Log Walls Research Articles

Fortified settlements of the XII–XIV centuries in the European Northeast. Pozheg hillfort (reconstruction experience)

The article presents a brief review of the results of studies of the fortification lines of the Pozheg hillfort – the only well-fortified settlement studied in the European Northeast (Komi Republic), which functioned during the XII–XIV centuries. This small hillfort (about 1550 m 2) was founded in the valley of the Vym River as an Old Rus outpost on the way to the Trans-Urals. It reached its greatest prosperity in the first half of the XIII century. The remains of buildings of three construction stages (XII, XIII and XIV centuries) have been studied by excavations at the site, the system of wood and earth fortifications (ditches, log walls, bulwarks) typical for small fortresses of medieval Russia has been discovered. An attempt is made to reconstruct the general appearance of the defensive structures of the Pozheg ancient settlement and a preliminary assessment of the main labor inputs in their construction is carried out. The types of fortress buildings are distinguished, the schemes of defensive lines, the size of the ancient settlement and their changes by stages of construction are considered.

НОВІ ВІДКРИТТЯ, ПРОБЛЕМИ ДОСЛІДЖЕННЯ ТА ЗБЕРЕЖЕННЯ ПІДЗЕМНОЇ СПАДЩИНИ ДАВНЬОГО ГАЛИЧА

The long history of changing ideas is considered and the hypothesis of the urban structure of ancient Halych of the 12th-13th centuries is demonstrated. according to archaeological sources. Based on the analysis of stratigraphic, planning and construction-technological features, the relative chronology of the appearance of the 16 studied relics of monumental architecture was established. The earliest monuments of the first half of the 12th century are examined in detail: an ensemble of palace buildings with a post construction of log walls, the use of a plinth and a tin roof on Kryloska Hill, a complex of churches on Tsarynka, the Church of the Savior on Karpytsia Hill, as well as other objects, on which recent discoveries have been made. The appearance of early sacred objects outside the city is explained by the gradual Christianization of the population of Halych. Analysis of the construction periodization of the Dormition Cathedral in the middle of the 12th century. allows you to review its graphic reconstructions until now and raise the question of developing a new hypothesis of the three-dimensional appearance of the building during the first construction period, from which the recently found detail of a large alabaster ornamentally decorated capital with traces of false gilding comes from. The results of architectural and archaeological soundings at the outer contours of the foundations of the Panteleimon Church confirmed the presence of regular external protrusions of the foundations, which calibrates the construction of the object together with the early paleographic dates of the early 90s of the 12th century. Part makes it possible to argue the use of a measuring foot of 30 cm. Attention is drawn to the problems of preserving a number of known architectural and archaeological objects and the search for unknown monuments by non-invasive research methods.

Buildings made of massive timber logs with a derogation from the application of technical conditions for traditional masonry technologies

Timber log walls are a unique form of construction - erected from solid material, they are both a building structure and a thermal barrier. Walls of wooden logs have numerous advantages, especially favourable physical and mechanical properties, including insulation and thermal capacity. The technical conditions, which are the Polish interpretation of the Nearly Zero Energy Building (nZEB) building, which a newly designed building must meet, must meet 2 conditions simultaneously: the value of the EP index, which determines the annual calculated demand for non-renewable primary energy for heating, ventilation, cooling and preparation of domestic hot water for the entire building, and adequate thermal insulation of the external walls. Calculating the thermal insulation of a wood partition, relying only on thermal conductivity coefficients without considering other properties of the material, does not reflect the true insulating properties of wood. The lack of research on the insulating properties of wood, and thus the lack of national technical and installation requirements for log houses seriously limits the development of this type of construction and forces to undertake reliable research and development work in this area. The proposed introduction in this type of building of the methodology of the so-called Integrated Energy Design (IED) allows to carry out multi-criteria analysis of design variants at the stage of the virtual model in the BIM standard, in terms of the final energy efficiency of the building. Conducting various types of variant analyses and simulations allows to achieve optimal energy efficiency and to verify and correct the adopted solutions. The high energy efficiency of the building demonstrated by such simulations can be the basis for a deviation from the current regulations, which will allow the implementation of newly designed buildings in massive log technology, without the need for additional thermal insulation. As a result, it will be possible to preserve the unique architectural expression of buildings erected with this technology, with visible massive timber logs both on the exterior facades and on the interior.

