Search

You Buildings designed for coming decades are more susceptible to global warming, rising average temperatures, and heat waves, which are of a greater risk than in the 1990s. Simulation-based design decisions may be inaccurate if just historical data is used to generate climate files. The building's energy performance, cooling and heating system’s design, and room unit sizing require reliable weather data. So far mainly historic meteorological data has been used for simulations. Annual simulations and cooling/heating system design often use a typical meteorological year (TMY) based on historical data using ISO 15927-4 and ISO 15927-2 thorough instructions for TMY for annual simulations and design day data. The above climate models lack the data needed to construct TMYs for building performance simulation (BPS) tools. Climate model forecast accuracy must also be examined from the BPS perspective. This work aims to illustrate and test methods for producing TMYs using three climate models with different resolution and modality in Tartu, Estonia, from 1985 to 2015. The ISO 15927-4 approach selected months from historical meteorological data appropriate for each climate model. Three BPS TMYs were created, and a reference building's energy needs simulated. Long-term historical data was used to simulate the reference building's energy requirement and develop TMYs. The results showed that all the TMYs developed based on NorESM, MPIESM and ECEarth climate models can represent well the energy needs obtained with the TMY based on historical weather data depending on the TMY generation method while MPIESM shows deficiency in cooling season. TMY based on NorESM have the most consistent energy need simulation results while TMY based on ECEarth also performs well both for predicting cooling and heating needs. The future work includes finding other suitable methods for TMY generation that results in even less errors for all models and further validation with other reference buildings for final climate model selection to develop future climate scenarios.

Fiber-reinforced plywood is a composite material that combines the natural strength and rigidity of plywood with the added durability and resilience provided by reinforcing fibers. This type of plywood is designed to offer improved characteristics over standard plywood, including enhanced strength, stiffness, resistance to impact and moisture, and environmental degradation. By integrating reinforcing fibers, such as glass, carbon, or natural fibers (like flax, bamboo, or hemp) into or onto plywood, manufacturers can create a material that is better suited for applications where traditional plywood might fall short or when a decrease in product weight or savings in wood raw material are necessary. This report reviews the current progress in fiber-reinforced plywood in the context of plywood as a construction material to better understand the potential gains in plywood applications, mechanical parameters, and material savings. It is found that a simple and cost-effective procedure of fiber reinforcement allows for substantial improvements in plywood's mechanical properties, typically to the extent of 10–40%. It is suggested that the wider adoption of fiber-reinforced plywood, especially in load- and impact-bearing applications, would greatly contribute to enhanced durability and longevity of the material while also allowing for more sustainable use of raw wood material. [ABSTRACT FROM AUTHOR]

Achieving carbon neutrality by 2050 requires extensive energy renovation of the existing building stock. In this study we focus on deep renovation with prefabricated insulation elements as a potential solution to attain the required renovation speed and volume. The use of such elements without a proper moisture safety strategy can, however, lead to moisture-related problems, including mould growth. Here we examine the causes of moisture and mould damage in a case study of a building that has been renovated to near-zero energy standards using prefabricated insulation elements. The study elucidates the reasons for the moisture damages detected and proposes two moisture safety strategies to improve the situation. The first strategy emphasizes the importance of ensuring dry construction conditions by either using a full temporary roof or avoiding rainfall during installation. The second strategy addresses localized water damage to the attic floor and involves the use of protective measures, active ventilation and a correct installation sequence. In the case of local moisture damage, the required amount of ventilation air flow during summer is 0.5-0.55 l/(s·m2). During cooler periods, heating is needed. The employed methods include modelling the case-study building with the IDA Indoor Climate and Energy software, as well as mould growth risk assessment based on temperature and relative humidity measurements. The results highlight the effectiveness of both strategies in preventing mould growth if applied correctly, and emphasize the need for thorough planning, moisture safety regulations and rapid response to ensure successful renovation with prefabricated insulation units. The study provides valuable information on moisture safety strategies for serial renovations with prefabricated elements. The existence and proper implementation of a moisture safety strategy is important for achieving the desired energy performance goals while maintaining building durability and occupant health, and it needs to be applied throughout the chain of site management: from the main contractor down to the skilled worker. [ABSTRACT FROM AUTHOR]

