from frost, rapid drying, or rain during curing.
Packaging & Storage
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Bag Size: 25 kg polythene-lined paper bags
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Pallet: 40 bags (1 tonne)
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Storage: Store dry, off the ground, and protected from damp or rain
Standards & Compliance
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Manufactured in line with BS EN 998-1:2016 (for renders and plasters)
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Conforms to BS EN 998-2:2016 (for masonry mortars)
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Produced under ISO 9001:2015 Factory Production Control
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CE-marked and 100% cement-free
Why Choose Roundtower NHL 2 Coarse ?
Roundtower NHL 2 Coarse offers a conservation-appropriate, highly breathable mortar with site-ready convenience. Whether pointing a vernacular stone wall, bedding masonry in a listed building, or applying a base coat to natural insulation, this mix provides the flexibility, vapour openness, and reliability required for traditional and sustainable construction.
