Lime Green's Prompt Mortar is a pre-mixed, fast-setting lime-based mortar for building, pointing, and rendering. It is a dry, pre-mixed mortar made with natural hydraulic lime and Prompt Roman cement.
Key Benefits
- Vapour-permeable, allowing breathability.
- Low shrinkage reduces the formation of cracks.
- Offers excellent adhesion and preserves the mortar’s low modulus of elasticity, which enhances resistance on soft supports.
- The natural light ochre colour provides a warm appearance.
- Sets quickly, enabling work to proceed even in challenging conditions.
- Available in 25KG bags
Coverage
- Repointing: 20kg m² stonework; 7kg m² brickwork.
- Per 1m3 of wet mortar to 1200-1800 bricks.
- If rendering, one 25 kg bag will cover 1.25-1.4 m2 at a 10mm thickness.
Surface Preparation
Before starting pointing or building, ensure you clean and remove all dust and loose materials from joints and masonry. Additionally, adequately dampen dry or high-suction surfaces to improve adhesion.*
Mixing
- Gradually add 25 kg of Lime Green Natural mortar into a drum mixer.
- Incorporate only 4 to 5 litres of clean water, pouring slowly as the mixture blends, using just enough water to achieve optimal workability.
- Mix thoroughly for 3 to 10 minutes.
- Note: This mixture cannot be reworked.
Application
Pointing and building mortars should be completed on the same day or the following day during cooler periods. Lime mortars, which require longer curing times than cement mortars, are applied using similar methods and principles.
When pointing or constructing hard, impervious masonry, or during damp, cool weather, lime mortars may take several weeks to fully resist frost. Avoid using lime mortars in temperatures below 5°C or above 30°C for optimal results.
Curing
Prompt Lime mortar sets quickly; however, like hydraulic lime, its strength and long-term durability develop over months rather than days. Proper curing is essential for success.
Protect the mortar from drying winds, strong sunlight, rain, and frost. During warm weather, lightly mist the mortar with water after application, then cover it with damp hessian sheets. In cold weather, shield fresh mortar with protective sheeting to prevent frost damage.
Downloads
- Technical Datasheet (PDF)
- Safety Datasheet (PDF)
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* - Trials should be undertaken on old surfaces & backgrounds to ensure compatibility. Lime mortars and plasters do not set or perform like gypsum or cement-based materials.