Preserving the built heritage, maintaining the original exteriors of historic apartment buildings, and achieving today's living standards and ambitious environmental objectives require a multidisciplinary approach encompassing cultural, economic, legal, social, environmental and historical factors. This study aims to assess the need for renovation and the cultural and environmental value of historic apartment buildings. Architects, conservators and civil engineers have been involved to evaluate the authenticity of materials and forms, their technical condition and suitability to the historic urban milieu across 19 building components. Our findings reveal significant replacement activities in various elements such as roof coverings, roof eaves, façades, stairwell windows, stairwells, exterior doors, and window and frame distribution, with a particular focus on materials rather than geometry. Notably, there is often a lack of original materials of the windows. When comparing materials and geometries, we observed a higher frequency of material replacement. While the immediate need for intervention may not be urgent, many historic apartment buildings are at risk of imminent material deterioration, necessitating timely renovation. The deep renovation approach, which extends the service life, enhances energy efficiency and indoor climate and restores the exterior aesthetics, offers a threefold benefit. However, aligning the current reconstruction requirements with the preservation of milieu values may remain ambiguous, leading homeowners to resist or overlook these obligations. Consequently, a culture of step-by-step (staged) renovation emerges, contributing to an eclectic appearance of the historically valuable area and promoting the use of inappropriate materials. In conclusion, this research emphasizes the importance of a holistic approach to building renovation, which yields architecturally superior and technically sustainable outcomes. The current study underscores the necessity for a shift in the authorized heritage discourse in Estonia. Rather than primarily imposing restrictive measures on construction and renovation projects, the focus should pivot towards effective communication of historical values. It is crucial to provide support and guidance (not restrictions) to building owners, designers and builders in this regard. [ABSTRACT FROM AUTHOR]

Prefabricated additional insulation elements have demonstrated success in renovating up to 5-storey apartment buildings. However, the unique challenges posed by high-rise buildings necessitate a closer examination of installation and long-term performance. In this study, we developed an additional insulation element specifically tailored for renovating high-rise apartment buildings and analysed its hygrothermal performance. To test the performance of the insulation elements, we installed a prototype and measured its performance at critical points along the external envelope. We calibrated a calculation model and applied building performance simulation software to explore various combinations of prefabricated elements. Our goal was to compare the associated risks and the key hygrothermal properties of these different material combinations within the insulation element. Critical points between the insulation layer and the wind barrier, as well as between the surface of the existing concrete panel wall and the vapour control layer of the additionally insulated exterior wall were analysed. The study's results indicate that the thermal resistance and water vapour permeability of the wind barrier layer, and the presence of an appropriate vapour control layer primarily influence the performance and moisture dry-out of a structure. Additionally, the study results indicate that the weather component has a higher impact than in lower buildings as the wind-driven rain loads are considerably higher in the upper parts of the high-rise buildings. The initial moisture (w = 110 kg/m3 at the height of the 9th storey and w = 117 kg/m3 at the height of the 16th storey) dry-out can last more than 3 years depending on the building type and materials used. This study underscores the importance of tailored solutions and vigilant moisture safety management in high-rise apartment building renovations, particularly when utilizing prefabricated additional insulation elements. [ABSTRACT FROM AUTHOR]

For scaling renovation, there is a need for assessing the energy performance of buildings at the neighborhood level. Traditional methods for assessing individual buildings are manual and time-consuming – not sufficient to enable the neighborhood level assessment of the energy performance of buildings. Instead, new methods based on existing data in national registries and building typologies are required. The aim in this article is to develop for obtaining necessary initial building geometry information for energy performance calculations from the Estonian national Building Registry (EBR), including also Digital Twin (LOD) geometric models of buildings, and the quality and accuracy of this data is assessed. Altogether 417 representative buildings were used for qualitative and quantitative analysis. A sub-sample of 41 buildings were selected for more detailed analysis and development of methods. Two methods were developed to extract and enrich initial building geometry information for energy performance calculations: (a) the method combining the EBR and building reference data; and (b) the method combining the EBR and building typology data and LOD models of apartment buildings. The estimated accuracy of the first method (a) is around 98% and the second method (b) around 94%. Both methods underestimate the actual envelope area and thermal bridge lengths.

