Hydraulic lime is an ancient binder used in the construction industry for masonry and plastering. It is made from quality natural stone and naturally has many positive building-physical properties.
The breathable nature of hydraulic lime ensures a healthy indoor climate.
Hydraulic lime is also elastic in nature: it can partially repair itself in case of cracking.
Currently, hydraulic lime is widely used in heritage restorations. However, we notice that the use of natural lime is regaining popularity in modern housing construction.
The purity, aesthetic and acoustic added value of lime certainly contribute to this renewed attention.
And rightly so!
Unilit hydraulic lime is made primarily from pure limestone.
All ingredients are of natural origin.
No cement, synthetic resins or plastic adhesives are added.
As there are no longer any Belgian production facilities for hydraulic lime, our products come by train from Italy.
The production process
- Limestone is mined in opencast quarries.
- We only work with Marne stone, a natural stone rich in minerals.
- Burning the limestone: for a week, the natural stone is slowly burnt at a temperature of 800 to 1100°C until it is almost pulverized.
- Quenching the burnt limestone: after burning, the natural stone is highly reactive (exothermic) and needs to be cooled down or brought to rest. This is called “quenching”
- The unique feature of the extinguishing process of Unilit products is “dry quenching”. After the burning process, the hot natural stone is given at least several months to come to rest in the open air. No water is involved.
- After that rest period, the lime is bagged up and transported to Belgium by train.
The use of lime in construction and as a finish goes back to the time of the Egyptians.
- Hydraulic lime is a very versatile product. It can be used in construction as well as in floor and wall finishes.
- Many historical buildings and monuments are built of hydraulic lime and do not tolerate repairs with cement-based products or synthetic resins when restored.
- Hydraulic lime was used for the construction and restoration of e.g. the Antwerp Cathedral, Thiepval Memorial Common Wealth Wargraves, the Begijnhof Hoogstraten, etc.
- Unilit hydraulic lime is composed of pure natural materials.
- No VOCs or harmful substances are present in the product.
- The full life cycle impact of hydraulic lime on CO2 emissions is very acceptable: the emissions released during combustion are also partly offset by the carbonation process (= curing of free lime, by binding with CO2).
- In its final stage, hydraulic lime can serve as a soil conditioner for farmers or as a filler for new lime applications.
Hydraulic lime has a lot of healthy qualitative properties:
- Moisture regulating
- Antibacterial and fungicidal
- Does not rot
- Very long lifespan (circular: lime becomes limestone again by absorbing C02)
- Allows reuse of facing bricks
- Timeless – aesthetic
- During production, lime (800-1250°C) uses less energy than cement ( >1400°C)
- Lifelong absorption of CO2
- End-of-life ≠ waste
- In facade applications: no expansion joints are required and no salt efflorescence on bricks
Very cheap mass products like cement and plaster at dumping prices have pushed hydraulic lime away from the market as a healthy alternative.
However, with an increasing interest in a healthy indoor environment (because of the quarantines during the corona epidemic) and growing concerns about the environmental impact of cement, hydraulic lime as a binder is regaining popularity among architects and building owners.