Risk factors for moisture damage presence and severity in Finnish homes

Moisture-damaged buildings are a prominent issue in Finland, but with limited information on damage prevalence, degree of severity and risk factors. This paper analyses 14,996 Finnish detached and semidetached houses that have undergone a standardised moisture assessment of interior spaces and at-risk structures inside the building envelope. Confirmed damage (a binary indicator of damage presence) and a damage index (an ordinal indicator of severity) were calculated for each home and their association with different building and area characteristics estimated. Frequently damaged structures include pre-1950s log walls, walls contacting soil, wooden ground floors and false plinths. Around 15% of surveyed houses had risk structure damage, 19% had at least one confirmed damage anywhere in the house and 49% had either confirmed, likely or possible damage. The greatest risk factor for confirmed damage was house age (odds ratio = 1.48 (95% confidence interval (CI) = 1.45–1.51) for each decade since construction), with nearly half of all houses built pre-1939 damaged. Other risk factors explained a third of the effect of building age, and included log external walls, fibreboard roofs, absence of mechanical ventilation, detached properties and wind-driven rain precipitation. Results can support targeted remediation efforts, protect health and estimate exposure–response relationships for moisture damage. Practice relevance Moisture damage in homes causes various health concerns for occupants, and in colder climates such as Finland such damage often occurs within the building structure. This study finds confirmed moisture damage in 19% of surveyed Finnish homes. Most damage was within the building structure, supporting the need for surveys investigating inside known-risk structures. Older homes had much higher damage risk, reflecting different construction methods and ageing, but also suggesting modern building standards are helping to reduce damage. Increased risk in higher wind-driven precipitation regions indicates a need for regulations and research that improve the resilience of all housing to the projected increases in driving rain from climate change. Understanding the building characteristics and structures that increase moisture risk can support targeted remediation and maintenance in vulnerable buildings, conserve older buildings and avoid demolition, and help protect occupant health.

Numerical Modeling and Parametric Assessment of Log Shear Walls with Bonded Corners

ABSTRACT The paper investigates the stiffness and strength of log walls with standard and dovetail bonded corners under lateral loads. The finite element model is developed and validated with experimental work at small-scale and wall-scale levels. The validated wall-scale model was modified by conducting a detailed investigation on assessing the wall behaviour with varying crucial parameters, including coefficient of friction, vertical load, geometric irregularities, and the wall’s aspect ratio. The study suggested various techniques for improving the wall’s lateral load resistance capacities and initial stiffness, employing steel and wood pins.

In-Plane Investigation of Log Walls with Various Orthogonal Joineries Employing Finite Element Modeling

ABSTRACT Log house construction is a well established style of home building across many centuries. Orthogonal joineries classically guarantee structural strength in log house construction. The paper investigates the structural response of log walls with orthogonal, standard, and Butt-and-Pass joineries under lateral loads. Finite element models are developed and validated through comparisons with available experimental results. Various parametric studies are presented assessing the effect of the penetration length, openings, reinforcement methods, log profiles, and log wall orthogonal joineries on the lateral strength and stiffness of the wall systems. The study indicates a significant impact of these parameters on the log wall lateral load-resisting behaviour. Finite element models show that the log walls with the TR system (three bottom and three top logs were tied with the rods) demonstrated the greatest maximum lateral resistance, followed by the Tie-down system. Generally, a greater initial stiffness was indicated in the log walls with the Tie-down system, followed by the TR system.

Investigating the structural response of log walls to lateral loading: A parametric study of geometric and material parameters

This paper investigates the structural response of log walls commonly employed in log construction. Finite element models are validated with experimental work for predicting the lateral performance of log walls. Parametric studies are carried out assessing the effect of friction coefficient, opening ratio, and reinforcement methods, on the initial lateral stiffness and the lateral resistance of the log wall. The study also examines the response of reinforced log walls with window and door openings and indicates that including such openings in the wall reduces initial in-plane stiffness by 8% to 18%.

Albazin: Russian outpost on the Amur

The article examines the architecture of the first wooden fortress in the Amur region, which became a kind of outpost on the border with Manchuria. The author analyzes the planning structure of the fortress and its design features associated with the change of the first fort with palisades to a fortress with log walls, and then a timber-earth fortress surrounded by an earthen rampart. The article was written on the basis of a study of literature, archival materials and a field study conducted by the author at the site of the Albazin fort in 2009.

