Log Wall Research Articles

Hygrothermal performance of hybrid multi-storey buildings under future climate scenarios

Climate change, energy efficiency, and carbon footprint objectives pose significant challenges to the hygrothermal performance of building structures in climates with extreme temperature variations. To meet long term sustainability targets, buildings designed for a lifespan of up to 100 years must exhibit resilience not only to current climate conditions but also to projected future scenarios. This study evaluated the hygrothermal performance of a hybrid log-concrete multi-storey building, combining the structural strength of concrete with the sustainable, moisture-regulating properties of wood, to address energy efficiency and moisture control challenges in subarctic climates. Onsite measurements were validated using numerical simulations to assess hygrothermal performance of log wall structure under climate change scenarios. Results showed minimal mould growth risk under present conditions, while future climate projections (RCP8.5 for 2080) indicated a maximum mould index of 1.32 near the exterior log surface. These findings highlight the resilience of log-based structures in cold climates and underscore the need for proactive moisture management under warmer, more humid future scenarios. Stable ideal indoor temperatures (averaging 21.56 °C to 22.09 °C) and effective moisture control (with a maximum average moisture excess of 0.89 g/m3) over the measurement period further demonstrate the suitability of hybrid log-concrete buildings for energy-efficient, moisture-regulating construction in cold climates. The study recommends surface treatments that allow vapour diffusion while preserving wood’s hygroscopic qualities to enhance durability in changing climates.

Методологический анализ практики фрагментарной регенерации исторической среды на примере стены Угличского кремля

The paper considers the designing process of historical environment regeneration from a methodological point of view. The authors present a systematisation of the main principles and methods of the contextual approach to the design of historical environment reconstruction and regeneration. The authors also give recommendations for optimising the design solutions of the regeneration objects in the historical environment. The project of fragmentary reconstruction – regeneration of the Uglich Kremlin log wall is considered as an example of methodological analysis.

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%.

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.

Nature-Based Coastal Protection by Large Woody Debris as Compared to Seawalls: A Physical Model Study of Beach Morphology and Wave Reflection

Anchored Large Woody Debris (LWD) is increasingly being used as one of several nature-based coastal protection strategies along the north-western coasts of Canada and the US. As an alternative to conventional hard armoring (e.g., seawalls), its usage is widely considered to be less harmful to the coastal ecosystem while maintaining the ability to protect the beaches against wave attack and erosion. The effects of seawalls on beaches have been extensively studied; however, the performance and efficacy of LWD and its potential as a suitable alternative to seawalls (and other shoreline protection structures) are still understudied in current research. This paper presents and compares the effects of a conventional vertical seawall with two different LWD structures on beach morphology and wave reflection through large-scale physical modeling in a wave flume at a 1:5 scale. An assessment of techniques used to measure beach morphology and an assessment of model effects were included in the study. It was found that the wave reflection could be reduced by using a single log instead of a wall structure, while changes in the beach morphology response largely depended on the type of the LWD structure. A stacked log wall showed near-identical behavior as a conventional seawall. Visible model effects from the experiments, including the effect of the flume sidewalls on the beach morphology, were quantified and analyzed to inform future research.

АРХЕОЛОГИЧЕСКОЕ ОБСЛЕДОВАНИЕ ЛЕВОБЕРЕЖЬЯ УСТЬЯ Р. УРТАМКА (КОЖЕВНИКОВСКИЙ РАЙОН ТОМСКОЙ ОБЛАСТИ)

