The article presents the results of a study of the properties of flax straw as a raw material and as a lightweight, environmentally-friendly insulation made of a two-component mixture of flax straw and liquid glass. The flax is considered to be renewable and is a 100% natural waste product of the agriculture industry, which may be widely used as sustainable building insulation after light modifications. The ratio mixes of the two-component eco-insulation of flax straw and liquid glass (Na2O(SiO2)) have been developed in terms of sustainability principles such as environmental friendliness and energy efficiency. We used thermal analysis to compare flax straw as a raw material, and a complex insulation made of flax straw demonstrated a slower decomposition of the composite and shorter peaks, which supports the concept of the transformation of flax straw with liquid glass to increase its fire resistance properties. The peaks of the loss of mass with the exothermal process were defined for both flax samples. The thermal conductivity coefficient of the material is around 0.085 W/m K, which permits its use as an effective insulation material for sustainable buildings.

The research suggests a production method of insulating composites created from lignocellulosic agricultural biomass with fungal mycelium as a binder agent and offers a deeper investigation of their thermophysical properties. Particularly, the samples were meticulously evaluated for density and thermal conductivity. The function was built on the suggestion by the authors regarding the thermal conductivity-weight ratio indicator. The metric was initially introduced to assess the correlation between these parameters and was also applied to qualitatively evaluate the biocomposite among other commonly used natural insulations. An applied polynomial trend analysis indicated that the most effective densities for the wheat, hemp, and flax, which were 60, 85, and 105 kg·m⁻³ respectively. It was determined that the optimal density for wheat and hemp composites corresponded to values of 0.28 and 0.20 W⁻¹·kg⁻¹·m⁴·K of the coefficient, respectively. These values were superior to those revealed in other common natural insulating materials, such as cork, cotton stalks, hempcrete, timber, etc. As a result, the proposed insulating material may offer numerous opportunities for application in industrial settings of civil engineering.

The focus of this study is on the hygrothermal and mechanical properties of the elaborated insulating composite based on flax straw. Flax straw is considered as an agricultural waste of organic origin, which has a high sorption capacity and a low thermal conductivity potential due to its natural porosity. Investigations on sorption moisture, thermal conductivity and mechanical properties under laboratory conditions have allowed us to develop a perspective building material suitable for use in ‘green’ construction, especially in rural areas, due to the relative accessibility of the base component. Liquid glass is proposed as a binder. The optimal composition of the filler and binder, sorption moisture, thermal conductivity and surface mapping of the proposed material were investigated. The thermal conductivity reached a minimum value of 0.0728 W m⁻¹ K⁻¹ at relative humidity of 50% during desorption, which is highly competitive to the values for conventional insulation materials on an organic basis. The binder was visually distributed evenly over the surface according to the SEM analysis. Corresponding to the spectral analysis by chemical elements, Na and SiO₂ in total showed 17.69% quantity volume on the composite surface of 2–5 μm in depth. Graphical Abstract

The article presents the results of a study involving the properties of flax and hemp-based lightweight concretes as well as the initial characteristics of different straw-based materials. A comparison of straw-based lightweight concretes with and without ordinary Portland cement (OPC) showed that hemp concrete has a 5.6 % higher strength at a 10% deformation, and at the same time, has a 13% greater thermal conductivity coefficient than flax concrete. The physical-chemical study based on a thermal analysis in an air environment has shown that the overall picture of thermal degradation for flax and hemp concretes is similar. Nevertheless, additional peaks of mass loss have been defined for flax concrete. The demonstrated exothermal process is a positive aspect, considering the life cycle of the material and the recycling stage. The paper proposes reference points for the development of new building materials based on straw.

Achieving carbon neutrality by 2050 is one of the European Union’s key priorities. Yet, the attitude of numerous politicians, of the professional community, and of society in general towards the threat posed by climate change is ambivalent. Arguments are frequently heard about the transition to a low-carbon economy that will be very costly, with increased unemployment, and that in reality climate change may not even be that severe. Added to this, there are human rights and freedoms, and in the case of architects and designers, the right to freedom of creation, to choice of materials, etc. The present article seeks to show that the issue of sustainable architecture and construction is not a whim, but an absolute necessity, and that true freedom lies in recognizing this fact and adapting our actions accordingly. However, even if we have the good intentions to adapt the needed actions, there is still the question of how to react in the right way, without causing myriad unwanted side-effects or being completely counterproductive. As there is not yet any comprehensive account of the history of energy-efficient and sustainable building and architecture, this paper has attempted to give a brief overview of developments in this field from a Central European perspective. Furthermore, the aim was to point out some conceptual mistakes that have been made in the past and that should be avoided.

According to the set of the expected outcomes from building sector elaborated during the latest COP26 summit, 100% of new buildings must be net-zero carbon in operation by 2030 and embodied carbon must be reduced by at least 40%, while by 2050 all new and existing assets must be net zero across the whole life cycle. In this regard, the basic challenge is the development, and integration in a building practice, new eco-friendly materials with a minimal environmental impact from raw source extraction to recycling of the final product after building demolition. Straw as a sort of agriculture waste is currently widely available in the EU market and has a significant potential to be implemented in sustainable design solutions in constructions. A new form of low-energy biological production and waste recycling is the vegetative growth of fibrous fungi (mycelium). Mycelium materials have several basic advantages over the traditional synthetic materials, including their low cost, density, and energy consumption as well as their biodegradability and low environmental impact. In the presented paper the composition of mycelium based straw insulation has been developed and tested in laboratory conditions. The principal physical and technical properties have been studied and analyzed in the context of its application in the construction industry. The process of samples producing is described in detail and adapted with the perspective of its industrialization.