Natural Hydraulic Lime (NHL)

Explore the world of lime mortar and discover why it is the preferred choice for historical building restoration and new construction projects. Learn about the manufacturing process, applications, and benefits of this versatile material.

Manufacturing of Natural Hydraulic Lime

Natural hydraulic lime is manufactured by burning limestone that contains impurities such as clay and other minerals. This process produces a hydraulic binder that sets through a combination of chemical reactions. The resulting product is breathable, flexible, and durable, making it ideal for use in restoration projects.

Mixing and Application of Lime Mortar

Lime mortar is mixed by combining natural hydraulic lime with sand and water to create a workable mortar. It is then used for building and pointing stone and brickwork, allowing for gradual curing and bonding with the substrate. Lime mortar is preferred over cement in restoration projects due to its compatibility with historic materials and structures. lime is breathable, allowing the structure to expel moisture. 

Uses and Applications of Lime Mortar

Lime mortar is used in a variety of applications, including repointing of brickwork, plastering external walls, and plastering interior walls. Its breathability and flexibility make it suitable for historic buildings, as it expels  moisture and prevents damage from freeze-thaw cycles. Proper application and maintenance of lime mortar are essential for the long-term preservation of historic structures.

Benefits of lime

  • Can be remixed
  • Breathable
  • Flexible
  • Environmentally beneficial
  • Compatible with historic materials
  • More aesthetically appealing 
  • Available in different strengths NHL 2, 3.5 and 5

working with lime

Depending on the job the materials needed will determine the ratio and strength used. Combine NHL, sand and water to create lime mortar. This product can be remixed, so you are not pressured to use a particular mix in the same day thus reducing waste.

After care

Lime requires care and attention once in the wall, hessian cloth is used to control the curing time of lime and to protect it from the elements. Wetting the hessian in dry warm weather, and adding extra layers in cold wet weather. Ultimately the longer its covered the better, but aim for 2 weeks minimum to allow the lime to cure naturally.

Ready to restore your future with lime mortar?

Contact us today to learn more about how our experienced team can help with your building and restoration projects.