The History, Localization and Architecture of the Urtamsky Ostrog

Purpose. An important direction in the historical and archaeological research of the Siberian ostrogs at this stage is the solution of specific problems associated with the main events of their history. This study is devoted to solving a set of problems related to the history and archaeology of the Urtamsky ostrog in Kozhevnikovsky District of the Tomsk Region: it’s localization, the determination of the foundation date and reconstruction of its architectural appearance, taking into account its transformation over time. Results. Based on the analysis of the written sources, it is proved that the ostrog was founded in 1685, contrary to the point of view in the historiography that the ostrog was established in 1684. Based on the analysis of the written sources, cartographic material and archaeological survey data, a reasoned hypothesis is made about the location of the Urtamsky ostrog on the north-eastern outskirts of the modern village Urtam. Here, material was gathered and artifacts from plundering excavations were collected, indicating the long-term presence of the Russian population in this area. In the course of analyzing the complex of written sources, it was established that the ostrog from the moment of its foundation until the mid-1730s at least once was substantially rebuilt, which resulted in the construction of a new log wall and the replacement of the two corner barn towers with the two gate towers. An analysis of the architectural parameters of the first Urtamsky ostrog showed that the log walls were equal in height to the height of the tower log cabins (about 4 m). Only the roofs of the towers towered above the log wall. At the same time, the towers themselves had a squat appearance and served as barns. Probably, it was this circumstance that prompted S. U. Remezov to depict the Urtamsky ostrog as having no towers, since the towers, neither architecturally nor functionally, did not fully correspond to their classical appearance and purpose. It is possible that the other ostrogs, depicted by S. U. Remezov with no towers, had towers similar to those of the Urtamsky ostrog. Conclusion. The study made it possible to significantly clarify the history of the origin and the reconstruction of the Urtamsky ostrog. The prospects for further research of this object are associated with the archaeological excavations.

Impact of Vapor Barrier on Moisture Content of Fiberboard Insulation in Log Structure.

The paper is focused on a verification of the moisture content of fiberboard insulations in the multilayer loadbearing log wall designed with and without the vapor barrier. Experimental verification was done using a sample of the multilayer loadbearing log wall built in a research timber structure building under in-situ conditions. Indoor properties of the building met conditions for human occupancy. The experiment was performed for 2 years and 3 months. Aims of the fiberboard insulations moisture content verification in the walls were to verify the effect of vapor barrier in various periods of the year and verify excessive moisture in the fiberboard insulations, which is undesirable in terms of biodegradation. The results of measuring the moisture content showed that after a certain period, the difference of insulation moisture content in the wall including and excluding vapor barrier is negligible, as well as other results and conclusions for designing the composition of multilayer loadbearing log walls.

THE UPPER PART OF THE PTICH RIVER IN THE 10th—11th CENTURIES. (BASED ON RESEARCH MATERIALS OF BURIAL MOUNDS)

The Ptich river, a left tributary of the Pripyat, flows through the southern part of Central Belarus. Its banks are mostly swampy. The most suitable land for farming is located in the upper parts of the river, on the territory of Minsk district. The location of 60 burial mounds specifically connected with this region (fig. 1), but unfortunately most of them had not been preserved. Only five sites were investigated by archaeological excavations. Six burial mounds with cremation were explored in the burial ground of Ozerzo which dated back to the the second half of the 10th century (fig. 2—5). Wooden constructions of log walls and boxes were fixed in some mounds, which might be compared with the traditions of the Slavs of the Raikovetskaya and Romny-Borshevo Cultures. The grave goods are presented by artefacts connected with subculture of armed force centers and prestigious women’s jewelry (fig. 6—8). The burial ground of Ozertso could be the part of a large one and now this necropolis was completely destroyed. It can only be assumed that the site was an integral part of the settlement on the Menka river, which was the original location of Minsk. Some prestigious women’s jewelry made of silver was also found in the plowed area nearby (fig. 9). Such places as Gorodishche, Dudovka, Priluki related to the burial grounds of the nearest district of the settlement on the Menka river present cremations of the late 10th century and inhumations of the 11th century (fig. 13, 14). Axes were found in men’s burials, and ornaments typical of the Dregovichy were discovered in women’s ones, pottery was found both ways (fig. 10, 11, 15—18). The studied burial ground of Dovborovo up the Ptich river provides cremations and inhumations and grave goods which dated back to the late 10th — the first half of the 11th century and display typical rural items (fig. 12).
 Thus, by the late 10th century, the entire territory of the upper reaches of the Ptitch river was inhabited. The trade and craft settlement was founded on the banks of the Menka river, the right tributary of the Ptitch, which in the early 11th century turned into a well-fortified pre-urban place. Burials in the necropolis of this settlement are distinguished by a variety of ritual elements and prestigious grave goods. A new fortified place of Minsk was built on the Svisloch river in the second half of the 11th century, which later became the center of the Principality. The intensity of life in the region of the upper Ptitch river was gradually decreasing by the 12th century, and numerous rural settlements were connected to the new center.

