Building Construction

Building materials: new!

Less carbon and higher thermal performance are the trends in building materials. Discovery of some innovations that will be introduced in the coming years.

Building materials are changing. Discreet and invisible once covered by the plasters, they nevertheless actively participate in the heat balance of the house. And unlike the finishing work, once installed, it is impossible to replace them. Hence the importance of making the right choice from the design stage.

What should we base ourselves on? “At the thermal level, the optimum is reached and the thermal regulations will no longer change. Today, it is the environmental side that takes precedence. Industrialists have already done a lot of work on this aspect by significantly reducing their emissions. This is really what will be at stake in the coming years,” says Olivier Dupont, manager of the products & works department at the Centre technique de matériaux naturels de construction.

To meet current and future requirements of the Thermal Regulations, some new generation materials incorporate high-performance insulation, others simply abandon traditional aggregates for biosourced materials. Finally, some are concerned about a public health problem and protect people sensitive to radio frequencies. The objectives are always the same: to improve their thermal performance and daily comfort while reducing the house’s carbon footprint. Objectives met!

Building materials: concrete block

Often considered rudimentary, today’s concrete blocks have become a “high-tech” material. The most advanced ones are not only ground (the assembly joint is only one millimetre thick and glued) but they also incorporate very high-performance insulation such as Airium®. These new generation breeze blocks display simply exceptional thermal resistance! “We have replaced polystyrene, which has a bad carbon impact, with this Airium® foam developed by Lafarge. We produce two types of blocks with different geometries that have Rs from 1.12 m2k/W to 1.77 m2k/W. The most efficient block is made of pumice stone,” explains Jérôme de Mauroy, marketing and communication director at Fabemi. “Their density ranges from 10 to 8 blocks per square meter. »

The Airium® which gives all the thermal qualities to these blocks is a mineral foam. It extraordinarily strengthens their insulating capacity. One of the main characteristics of this innovation is its low cement density, up to six times lower than with conventional concrete, which makes it possible to trap a large volume of air in the dry state and to obtain thermal properties comparable to those of traditional insulation materials. Never seen before! This foam is totally inert, does not emit any VOCs and therefore poses no risk to occupants.

Building materials: clay brick

Terracotta brick is one of the oldest building materials. It has evolved over the centuries to become one of the most efficient materials on the market today. “We have made a lot of progress and the resistance of clay bricks has increased threefold in 20 years. The requirements of the thermal regulations will no longer evolve as much as with the RT 2012 and clay brick was the product that best met this requirement. This is also why nearly one out of two houses is built in terracotta brick, and today it is the environmental aspect that is new. Industrialists have already done a lot of work on this aspect by significantly reducing energy consumption (nearly 40% reduction in twenty years) and greenhouse gas emissions (-35% in the same period) in manufacturing. ” underlines Olivier Dupont,. And add “the classic 37.5 cm Monomur terracotta ® has a thermal resistance of 3.5 m2.K/W. It remains a niche market. Most sales are made with 20 cm bricks, which reach a resistance of 1.5 m2 K/W. This 20-foot thick brick frees up the living space, up to 3% of the surface area saved because less insulation is needed: this represents almost 4 m2 on an average house of 121 m2”.

Today, some manufacturers are further improving the material’s performance by filling the cells with high-performance rock wool. Not only does this type of block meet today’s requirements, it even exceeds them. In terms of performance, we are reaching levels that were unthinkable only a few years ago. For a thickness of 30 cm, these bricks display an R = 4.05 m2.K/W, for a thickness of 36 a R = 4.88 m2.K/W and a R = 5.71 m2.K/W for a thickness of 42 cm ! These blocks, like all factory ground bricks, stick together to the nearest millimetre to improve airtightness. From the outset, this type of block is eligible for the Bepos (Positive Energy Building), Effinergie+ labels. These blocks stick to the millimetre to improve airtightness. From the outset, this type of block is eligible for Bepos (Positive Energy Building) and Effinergie+ certifications.

On the installation side, the terracotta industry is always at the forefront of innovation. It was she who invented the thin-jointed ground blocks assembled with adhesive mortar. She has since developed dry laying. This application replaces the traditional mortar or thin joint with a bead of high-performance glue applied with a spray gun. As a result, the construction of the house requires virtually no water, there is less waste on site and construction times are reduced due to increased ease of installation. “According to the craftsmen who use this technique, this glued installation saves about 30 to 50% of the time required to prepare and clean the site,” concludes Olivier Dupont.

Building materials: the miscanthus block

Aggregates are a non-renewable raw material that is becoming scarce and must be preserved. However, concrete in general and concrete block in particular make it a major consumer. The solution to continue to produce quality blocks? They are made from a renewable raw material of plant origin. A successful bet with the miscanthus block.

It has the appearance, dimensions and weight of a conventional concrete block and yet it is biosourced. Miscanthus is a plant of Chinese origin produced in France which makes up 60% of its composition, instead of aggregates. Its main quality? It offers a good thermal resistance of R = 0.7 m2.K/W (compared to 0.2 for traditional blocks) totally in line with current and future thermal regulations (E+C- and future RBR 2020). It is about three times more insulating than conventional concrete block. Naturally, its mechanical qualities are beyond reproach.

This miscanthus carrier block also meets the requirements of acoustic comfort with a noise attenuation of 54 dB. In addition to its thermal and mechanical performance, its local manufacture and short distance transport further contribute to reducing the environmental footprint of buildings, one of the important objectives of RBR 2020. For its implementation, the masons remain on known ground. The installation is simple and traditional, and respects the working methods of the craftsmen masons.