The article is devoted to a review of the archaeological survey results of the left bank of the Urtamka River mouth (the Kozhevnikovsky District of the Tomsk Oblast). The purpose of the research was to localize the station of the Urtam ostrog, marked on the map of 1701 by S.U. Remezov, located on the left bank of the Urtamka River. The survey of this territory made it possible to detect an elevated area (Urtamskoe-II), fenced on three sides by a sub-square ditch 2 m wide and 0.4 m deep. The total dimension of the fence was 200 m, which formally correlates with the perimeter of the Urtam ostrog, indicated in a written source of the late 17th century (1687). However, the archaeological study of the ditch section and the inner fenced area of the newly identified fortified settlement Urtamskoe-II did not reveal the cross-section of the ditch and the foundations of the log wall that are characteristic for the Early New Time. Such results complicate their connection with the Urtam ostrog. In addition, the osteological materials and fragments of the rims of ceramic vessels from the Irmen culture (Late Bronze Age) were found in the cultural layer of the discovered settlement. It should be noted that for the territories occupied by several archaeologically investigated ostrogs (Tomsky, Umrevinsky, Sayansky, etc.), the facts of the discovery of the earlier archaeological materials are quite typical. However, the ditch fence of the sub-square outlines of the residential area of the fortified settlement Urtamskoe-II significantly distinguishes it from the nearest Irmen settlement of the Baturino-1. Fencing with a “П” shaped moat are more typical for the settlements of the late Middle Ages on the territory of neighboring Baraba (Tyumenka, Chinyaikha). In general, the archaeological research carried out reflected the general tendency which is the complexity of localizing the ostrog as an archaeological site. Keywords: archaeological exploration, Upper Ob Region, ancient settlements, settlements, ostrog

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.

EXCAVATION SITE IN OKTYABRSKAYA STREET (TOBOLSK)

The article gives a historical interpretation of a stakewall with an underground passageway found in the cen-tral part of the upper posad drawing on the materials from the excavation site in Oktyabrskaya Street (204 m2). The thick log wall consisted of vertical posts erected at the bottom of a specially dug ditch. The underground pas-sageway constituted a manway, starting on one side of the stakewall and ending on the other. Its ceiling and walls were covered with planks supported by low half-logs, thick planks and small logs. The plank ceiling of the under-ground tunnel was just below the base of the log wall, with the horizontal adit being so small that one could only crawl through it. In order to determine the absolute age of the stakewall, we carried out the dendrochronological and radiocarbon studies of its logs. For the purpose of identifying this object with one of those mentioned in writ-ten sources, we reconstructed the history of fortification construction and localisation by performing a detailed analysis of historical data and all known plans of the city. As a result, it was established that the wall found during the excavation in terms of its location and orientation better correlates with the building shown on S.U. Remezov’s plans, which was located in the central part of Trinity Cape and surrounded by a rectangular stakewall, rather than with the posad fortifications. On the plans of 1687 and 1688 from the Chorographic Drawing Book, the object in question was captioned as ‘prison’ and ‘prison yard’. This assumption allows us to date the log wall discovered in Oktyabrskaya Street at 1687, or, quite possibly, at an earlier time. This prison yard fence could be used after 1714 and, judging by the stratigraphic and planigraphic observations made at the excavation site in Oktyabrskaya Street, until the period of stone construction in the upper posad.

Energy performance of five different building envelope structures using a modified Guarded Hot Box apparatus—Comparative analysis

The most of thermal characteristics of buildings are currently calculated by simplified mathematical models of building envelope behaviour. The main parameter needed for these calculations is the thermal transmittance. The aim of this study is to evaluate thermal performance of several building envelopes suitable for thermal insulating purposes and to compare parameters of thermal performance given by national standards or the thermal performance declared by producers. The experimental measurements were conducted with dynamic conditions in the cold chamber of the Hot Box. Dynamic testing was running under weekly temperature cycle using programmable temperature controller in the cold chamber. Hot site temperature was kept steady according to controlled ambient temperature. Behaviour of each system was investigated under similar conditions with room temperature 22–23 °C in the hot chamber and with temperature fluctuation between +6 °C and −13 °C in the cold chamber. This study provides interesting results. Especially heat flow in case of laminated log wall (massive wood) of thickness 200 mm was measured as significantly lower than it would be calculated by currently known thermal conductivity of soft wood. The presented method of thermal transmittance measurements in dynamic conditions might bring increasing accuracy for building envelope energy loss calculations. The difference between result from one-week long test compared with 20 days long test of the same sample was found as 2,3%. Correlation coefficient between experimental values and calculated total energy loss in time was always found higher than 0,997 and accuracy seems to be increasing with length of the measurement.

