Clay is a mixture of clay and sandy components that can be considered a natural mortar. It is made up of tiny platelet-shaped particles which, when mixed with water, slide over one another and become plastic. When the water evaporates, the platelets attract one another, creating a natural strength sufficient for many construction applications.
A large proportion of the building materials used each year go towards this purpose, above all in new builds, renovations and modernisation, which is known as building within existing structures.
Indoors, clay building materials are used in the form of bricks, mortars, base and finishing renders, and clay boards. All of them are governed by modern DIN standards. Other relevant uses are decorative coatings and skim coats.
In addition, load-bearing construction with clay is gaining ground: the new DIN 18940 standard governs the use of load-bearing earth blocks for buildings up to 13 metres tall (four storeys).
Clay is an almost inexhaustible raw material, present naturally in the soil. In the case of ClayTec, no specific pits are dug to extract it: use is made of secondary clay, a surface layer generated during the extraction of gravel and sand. A potential waste product that becomes a resource.
A large proportion of the planet’s soils contain clay. It is an abundant natural resource which, if it were not used, would end up discarded. ClayTec uses materials that are already available, avoiding the creation of additional impacts.
The raw materials used in ClayTec products come, for the most part, from the areas near their production centres.
This means very short transport routes, which translates into:
This approach favours a more favourable environmental profile for the final product.
Simplicity of composition is another advantage: many products are made with just three basic ingredients —clay, sand and straw— with no need for chemical additives.
This guarantees:
Clay is, today more than ever, a building material with a present and a future. Its versatility, sustainability and availability make it a real alternative for those looking to build in a healthier, more efficient way that shows greater respect for the surroundings.
Energy consumption in the manufacture of building materials represents one of the main sources of greenhouse gas emissions and largely determines their carbon footprint. Time is pressing: according to the Global Status Report for Buildings and Construction from the United Nations Environment Programme, the construction sector generates 40% of global CO₂ emissions.
In this context, natural building materials, such as clay, position themselves as a greener alternative. Some ClayTec products go even further: thanks to their content of plant fibres, they not only reduce emissions but also act as carbon sinks.
Natural clay mortar and other clay materials can be manufactured, stored and applied with no need for industrial drying. The moisture content of the raw material —what we know as damp earth— is retained, keeping energy consumption to a minimum throughout the process.
Mixing clay with sand and straw can be done using electric motors powered by renewable energy, such as solar power, which makes this solution one of the cleanest and most sustainable on the market.
In cases where the clay mortar needs to be dried —depending on the type of machinery or application method—, this process can be carried out at low temperatures. Unlike materials that require firing or intensive heat treatments, clay does not need high temperatures to harden.
In addition, this drying can be carried out in the open air or with solar energy, avoiding the use of fossil energy and significantly reducing the carbon footprint of the production process.
One of the most decisive factors in achieving sustainable construction is the recovery potential of the materials used. Unlike many mineral materials which, after their service life, can only be crushed for secondary uses (which is technically downcycling), clay-based building materials can be directly reused or recycled, keeping their quality and properties.
Clay-based building materials bond with water, which means that even after decades of use they can be rehydrated, reshaped or reused. This water solubility gives them a unique recovery potential and makes them ideal products for a true C2C circular economy (cradle to cradle).
In this sense, ClayTec clay products make it possible to build with no waste. The reversibility of clay-based building systems is one of their greatest advantages compared with other materials.
Unlike traditional mineral binders —such as cement—, which require intensive firing processes, clay hardens simply by drying. There is no combustion or destructive chemical transformation: clay keeps its structure and, as it is not altered, it can be returned to its initial state simply by adding water.
This avoids the energy expenditure of the typical cycle of calcination, grinding and fresh chemical setting, making clay a truly low-emission option.
Clay is a completely recyclable building material with great versatility. Not only can it be directly reused, but it can also be turned into other compatible building materials. For example, a fat clay mortar can be turned into a lean one by adding sand or recycled aggregates, or a compact clay board can be prepared from a dry mortar.
This cross-compatibility makes it possible to adapt the material to new functions and projects without generating waste. If the remnants are recovered dry, you can even obtain a reusable pre-mix ready to apply.
Another great advantage of clay is that it allows completely reversible connections. A clay render can be removed with water without damaging the base surface; bricks laid with clay mortar can be dismantled and reused, something that does not happen with cement mortars.
In addition, even the finest components, such as sand, can be separated and recovered after decades of use. This pure separability makes it possible not only to reuse the clay but also to facilitate the recovery of other materials, promoting circularity across the whole building system.
Clay building materials stand out not only for their sustainability but also for their health-beneficial properties. In a context where we spend more than 80% of our time indoors, a healthy indoor climate is a necessity, not a luxury.