Hygrothermal performance of an old building with log walls from the region of Vestfold in Norway

Hygrothermal performance of an old building with log walls from the region of Vestfold in Norway

Experimental Measurements of Wooden Solid Log Wall

The contribution brings findings accrued from alternative design of log-wall’s lateral joint. The lateral joints present without question a thermal bridge highly repeating in the construction of external log wall. Field of the research was a theoretical design of wall models, simulation in software ANSYS and comparison theoretical results with results gained from the laboratory measurements of wall samples. Bed joints of wooden solid log walls are still a problematic detail in terms of thermal technology. By reason of weakening in the place of lateral joint and the value of coefficient of thermal conductivity, the solid wooden log wall does not meet requirements of Czech Standards ČSN 73 0540-2 posed to the value of wall’s thermal resistance. That is why we have focused on measurement of surface temperature, which is also one of the classified factors in term of construction quality. The project particularly focused on monitoring of surface temperatures in the areas of critical details – bed joints.

Hygrothermal performance of log walls in a building of 18th century and prediction of climate change impact on biological deterioration

Several studies underline the dramatic changes that are expected to take place in nature and environment due to climate change. The latter is also expected to affect the built environment. Particular emphasis is currently given to the impact of climate change on historical structures. Within this context, it is important to use simple methods and novel tools in order to investigate specific case studies. In this study, the climate change impact on the hygrothermal performance of the log walls in a historic timber building is presented. The building under investigation is the Fadum storehouse, also known as ‘the coated house’, located in Tønsberg, Norway. The storehouse dates to the late 18thcentury. It has a particular design with the main features of stumps or piles up to which it stands and the ‘coating’ that covers its outer walls. The main damage of the construction is related to the biological degradation of the wood. The hygrothermal performance of the log walls, as well as the exterior and interior climate, have been monitored and the results have been used to validate a Heat, Air and Moisture transport (HAM) model. The validated HAM model is then used to examine the performance of the log walls for both current and potential future climate conditions. The transient hygrothermal boundary conditions serve as the input parameters to a biohygrothermal model that is used to investigate the biological deterioration of the building components. The findings reveal that currently there is no mould risk for the main body of the construction, which is in accordance with the visual inspection. The passive systems of the building are highly conducive to these results, since they protect it from driving rain and other sources of moisture and eliminate the potential impact of future climate change risk scenarios.

Analysis of acoustic insulation in traditional wooden architecture hotel building

This paper presents evaluation of vibroacoustical requirements in the context of impact and airborne sound insulation in hotel building. This building represents traditional wooden architecture present in southern Poland. Similar structures can be found all around Europe in mountainous areas. Due to fact that there are little information about acoustic conditions of such buildings, this paper gives measured values of sound insulation of typical solutions used in this architecture. In order to define if requirements of current polish standard PN-B-02151-03:2015 for hotel buildings are met, impact sound level and airborne sound insulation of representative partitions were measured. Measurement conducted in presented building shows issues connected with non-sufficient airborne sound insulation of internal partitions – timber log walls. Due to its low mass and, in simplification, homogenous structure, its sound insulation is far from meeting requirements. Considering timber structural ceiling and reinforced concrete floor present in hotel building requirements of impact sound level and airborne sound insulation are met. The solution of weak acoustic conditions of walls is proposed as plasterboard pre-wall with mineral wool inside.

The Structural Design of Wooden Solid Log Wall

Alternative solutions to joints of outer wooden solid log walls are based on the current situation on the construction market, which reflects general change in attitude towards the environment. Apart from the evaluation of materials and products in accordance with technological and economic aspects, attention is paid to the effect of individual elements on the environment. This trend is reflected in construction practice by a comeback to original materials and expanding designs of residential buildings on the basis of easily renewable material resources, e.g. wood, which is relatively easily available and renewable construction material. When designing and constructing wooden buildings, it is necessary to take into account specific properties of wood (particularly volume changes), which need to be considered for solutions of individual details. Bed joints of wooden solid log walls are still a problematic detail in terms of thermal technology. It is a contact of two horizontal construction elements – beams, where maximum weakening of the wall thickness occurs. This spot is a relatively frequent place of a recurring thermal bridge during the wall construction. Analysis and improvement of this critical place of wooden houses, which has been more and more frequently built in the Czech Republic, would lead to their better evaluation in terms of heat-technical properties. The aim of the project was to design and examine adjusted variants of shape solutions of joints in between individual solid wooden elements. The project particularly focused on monitoring of surface temperatures in the areas of critical details – bed joints.