Selective demolition of building components and recycling construction demolition waste is a growing tendency as we move towards a circular construction. This study investigates the feasibility of using demolition waste from calcium silicate brick masonry as an aggregate in concrete and mortar. The purpose is to assess its impact on concrete and mortar properties, including compressive strength, durability, and workability. Silicate bricks from two demolished buildings were processed into aggregate, and laboratory experiments were conducted to evaluate concrete and mortar made with varying proportions of recycled aggregate. Results indicate that replacing natural aggregate (limestone rubble and sand) with recycled silicate brick aggregate up to 50% does not significantly compromise concrete performance, with no significant decrease in compressive strength observed. Frost resistance of the concrete made with recycled aggregate even surpasses that of reference concrete, possibly due to the lower density and higher (closed) porosity of the recycled aggregate. However, challenges such as increased water demand and loss of workability over time are noted with higher proportions of recycled aggregate. Further research is recommended to explore strategies for mitigating these challenges and to assess the effects of chemical admixtures on concrete properties. Overall, the findings suggest that recycled calcium silicate brick holds promise as a sustainable alternative for aggregate in concrete production. [ABSTRACT FROM AUTHOR]

The objective of this study was to determine the maximum allowable initial moisture content (MC) for cross-laminated timber (CLT) walls having both exterior and interior thermal insulation. A laboratory test was conducted, for which four test walls with two different insulation solutions and two different MCs were built. Based on the test results, a simulation model was configured and simulations using the model were completed. The simulation results determined that the maximum allowable initial MC of the CLT panels was 17% for walls insulated additionally from inside with mineral wool and 15% for CLT wall assemblies insulated with polyisocyanurate (PIR). Based on these results, it was concluded that the allowable MC ranges between 8% and 16% for construction timber, and therefore, using a PIR board as interior insulation for CLT walls should be undertaken with caution given the very small margin for error in MC. Key words: cross-laminated timber, built-in moisture, interior insulation, mould growth risk. L'objectif de cette etude etait de determiner la teneur maximale admissible en humidite initiale pour les murs de bois lamelle-croise (CLT) a isolant thermique exterieur et interieur. Un essai en laboratoire a ete realise par la construction de quatre murs d'essai avec deux solutions d'isolant differentes et deux teneurs en humidite initiale differentes. Sur la base des resultats des essais, un modele de simulation a ete configure et des simulations a l'aide du modele ont ete realisees. Les resultats de la simulation ont permis de determiner que la teneur initiale maximale en humidite admissible pour des panneaux de CLT etait de 17 % pour les murs isoles egalement de l'interieur avec de la laine minerale (MW) et de 15 % pour les assemblages de murs de CLT isoles avec du polyisocyanurate (PIR). Sur la base de ces resultats, il a ete conclu que, pour le bois de construction, la teneur en humidite admissible varie entre 8 et 16 % et donc utiliser une planche de PIR comme isolant interieur pour les murs en CLT doit etre entrepris avec prudence etant donne la tres faible marge d'erreur quant a la teneur en humidite. [Traduit par la Redaction] Mots-cles: bois lamelle-croise, humidite intrinseque, materiau isolant d'interieur, risque de formation de moisissure., Introduction Because of its low embodied energy, the use of wood for the construction of buildings is a suitable for helping with the decarbonisation of building stock (EPBD 2018). Cross-laminated [...]