Kinematics and electromyographic activity of horse riders during various cross-country jumps in equestrian

ABSTRACT The objective of this study was to identify the key biomechanical patterns (functional muscles and kinematics) of amateur horse riders during various cross-country jumps in equestrian. Eleven riders first performed a control condition that corresponded to jumps over three different obstacles (log wall, brush and tree trunk) before jumping over the same three obstacles in a cross-country course. 3D Kinematics and electromyographic (EMG) activity was synchronously collected which included seven muscles of the riders back, lower and upper limbs. Maximum voluntary isometric strength of knee extensors was also measured before and immediately after the race to investigate potential fatigue. Our results showed similar EMG activity for the different obstacles. Whereas some kinematics alterations were observed between obstacles. Moreover, back movements alterations were recorded between the jumps of the cross-country as compared to the control condition. Finally, muscle strength was not altered after the race. In conclusion, our study indicates that upper and lower body muscles contributed to the realisation of various jumps during a cross-country and that the different configurations of the obstacles did not induced specific muscular and kinematic responses.

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.

Airtightness improvement solutions for log wall joints

The air leakage rate of handcrafted log wall and window joint and handcrafted log wall corners using Scandinavian saddle notch or dovetail notch were measured in the laboratory in an airtight measuring chamber. In the first test setup, the joint between the log wall and a window frame was sealed using various commonly practiced methods. Commonly used sealing methods were applied on both corner notches and the joint between logs to evaluate the effectiveness of these sealing methods.The best natural sealing material was peat moss that reduced air leakage of Scandinavian saddle notch by 77% and that of the dovetail notch by 84%. The best modern sealing material was special joint sealant that reduced air leakage of Scandinavian saddle notch by 87% and that of the dovetail notch by 70%. After improving the dovetail notch with PU foam, the air leakage reduced to 94% compared to the original unsealed version.

Evaluation of a technical survey and the renovation needs of old rural wooden houses in Estonia

Wooden detached houses represent the majority of buildings in rural areas in Estonia. The design service life of these rural wooden building is nearing its end. Before starting major renovation of these houses, a comprehensive survey of the buildings is required in order to determine all the visible and hidden damage of constructions. A renovation plan may be composed after the houses’ technical condition has been examined completely. This paper provides a description of the issues that need to be reported in a technical survey of an old log house. The relevant survey method was tested on 50 houses in Estonia. Besides describing survey components and methods, detailed information is given about building envelope elements and possible variations. All detected damage is described and illustrated with drawings and photographs. Every envelope component of a house should be checked for possible damage during an inspection. There are hidden components, especially below the floor where opening the construction or using a flexible camera is needed for an inspection. Most often, rot damage was found in foundation wall and log wall joints, the main reasons for it being broken or missing rain protection or waterproofing for the edge of the foundation. Often damage was identified in crawl spaces (floor beams) and near water leaks in the roof.

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.

Avoiding mould growth in an interiorly insulated log wall

Interior thermal insulation in a cold climate is risky from a hygrothermal point of view. Designers and customers are looking for solutions that provide a moisture-safe design. Avoiding mould growth in wall structures is the primary design criterion when planning to add interior insulation to a log wall. In this study indoor humidity load, average indoor temperature, the thickness of a log wall and additional insulation layer, the initial moisture content of logs and the vapour diffusion thickness of a vapour barrier were varied and mould growth risk was identified. In general, our results showed that a water vapour barrier with an equivalent vapour diffusion thickness of 2 m or more is acceptable when indoor moisture excess is up to 5 g/m3 during winter. In these conditions, the maximum measured moisture content of logs before insulation should be below 12% and the thickness of interior insulation of mineral wool can be up to 50 mm. The water vapour resistance of a vapour barrier depends on the use of the house (for general living or as a summer cottage) and indoor humidity load. It is necessary to install a vapour barrier covering interior insulation carefully to avoid air leakages through it. If an improved vapour barrier and decreased indoor moisture excess are used, then the thermal resistance of an additional internal insulation layer can be more than double of the thermal resistance of the log wall before adding the insulation, otherwise both thermal resistances should be equal.

