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Natural Hydraulic Lime 3.5 - 2 Gallons


Calcidur® NHL 3.5


CALCIDUR ® is a Natural Hydraulic Lime EN 459-1 - NHL 3.5 CALCIDUR ® is produced from heating limestone in a shaft kiln. Natural Hydraulic Limes are made today in much the same way as they have been for centuries. Natural Hydraulic Limes have unique qualities that have been tested by time and cannot be equaled.


Because of their composition and performance characteristics, Natural Hydraulic Limes are the ideal product for a wide range of applications including building, pointing, render and plaster for the conservation, restoration and repeat of historic buildings. There is nothing more sustainable than successfully re-using the buildings we have. Conservation of the built heritage helps to reduce the use of precious resources, maintains the built environment and secures local heritage and traditions for the future generations.

Technical Data

Product Brochure

Mixing Ratio

1 part NHL to 2 part sand minimum

1 part NHL to 3.5 part sand maximum


CALCIDUR® NHL 3.5 is a natural hydraulic lime acc. to EN 459-1. It is produced through burning and staking a specifically selected shell limestone. The stabilizing process of CALCIDUR® NHL 3.5 is effected through carbonation and hydraulic hardening. CALCIDUR ® NHL 3.5 is free from cement!


• historic, cement- and gypsum-free natural hydraulic binder

• high sulfate resistance

• low-tension hardening process

• very good subsequent hardening properties

• no penetration of damaging salts into the masonry

• high elasticity and water retention capacity in mortar produced

• very good side adhesion at stone

• low elasticity module


For the production of plaster- and brick mortar in ecological,biological building construction, in the restoration and preservation of historic buildings.


Dry, if possible on wooden shelves and protected against draft.

Technical data

Bulk density: approx. 0.55 kg/dm3

free CaO: approx. 32%

SO3: approx. 0.4 %

Compression strength ( acc. to EN 459-2):

28 days: approx. 4.8 N/mm2

6 months: approx. 8.5 N/mm2

12 months: approx. 10.5 N/mm2

Safety instructions

CALCIDUR ® NHL 3.5 reacts strongly alkaline with water, thus: Protect skin and eyes, rinse thoroughly with water in case of contact, immediately contact doctor in case of eye contact.

Quality-monitored production

CALCIDUR® NHL 3.5 is continuously tested in our plant laboratory within the scope of our in-house monitoring with respect to the fulfilment of composition and properties. This will ensure a uniform quality of the product. CALCIDUR ® NHL 3.5 has the quality certificate „Building lime“ and is certified acc. to EN 459-1.


Ask a Question
  • Is this product ready to use or does sand need added?

    Yes, the "Natural Hydraulic Lime" products all need sand added. 

    Mixing Ratio
    1 part NHL to 2 part sand minimum
    1 part NHL to 3.5 part sand maximum

    The ready to use version of this is called "Historic Pointing Mortar" and those can be found here

  • I have a historic house from 1812 and have fireplace bricks that need to be re-mortared with a lime based product. Please advise if this product is appropriate for the job. Thank you.

    There are 3 different NHL products. NHL 2 is softest, NHL 3.5 is mid range, and NHL 5 is hardest. 
    If it is going to be exposed to heat I would recommend the hardest of the three, the NHL 5.

  • Can I mix this mortar with crushed marbel to patch hair line crack

    Yes.  Whiting powder would be another option, it is an extremely fine marble.