Roundtower Fine Surface Filler is a dry, ready-mixed powder filler, specially designed for fine crack repairs and surface smoothing on lime or cement plaster backgrounds. This breathable filler is ideal for heritage and conservation work, offering fast setting, early sanding, and vapour permeability.
✔️ Colour: Light tan once set
✔️ Set Time: ~45–60 minutes
✔️ Application Areas: Lime or cement walls and ceilings
✔️ Breathable: Vapour permeable—ideal for solid-wall buildings
✔️ Pack Sizes: 1kg and 4kg paper bags
✔️ Free From: Synthetic pigments, polymers, and modern additives
Ideal For
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Filling hairline cracks, minor imperfections, or surface blemishes in lime plasters or renders
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Interior lime plaster walls and ceilings where breathable materials are essential
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Projects requiring a fast-set, sandable filler compatible with traditional construction materials
Application Instructions
Preparation
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Ensure surfaces are clean, dry, and dust-free
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For fine cracks, chase out slightly before application
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Dampen absorbent backgrounds to prevent premature drying; minimal dampening for dense surfaces
Mixing
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Mix with clean potable water to a slightly wetter-than-toothpaste consistency
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Avoid over-watering and mix gently to reduce airborne dust
Application
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Apply with a spatula or flat-edged trowel, pressing firmly into the crack
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Work diagonally across the fissure in both directions and slightly over-fill
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Allow to dry for 1–2 hours, depending on background suction
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Once dry, sand back level to the surface
Aftercare
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Mist lightly 2–3 times per day for 2–3 days to control curing
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In cases of shrinkage on high-suction backgrounds, reapply within 48 hours
Painting
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Filler carbonates over time, remaining alkaline for ~5 weeks
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Compatible with limewash and lime paints after 1 week
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Avoid synthetic paints until carbonation is complete
Roundtower Fine Surface Filler offers a conservation-appropriate solution for breathable, fine crack repairs where durability, ease of application, and heritage compatibility are key.