This study tests the performance of an EN ISO 13788 occupancy modified model for indoor temperature and humidity in dwellings by comparing the model with the measured indoor temperature and relative humidity in Canada. The performance of ENISO13788 occupancy modified model is tested in 13 outdoor climates and compared with the simplified approach given in the ASHRAE160 standard. It was found that the Estonian model's proposed indoor temperature profile works reasonably well in accordance with the measured indoor temperatures in Vancouver, Canada, which are dependent on the outdoor climate; on the other hand, the ASHRAE 160 indoor temperature profile might not be the best for cold climates. Drawbacks were noted concerning the humidity loads given as a simplified approach in the ASHRAE 160 with the suggestions for the possible future renewal. A new approach for selecting the indoor humidity load for dwellings in cold climates is proposed. Key words: indoor temperature, humidity load, moisture excess, relative humidity, occupancy. Dans le cadre de cette etude, on a teste la performance d'un modele EN ISO 13788 modifie en fonction de l'occupation pour la temperature interieure et l'humidite dans les habitations en comparant le modele a la temperature interieure et a l'humidite relative mesurees au Canada. Les performances du modele EN ISO 13788 modifie selon l'occupation sont evaluees dans 13 climats exterieurs et comparees a l'approche simplifiee de la norme ASHRAE 160. Il a ete constate que le profil de temperature interieure propose par le modele estonien fonctionne raisonnablement bien dans le cadre de temperatures interieures mesurees a Vancouver, au Canada, et dependant du climat exterieur; d'autre part, le profil de temperature interieure ASHRAE 160 n'est peut-etre pas le meilleur pour les climats froids. Des inconvenients ont ete notes concernant les charges d'humidite donnees comme approche simplifiee dans l'ASHRAE 160 de tel sorte que des suggestions ont ete proposees pour le renouvellement futur possible de la norme. Enfin, on propose une nouvelle methode de selection de la charge d'humidite interieure pour les habitations en climat froid. [Traduit par la Redaction] Mots-cles: temperature interieure, charge d'humidite, exces d'humidite, humidite relative, occupation., Introduction Background Indoor hygrothermal loads such as temperature, moisture excess, and (or) relative humidity (RH) affect hygrothermal performance of the building envelope. Proper selection of these indoor boundary conditions is [...]

Despite the growing popularity of wood and wood-based products in the construction industry, there has been insufficient focus on assessing the condition, preservation, and potential reuse of existing timber. While numerous standards evaluate the quality of freshly sawn timber, there is currently no standardized system for assessing the strength properties of aged and reused timber. The lack of these guidelines is also one of the reasons the results obtained in numerous research are often fluctuating, and we cannot draw clear conclusions. The matter is further complicated by the lack of data on old in-situ wood and its exploitation, which would help to evaluate its condition. Consequently, there is a real practical need to assess the condition of old timber to avoid unnecessary demolition and the loss of valuable and structurally sound building material. What sets this study apart from others is that, in addition to destructive testing, the 4-point non-destructive (ND) bending tests were conducted on all four faces of test specimens. This provided an opportunity to assess the wood visually and then find connections to associate external characteristics with real properties. This methodology aimed to determine whether it is feasible to visually assess the most practical way to use wooden elements in construction. If this question arises, which face of the beam would be better suited for the tension side and which for the compression side? The old timber used in testing originated from an old library building located on Vaksali Street, Tartu, Estonia and is estimated to be about 120 years old. This paper investigates and compares the collected data with a Nordic standard for grading fresh-sawn timber and two established Italian standards for visually assessing aged timber. This comparison contributes to developing a standardized framework for future visual assessments. ND and destructive four-point bending tests were performed to validate and find appropriate visual characteristics to determine the strength and stiffness of the timber elements. The primary goals of this study were first to compare the results obtained from existing ND methods with actual results and secondly to provide guidelines for better visual grading of wood in the future, based on Nordic Standard INSTA 142 (2010) and Italian standards UNI 11119 (2004) and UNI 11035 (2010) Contrary to previous research conclusions, the visual assessment results yielded unexpected outcomes. The results show that the grading standards significantly underestimated the real strength of the wood, and even more, none of the visual assessments overestimated the real strength of the specimens. Therefore, based on prior research and the findings derived from this study, there is evident a substantial potential for extensive development and optimization within this field. [ABSTRACT FROM AUTHOR]