Clay has the ability to absorb water vapour from the air and release it when the air is dry, helping to maintain an optimal relative humidity. This hygroscopic quality is due to its structure of microplatelets with an enormous active internal surface.
Another crucial advantage is its ability to act as a natural filter: it holds back and neutralises pollutants and odours, helping to improve indoor air quality. This characteristic is especially important for people with allergies, asthma or multiple chemical sensitivity.
In addition, its porous surface, open to diffusion, allows a constant exchange with the surroundings, reducing the risk of mould forming. Thanks to this, clay is an ideal ally for creating healthier, more breathable homes and spaces.
The thermal mass of clay materials acts as a heat store, regulating indoor temperatures throughout the year. In summer, it cools spaces, and in winter it retains heat for longer.
This ability to even out thermal fluctuations makes it possible to create a thermally stable environment, reducing the need for artificial climate control and improving comfort naturally.
All of this is achieved with no additional energy consumption, and with no complex systems. It is a perfect example of what is known as effective “low tech”.
Indoor acoustics also directly influence the sense of wellbeing. Clay building boards make it possible to build dry walls with excellent acoustic insulation, reducing the spread of noise between rooms.
In addition, clay surfaces reflect less noise than rigid materials such as concrete, helping to create quieter, more pleasant spaces.
Clay is also an excellent support for radiant wall heating and cooling systems. Its natural diffusion capacity and its thermal mass allow a uniform distribution of heat.
These systems work with a low flow temperature, which markedly increases the energy efficiency of heat pumps and reduces total consumption. The result: thermal comfort with minimal environmental impact.
For centuries, clay has been a key material in traditional construction in almost every region of the world. This natural resource has been part of walls, infills, ceilings, renders and interior finishes, and it is still present today in a great many historic buildings.
In many cases, its use is hidden from plain sight, for example as ceiling infill or behind modern coverings. Building with raw earth has been fundamental to erecting homes, administrative buildings, warehouses, barns and even religious buildings, combining function, low environmental impact and durability.
For more than four decades, ClayTec has worked intensively in the field of architectural heritage conservation, especially in the restoration of timber-framed houses. Its experience and commitment to respectful restoration earned it the prestigious German Monument Protection Prize in 1997, in recognition of its work.
Thanks to its specialisation, ClayTec has developed a technical, authentic catalogue for the renovation of historic structures with clay, including specific solutions for renders, infills, insulation and finishes, always with the utmost respect for the original materials and techniques.
The restoration of timber structures requires compatible, stable and durable materials. ClayTec products, such as raw clay bricks and specific infill mortars, have been used for decades in successful conservation projects, proving their effectiveness both technically and aesthetically.
For exterior façades, the company offers bespoke lime renders, while for interiors it proposes complete solutions of thermal insulation and clay renders that respect the traditional aesthetic and improve thermal and acoustic comfort.
In addition, there are suitable products for renovating ceilings and horizontal elements in timber-framed houses, ensuring cohesion between the old building elements and the current solutions.
In many buildings of historic value, conserving the original façade with exposed timber framing is a legal or heritage requirement. In these cases, interior insulation becomes the best alternative for improving energy efficiency without compromising the exterior appearance.
ClayTec offers various interior insulation techniques designed specifically for this type of structure. These solutions are safe, effective and error-tolerant, both in planning and in execution. In addition, their hygrothermal behaviour helps regulate humidity, which extends the service life of the wood and prevents common defects in poorly insulated buildings.
A notable advantage of interior insulation is its ability to heat spaces quickly, something especially useful in traditional homes. It also integrates perfectly with wall surface heating systems, providing uniform, natural comfort.
The restoration of historic buildings must be done with the utmost care, always seeking solutions that are both effective and reversible and respectful of the original building. ClayTec clay products respond perfectly to this need.
Because clay is soluble in water, building elements can be dismantled, readapted or removed without damaging the structure or altering its original characteristics. This is especially valuable in interventions where reversibility is a requirement, since it allows work to be carried out with flexibility and precision on sensitive elements.
In addition, the malleable nature of clay makes it possible to adapt to the particularities of each building: the properties of the substrate, legal requirements, compatibility with existing materials and so on. This versatility makes clay one of the best options for heritage restoration.
ClayTec not only offers clay-based building materials but also provides architects, technicians and restorers with a comprehensive approach to the conservation of built heritage. Its products and solutions are designed to improve energy efficiency, guarantee indoor comfort and respect to the utmost the historic value of each property.
The combination of effective insulation, technical compatibility and low environmental impact makes ClayTec products indispensable allies in interventions on protected buildings, traditional houses or historic monuments.
In short, renovating with clay is today more than ever a way of building with memory, responsibility and a future, keeping alive an age-old technique that continues to offer efficient, sustainable answers to contemporary challenges.
