Natural Hydraulic Lime (NHL)

Natural hydraulic lime is widely used across heritage restoration and modern eco builds where moisture management matters. Here at bio space, we supply natural hydraulic lime suited for lime render, lime plaster and limecrete helping maintain vapour permeability while still delivering a reliable set and strength. Whether you are a contractor or sourcing for a renovation, consistent quality and supply matters, which is why we offer trade-friendly options alongside materials that pair seamlessly with natural insulation and breathable systems. If you are looking for natural hydraulic lime suppliers who understand full system compatibility, this range is built to support long term performance.

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Frequently asked questions
What is natural hydraulic lime and how is it different from non-hydraulic lime?

Natural hydraulic lime (NHL) sets through a reaction with water as well as air, giving it a faster and harder cure than non-hydraulic lime. This makes it particularly suitable for external renders, structural work and areas exposed to the weather.
What do NHL 2, NHL 3.5, and NHL 5 mean?

These classifications refer to the compressive strength of the lime after 28 days, measured in MPa. NHL 2 is softer and more breathable for internal or heritage work, NHL 3.5 is the most commonly used for general building, and NHL 5 is stronger for exposed applications.
Why is natural hydraulic lime important for breathable construction?

Natural hydraulic lime allows moisture to pass through the building fabric, reducing the risk of trapped moisture and condensation. This helps prevent issues like damp, mould and material decay, particularly when used alongside breathable insulation systems such as woodfibre boards.
Can natural hydraulic lime be used with modern insulation materials?

Yes, but it performs best when paired with one of our vapour-open natural insulation systems such as woodfibre insulation, cork, or hemp-based materials. Using it with non-breathable insulation can compromise the overall system by trapping moisture within the structure.
Do you offer bulk supply for natural hydraulic lime?

Yes, bulk purchasing is available for larger projects, making it suitable for contractors, developers and trade buyers. Reliable supply at scale is key for consistent application, especially across multi-phase builds or ongoing site work.