Building Materials

Building Materials

Over the ages, builders have made use of the binding properties of lime to construct different types of structures: Roman temples, castles, cathedrals and bridges, etc. Today, lime-based mortars still form part of masonry and plaster mixes for building facades. Lime is also an ingredient in modern building materials such as aerated concrete and sand-lime bricks. These materials have excellent thermal, fire as well as acoustic insulating properties and are easy to work with, making them extremely popular. Limestone and clay are major components for building and construction products. Lhoist offers a wide range of aggregrates, ground and milled minerals specially formulated to be used as fillers and extenders.

Tradical® is the global Lhoist brand for construction products and services.

Mortars, renders and plasters

Wall construction involves the positioning and fixing of bricks and blocks. Walls must cope with loading, deformation due to climactic conditions, vibrations and more. Tradical® enables mortars, renders and plasters to absorb the deformations of load-bearing structures. It also improves their long-term behavior and provides protection by:

  • tolerating thermal cycling
  • withstanding air and water pollution
  • retaining water-proofing capabilities
  • allowing vapor permeability.

Excellent workability makes application straightforward. Extended pot life provides flexibility in application practices to minimize waste.

The combination of Tradical®H hydrated lime (Tradical® type "S" in the US) and tartaric acid controls the reactivity and hardening speed of FGD (flue gas desulfurization) gypsum in a cost-effective way. This is the only means of ensuring the workability of gypsum for modern renders and plasters.

Decorative finishes made with Tradical® products are attractive, durable and easy to maintain. They offer a naturally soft and eye-catching experience that differentiates a building’s appearance. They are also hypo-allergenic. Color variation possibilities are limitless.

Sand-lime bricks (SLB)

We produce a special quality of lime for calcium silicate (sand-lime) bricks that makes them especially simple to work with. Only natural raw materials are used; a mixture of ‘natural’ calcic lime, sand and water is pre-formed in presses. The result is hardened in autoclaves under steam pressure at temperatures between 160°C and 200°C. Lime and quartz sand react to give the bricks their compressive strength to bear high loads. Calcium silicate bricks also provide good sound-insulating properties.

Autoclaved aerated concrete (AAC)

Aerated concrete is made of lime, cement, sand, gypsum and water. These components are homogenized and aluminum powder is added. This acts as a gas-forming raising agent, producing a frothy mass which is cut with wires and hardened in autoclaves. Aerated concrete is an easy-to-use, light-weight building material. It offers excellent fire-resistance characteristics and demonstrates high thermal insulation performance.

We manufacture lime with the exact reactivity curves to fit the raw materials and processes required for aerated concrete.

Clay bricks and roofing tiles

Limestone is used in the manufacture of clay bodies such as bricks and tiles. It controls oxidation and offers slight changes in color and color patterns.   

Ceramics, tiles and sanitary ware

We deliver minerals that are essential to the production of ceramic goods, including sanitary ware, porcelain floor and wall tiles, porcelain figurines and other fired ceramic items. Ball clay is one of the two largest components of a ceramic body. It plays a critical role in the formation of ‘green strength’ or ‘plasticity’. It also serves to bond other components together and facilitates even firing in the kiln. Limestone is used as a fluxing agent and adds porosity in certain ceramic applications, such as the production of wall tiles.     

Cement and concrete (aggregates and fillers)

Our portfolio includes a wide range of aggregates as well as ground and milled minerals. We have developed limestone fillers specially formulated to be used as certified fillers and extenders. These enhance the properties of cement and fly ash in ready-mixed concrete, precast and manufactured concrete. In this way, we contribute to the development of ergonomic concretes that eliminate vibration and noise. Our refined minerals offer unique consistency in color and shape. Engineered Tradical® products are widely available and can be used as a cement additive to control hardening speed and concrete quality.

Fiber cement boards

Limestone serves as filler in fiber cement siding, cladding and backer boards. It adds stiffness and strength to the final formulation and is used by many high-end producers in place of more abrasive silica fillers. During fabrication and installation, limestone helps prevent the generation of nuisance silica dust.

Insulation materials

We develop special, environmentally-friendly binders for innovative applications that provide answers to societal concerns. Tradical® Hemcrete® is a unique, highly sustainable construction product that will certainly play a bigger role in the future of sustainable buildings, because it:

  • creates insulating walls and insulation layers in floors and roofs
  • locks in carbon dioxide (CO2)
  • is one of the best-value low-impact, sustainable and commercially viable materials
  • has a natural breathing capacity that makes it extremely suitable for refurbishment and restoration projects. 

Our bio-composite building material that incorporates Tradical® binders and sustainable aggregate delivers excellent thermal properties to create healthy living and working environments


Historical building restoration

Hydrated lime is ideal for the restoration of historical buildings as it was used by our ancestors. Its resistance to ageing can be seen in edifices around the world. Why is it best?

  • Lime absorbs carbon dioxide (CO2) contained in the ambient air, returning the active lime to its original stable rock-like crystal state.
  • Its compatibility with existing materials is fundamental to the durability of the refurbishment.
  • Mortars and plasters that include lime are flexible which limits the cracking risk of masonry blocks.
  • It protects the original structure from shear forces and damage.

Lhoist has industrialized the production of the lime putties originally used for traditional application. Tradical® SLS 45 is ready-to-use and storable and therefore extremely useful for restoration projects


Lhoist industrialized the production of highly concentrated milk of lime/lime slurry maintaining all the advantages of former putty lime and eliminating the significant quality variations seen in the past. Tradical® SLS45 NP is a raw material devised for paint formulations. Polymer free, it is perfect for solely mineral formulas. It creates no emissions. With a pH above 12, it also inhibits growth of bacteria, mold and fungi, with no addition of chemical biocides necessary.

Tradical® SLS45 NP represents a new generation of industrial lime putty for historical and modern constructions.

Asphalt roofing

Limestone acts as a filler in the production of asphalt-based roofing shingles, either fiberglass-cored or organic material-based. Consistent, high-calcium chemistry is crucial to the achievement of proper tear strength of the final product. The presence of magnesium or silica is considered deleterious. Particle size is strictly controlled to achieve stable viscosity and maximum loading and packing. Surface characteristics of the particles are also important to ensure that volatile oils are not absorbed by the filler, which would cause an alteration in viscosity.

Our fillers have proven to be extremely beneficial and have served the industry for more than 50 years. Limestone granules made from selected deposits and tightly-controlled production processes yield headlap granules with excellent bonding and opacity characteristics. We hold several patents for advanced roofing granules and fillers.