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.

Light Weight Earth Material and its Application in the Alteration of Log Dwellings

In the construction of log building, the building's insulation effect is mainly achieved by the timber tightly connected, which usually requires a large flat timber that lead to the consumption of high-quality wood.In recent years, by the decline in quality of forest resources, existing log buildings are constructed with fast-growing wood which small diameter, and larger curvature. Compared with the traditional log building, the log wall constructed with fast-growing wood has wider gap, poor insulation and poor pest control.So it greatly increased consumption of firewood for heating.To compensate for this defect, this paper make a study of log building constructions wall structured with light weight earth material. Mixture of plant fibre and cement, is used as main reinforce component, together with raw soil to enhance the ability of anti-cracking and heat preservation, fixing the mixture of ligth clay on inner side of the construcion's wall to enhance the ability of heat preservation and getting smooth wall surface by fill the gap in the wall, and easy for decorating interior wall.

ACOUSTIC INVESTIGATIONS OF THE EXTERIOR AND INTERIOR WALL OF A LOG HOUSE / RĄSTINIO NAMO IŠORINĖS IR VIDINĖS SIENOS AKUSTINIAI TYRIMAI / АКУСТИЧЕСКИЕ ИССЛЕДОВАНИЯ НАРУЖНОЙ И ВНУТРЕННЕЙ СТЕНЫ БРЕВЕНЧАТОГО ДОМА

With the rapidly changing environment and growing cities and increasing traffic flows the problem of noise pollution is becoming more and more relevant. As street networks continue developing and land prices are rising, houses are more and more often built close to especially noisy suburban streets. Traffic-generated noise accounts for up to 80% of the prevailing noise level. Many people build private houses from eco-friendly building materials, such as wood. The construction volumes of log houses, roadhouses and guest houses have increased. This article presents acoustic investigations of a log house's D nT,w measured under natural conditions in the natural environment – a constructed log house – and in a noise suppression chamber, analysing an element of the log wall. The log wall concerned was covered with log house heat-insulation materials and the obtained D nT,w results reached up to 58 dB. Santrauka Aplinkai kintant, didėjant miestams ir plečiantis transporto srautams, vis aktualesnė tampa triukšmo namuose problema. Plečiantis gatvių tinklams, brangstant žemei, vis dažniau namai statomi netoli užmiesčio gatvių, kuriose aukštas triukšmo lygis. Iki 80% vyraujančio triukšmo lygio – tai transporto keliamas triukšmas. Daugelis gyventojų statosi individualius namus, o jiems statyti renkasi ekologiškas medžiagas, pavyzdžiui, medieną. Vis daugiau statoma rąstinių namų, pakelės užeigų ar svečių namų. Aprašomi akustiniai rąstinio namo sienos tyrimai, atliki natūroje ir triukšmo slopinimo kameroje. Rąstinė siena dengiama populiariomis rąstinių namų šiltinimo medžiagomis. Tiriamas vidinės sienos triukšmo izoliavimo koeficientas. Резюме В связи с изменением окружающей среды, ростом городов и увеличением транспортных потоков возрастает актуальность проблемы бытового шума. По мере развития уличной сети, роста стоимости земли строительство домов все чаще ведется на загородных улицах, отличающихся высоким уровнем шума. Шум, вызываемый транспортом, составляет до 80 % преобладающего шума. Многие жители строят индивидуальные дома и выбирают для их строительства экологичные материалы, такие, как древесина. Увеличивается строительство бревенчатых домов, придорожных кафе или гостевых домов. В статье описываются акустические исследования стены бревенчатого дома. Исследования проведены в естественных условиях и в шумоподавляющей камере. Бревенчатая стена покрывается популярными материалами, используемыми для утепления бревенчатых домов. Исследуется условный фасад дома и коэффициент шумовой изоляции внутренней стены.