The building industry produces more than 30% of the European Union's waste. To reduce this waste, buildings should be designed in line with the principles of the circular economy, so that the products and materials they contain can be removed and reused at the end of the building's life cycle. Therefore, a modular system has been designed, the load-bearing part of which is made up of prefabricated frames composed of plywood. To verify the actual reuse potential of the structure, an experiment was carried out in which a house was assembled and operated for one year. After dismantling the house, the reuse potential of each element was assessed. In this paper, the potential of the main elements of the system for reuse, which overall amounts to 98% by weight of materials used in the system, is described, together with the key barriers to material recovery of the dismantled elements.

This paper deals with experimental verification of semi-rigid timer connections using modern timber connectors Rothoblaas Alumidi. The experiment consists of the loading of timber bracket of structural wood. There are 4 alternatives of connection prepared. Each alternative has 4 specimens. So far, 4 specimens out of a total of 16 specimens have been verified. The paper describes the preparation of the experimental set-up, the loading procedure, the preliminary findings and the results of the performed experiments. These results are confronted with numerical calculations and assumptions of previous theoretical research. Experiment research continues with the testing of additional specimens.

The paper deals with the theoretical shape and stability analysis of a timber grid-shell structure. The peculiarity of the approach to the analysis of this type of construction is manifested in several parts of the design process due to the complicated shape of the roof plane. These specifics can be applied to the initial phase of creating the shape of the structure, which is directly related to the resulting static efficiency of the final design. Other important parts of the structural analysis that deviate from the standard-defined procedures are the determination of the design load by external climatic influences and the stability analysis with the need to apply a geometrically nonlinear calculation with the influence of initial imperfections.

Producers and suppliers of construction materials are dealing with rising prices of raw materials, semi-finished products and lots of different types of products. Insecurity of input raw material supplies for production is on the rise as well. This is due to the concurrence of many unfavourable circumstances.

Plastics are now being directed primarily to healthcare, mainly for the production of protective aids against virus transmission. A large amount of plastics is used for disposable food containers or packaging of goods, which is now more than ever ordered online. The outage of production capacity of global plastics producers in the USA has the biggest impact on plastics prices. Lack of plastics in the US influences significantly the quantity of plastics available on European markets. The subsequent withdrawal of plastics from China and Europe significantly contributes to logistics complications. Insufficient capacity of transport ships, aircraft and rail transport makes delivery times longer.

Reduction or termination of production of some smelters in Europe, rising emission allowance prices, tariff restrictions and a shortage of metals from Asia are contributing to raise metal prices. It is seen on the London Metal Exchange.

Although the long-term bark beetle calamity is not at its end yet, foresters have succeeded in stopping it in many places in the Czech Republic. Logging of bark beetle timber is decreasing and its price increases. The increase is caused not only by the decrease in logging, but also by export of this timber abroad, particularly to China, which is a phenomenon of the last two years.

Pandemic restrictions have impact on availability of workers for materials production, products logistics, sale and on-site assembly. There was a slowdown in construction output in spring and summer 2020. However, a recovery phase has been seen recently and demand for many materials exceeds supply.

This paper deals with the diagnostics of a timber load-bearing structure before planned renovation of covering structures. The roof and facade cladding can also change the load conditions, therefore, the inspection static design in this case is necessary. The planned object renovation is an opportunity for elaboration of diagnostic inspection of the supporting structure.

In simplified engineering calculations, the thermal-technical properties of wood are considered to be constant, but in real conditions they are moisture-dependent. This paper deals with the long-term measurement of absorbency at different initial and boundary conditions for the formulation of the coefficient of liquid water transport in wood for advanced computer modelling. A measurement procedure was designed to eliminate the effect of moisture transport in the measurement of water capillary uptake during partial immersion.

The present time in the Czech Republic brings a number of diagnostic problems and therefore the diagnostics is currently a widely used field for structural assessment. Otherwise, this is not the case with wooden structures. The paper presents groups of diagnostic methods used for diagnostics of wooden elements built into the structure, which are divided according to invasiveness (non-destructive, semi-destructive and destructive). For each group, the methods that are appropriate to the appropriate group and their brief description are named.

It was finished 18 390 houses in the Czech Republic. Houses are the most frequent finished type of buildings. The share of construction of brick houses is 83.1% and for wood-base houses its 14.9%. Database of 1520 bids for houses was completed and how what is typical Czech house. It is single floor brick house with sloped roof. The heating system is compiled by electric heater and radiators. Also house market analysis was made. 631 sold houses was examined in the period 2017-2020 in Brno-venkov district, Czech Republic. Only 1.3% wood-based houses was detected.