Documenting Heritage at Risk: Vernacular Farm Houses in the Eastern Tibetan Cultural Region

Tibetan architecture is largely associated with the impressive monastic buildings scattered over the Tibetan Plateau and the adjoining mountain ranges. While these buildings have long attracted the interest from travellers and researches, the rural vernacular architecture has been grossly neglected. Accounting for more than 90 percent of the cultural heritage vernacular farmhouses incorporate an immeasurable wealth of traditional knowledge and local craftsmanship that is increasingly threatened by the impacts of modernisation. The article draws on a research project on vernacular architecture in the Tibetan cultural region and presents four examples of rural houses in former Kham, that is nowadays spread across Sichuan, Qinghai, Yunnan provinces and the Xizang (Tibet) Autonomous Region. The examples show a surprising diversity in terms of style, size, layout, building materials and structural systems that are perfectly adapted to local climatic and topographic conditions as well as the resources available in a particular environment. As examples for this diversity the article presents a rammed earth building in Chatreng, a house in stone masonry from Dabpa, a house in Pome built with timber log walls, and a house from Gyalrong with a mixed stone/timber construction. The richness of vernacular farmhouse architecture in Kham deserves special recognition and support on various levels.

Log House – A Blueprint for Future Energy Efficient Buildings?

Log houses are the oldest way to build homes in Northern Europe. Still today, almost all the buildings in many rural villages in Finland, Estonia and other countries are log houses. They are a very important part of identity in the built environment. In today's building industry, however, log houses stand mainly for the vacation homes, for the nostalgia in us. In the discussion on energy efficient buildings, however, the log house hardly plays any role at all. But there is no reason why log houses wouldn’t work as sustainable buildings. Wood is an ideal material for energy efficiency, has a negative carbon footprint and is widely available as local material. Therefore, this log house project in a village near Tampere was designed to study the potential of the log house in both modern, sustainable architecture and energy efficiency. The log house is built with a double log wall. This way, it is possible to reach passive house level insulation with massive wood walls because the double log wall eliminates the usual thermal bridges in a wood construction as both walls are load bearing. The biggest challenge is bringing the natural properties of a log house – the settling of the wood and lacking air tightness in the joints when the wood dries out – together with the air tightness as the key element for energy efficiency and building physics. To reach a reliably airtight envelope, a new method was engineered for building the log walls: The inner wall was built first. After that, a vapour barrier was wrapped around it, and only then the outer wall was raised. This way, bringing the vapour barrier to its place was not only easy, but also very accurate and safe – the only seam in the vapour barrier was bringing together the start and end point. Another challenge is the building physics as the façade can’t be ventilated. The insulation lies directly behind the outer wall. WUFI-analysis shows, however, that the wall construction is still on the safe side with the moisture. The airtight envelope is an important factor, as is the adaptive vapour barrier that is very tight at low relative air humidity and up to 100 times more open at a higher air humidity. The project shows that a log house is a truly sustainable building with a low carbon footprint, airtight building envelope and a safe building physics. Together with the long tradition in Northern Europe they are worth a deeper view in the field of sustainable building.

Heat Thermal Transmittance of Log Wall

This paper deals with the problem of heat thermal transmittance of log walls. Log and cabin are now very popular among investors, so this paper deals precisely with this issue. This paper deals precisely with this issue use physical quantities according EN ISO 7345, which are decisive parameters for this type of wall. It is detailed decribed test log walls, including all specifics for this wall.

Determination of stress-strain state of the wooden church log walls with software package

The restoration of architectural monuments is going on all over the world today. The main aim of restoration is the renewal of stable functioning of building constructions in normal state. In this article, we have tried to figure out with special software the bearing capacity of log cabins of the Church of Transfiguration on Kizhi island. As shown in research results, determination of stress-strain stage with software package is necessary for the bearing capacity computation as well as field tests.