The paper is focused on the current issues of protection and strengthening of wooden structures. The wood used for them is a construction material whose mechanical properties are shaped by the nature and because it is also an organic material, it is subjected to various degradation processes. Types of wood protection includes all measures which would protect wood from influences of fungi, insect, weather (temperature, humidity, wind, fire etc.) and can be divided into chemical protection and radiation protection. Chemical protection can be further divided into protection against weather, biological pests and against fire. In our paper the solution of this weakness by photocatalytic materials (namely TiO₂) is presented. Those materials are efficient UV absorbers and they are able to destroy biological aggressors as well. Nowadays, there is not enough information about the interactions between wooden surface and non-photoactive or photoactive form of TiO₂. TiO₂ exists in many morphological forms. The planar particles were chosen for purpose of the experimental investigation. This material was applied on wooden surface for creating a transparent layer. The results are presented in the first part of the paper. If it is necessary to increase the load-bearing capacity of wooden elements, one of the possibilities is to strengthen them by applying a high-strength layer containing carbon fibers. The second part of the paper is devoted to this procedure with a detailed description of how to implement and design this reinforcement.

The paper is presenting problems that are to be solved within expert opinions focused on wooden houses which foundation is designed as a crawl space.

In modern building systems, sound insulation of walls is often made of multi-layer structures. This article deals with the acoustic operation of such structures and discusses the importance of proper implementation. It also warns against limited sound insulation at low frequencies, which is often not given enough attention. Software for calculating sound insulation - INSUL - was used to compare the acoustic behavior of structures and for simulations.

Contractors tend to ignore design solutions to reduce the cost of construction. Change of materials, absence of building elements, adjustment of layer composition, application of cheaper alternatives – these are common situations in construction practice. In certain cases, these modifications are without consequences, but in such a situation it is necessary, among other things, to take into account the laws of physics. This article deals with the case in which the structure was replaced – instead of the reinforced concrete ceiling slab, the contractor chose a wooden structure. Wood has significantly different properties than reinforced concrete, so it is necessary to take into account several aspects such as statis, thermo-technical properties and last but not least – with whitch this article deals with – moisture conditions in the structure. The relationship of wood and moisture is specific, the article assesses a specific case of such a structure, lists the possible consequences and finally suggests the most appropriate solution – adjusting the composition of this particular ceiling structure to meet the requirements.

Oak dowels find its use in carpentry joints, reconstructions of buildings and, also, dowel-joined CLT panels put together without adhesives. The article deals with influence of manufacturing techniques and shape of the cross-section on the bearing capacity of the dowels. Round shape (turning and perforation through steel hole) and hand hawing to the octagonal shape was tested. The results show negligible influence of manufacturing techniques on studied quantity.

The paper presents the results of experimental analysis and an analytical model describing the behavior of racking shear walls made of mechanically joined cross laminated timber. Tests of wall panels, tests for determination of stiffness of layers’ joints and material tests were carried out as part of experimental analysis. Outputs from the layer stiffness tests and material tests are used as input data for the analytical model. The analytical model is based on a component method that considers a wall panel as a system of interconnected elements. The action of the elements is described by springs with defined stiffness. The results of the experiments and the analytical procedure are then compared with each other.

The paper deals with the comparison of real energy consumption with values calculated in the Energy Performance Certificate (PENB) for two buildings: New low-energy family house and older apartment building. In both cases, these are wooden buildings. Subsequently, basic differences between the card and the reality in terms of energy consumption are defined in the form of house use coefficients.

Treatment of wood surfaces with various finish coating materials is recommended for long term protection of wood products exposed outdoor. Due to natural weathering, the colour and the surface roughness of uncoated wood is changed. However, in practice it can happen that wood in constructions has been weathered before to application of a finish. In this work, selected properties of sapwood and heartwood of pine (Pinus sylvestris, L.) surface such as surface roughness and adhesion of coating film were investigated on the surfaces of previous naturally weathered wood Two coating materials useable for wooden constructions in exterior conditions were used: dark brown polyurethane-based system and light brown oil-based surface treatment. The results of pull-off test for adhesion showed that the polyurethane coating film showed the weakest point in the pre-weathered layer of wood substrate and also at the wood/coating interface. The oil-based surface treatment had the weakest place inside the coating film or in the coating penetration layer in the wood substrate. Pre-weathering did not significantly affect the adhesion the coating film on wood. The result of the pull-off test for adhesion of both surface treatments was significantly greater on the heartwood surfaces than on the sapwood surfaces of the sound wood.

Survey of the real impact of historical and older constructions and constructions realized in the present period clearly shows that wood and wood-based materials are among efficient and still promising construction materials. The paper is compiled mainly on the basis of the knowledge gained during the verification of the properties of structures, in whose design and implementation the authors participated, and on the evaluation of the results of the survey of structures for the purpose of their remediation or reconstruction.

A wide range of requirements are laid out for stair construction, which are based on general construction requirements. These are mainly structural fire resistance, static resistance, mechanical resistance, appearance requirements and more. This article focuses on existing material and structural solutions for staircases used in modern wooden constructions and on the possibilities of using cement-fibre boards to build a staircase. The article summarizes the general advantages and disadvantages of this solution and represents the basic design solution.