This study focuses on the hygrothermal performance of Moso bamboo. The knowledge in this aspect is remarkable important for the research of building energy saving and the low carbon building design. However, the detailed hygrothermal properties of Moso bamboo are fairly rare. To obtain these data, a series of experimental works have been done for measurement of density, porosity, thermal conductivity, specific heat capacity, water vapour permeability, hygrothermal expansion and sorption isotherm of Moso bamboo. To obtain further understanding on the hygrothermal performance of Moso bamboo, a number of dynamic heat and moisture transfer experiments were conducted. These experiments simulated two extreme outdoor environments and one indoor environment. The temperature and RH responses of Moso bamboo panels were monitored. Then a coupled transient heat and moisture transfer numerical simulation at the material level was conducted to predict and validate the hygrothermal performance of Moso bamboo. A sensitivity study of the hygrothermal properties of bamboo was also presented to indentify the influence of each hygrothermal property of Moso bamboo. Major findings include the following aspects. Both experiment and simulation results appear to be consistent with the results of measurements of the basic hygrothermal parameters. The parametric study found that density can be regarded as the most sensible parameter to influence the temperature simulation results at the transient state, while the thermal conductivity dominated the temperature variation at the steady state. The water vapour diffusion resistance factor can be regarded as the most critical parameter to influence the RH simulation results. The influence of liquid water diffusivity is negligible in this study. The parametric study results indicated that the simulation with moisture is more accurate than the simulation without moisture in both equilibrium and transient state. The results also imply that the existence of moisture could increase the heat capacity and reduce the thermal conductivity. The results of this study recommend that the external part of the bamboo culm wall can be utilised to minimise the RH variation of the panel while the internal part of the bamboo culm wall is suitable to increase the thermal insulation performance of the panel. To avoid hygroexpansion, the implementation of external part of bamboo culm wall needs to be minimised.

Roofs are the single enclosure element common to artificial shelters constructed by all cultures in all climate regions. The hygrothermal performance of insulated, sloped, wood-framed roof assemblies has long been of interest to building scientists and building codes alike. Requirements for the ventilation of roof assemblies have been included in building codes for more than 50 years, however moisture problems still occur. Unvented roof assemblies have been suggested as an alternate and potentially superior solution. While unvented roofs have become relatively common in the warmer southern climates of North America, some technical issues remain unclear and the need exists for further study and demonstration of the hygrothermal performance of both ventilated and unvented roof assemblies in cold northern climates. This thesis seeks to address these issues through a review of existing literature, experience and industry practice, field investigation and measurement, analytical calculation and computer simulations.

Roofs are the single enclosure element common to artificial shelters constructed by all cultures in all climate regions. The hygrothermal performance of insulated, sloped, wood-framed roof assemblies has long been of interest to building scientists and building codes alike. Requirements for the ventilation of roof assemblies have been included in building codes for more than 50 years, however moisture problems still occur. Unvented roof assemblies have been suggested as an alternate and potentially superior solution. While unvented roofs have become relatively common in the warmer southern climates of North America, some technical issues remain unclear and the need exists for further study and demonstration of the hygrothermal performance of both ventilated and unvented roof assemblies in cold northern climates. This thesis seeks to address these issues through a review of existing literature, experience and industry practice, field investigation and measurement, analytical calculation and computer simulations.

Thermal improvement of traditional and historic buildings is going to play a crucial role in the achievement of established carbon emission targets. The suitable retrofit options for traditional buildings are, however, very limited and their long term performance is still uncertain. Evaluation of risks, prior to any alteration of building physics, is critical to avoid future damage to the fabric or occupants’ health. Moisture dynamics in building envelopes are affected by the enclosure’s geometry, materials properties and external and internal boundary conditions. Since the internal boundary is heavily influenced by users, understanding their behaviour is essential to predict the outcome of energy retrofit measures more accurately. The effect of user behaviour on energy demand has been extensively investigated; however, its impact on the hygrothermal performance of the envelopes has barely been explored. This research approached the connection between users and buildings from a new angle looking at the effect that user behaviour has on moisture dynamics of buildings’ envelopes after the retrofit. Qualitative and quantitative research methods were used to develop a holistic evaluation of the question. Firstly, factors influencing the adoption of energy efficiency measures in traditional buildings were explored by means of semi-structured interviews with private owners and project managers. Subsequently, a multi-case study including interviews with occupants and monitoring of environmental conditions was conducted. Data collected at this stage was used to explore users’ daily practices of comfort and to characterise the internal climate of traditional dwellings. Lastly, users’ impact was quantified using Heat, Air and Moisture (HAM) numerical simulation. This allowed for the evaluation of the hygrothermal performance of walls under different internal climate scenarios. Combined results of interviews, environmental monitoring and simulation showed that internal climate can compromise envelope performance after the retrofit and highlighted the need to consider users in the decision making process. Ultimately, the results of this research will help to increase awareness about the potential impact of user behaviour and provide recommendations to decision makers involved in the energy retrofit of traditional structures.

Recentemente foram aprovadas normas para requisitos e critérios de desempenho térmico de habitações de interesse social. Estas normas são importantes para a melhoria do desempenho térmico dessas habitações no Brasil. No entanto, a abordagem adotada é geral no que diz respeito às regiões bioclimáticas brasileiras e a análise é feita para sistemas da edificação (aberturas, paredes, cobertura) isoladamente, o que pode não expressar o comportamento térmico para determinadas condições climáticas. O presente estudo apresenta uma proposta de método de avaliação de desempenho higrotérmico de habitações térreas unifamiliares de interesse social para condições climáticas de Porto Alegre, RS, que visa à avaliação global da edificação através de requisitos e critérios que complementam aqueles propostos pelas normas e que sejam de fácil aplicação pelos envolvidos no processo de produção de habitações de interesse social. Considera-se a possibilidade de condensação sobre superfícies internas da edificação, coeficientes volumétricos globais de perda e ganho de calor através de sua envolvente, inércia térmica, entre outros, obtidos da literatura e da análise de quatro habitações construídas em Porto Alegre, duas submetidas a medições in loco e duas consideradas como referência para habitação de interesse social para as condições econômicas e culturais do público-alvo, segundo agentes ligados ao setor em Porto Alegre. O método foi submetido à opinião de agentes, envolvidos com o financiamento, projeto, execução, fiscalização e avaliação de habitações de interesse social em Porto Alegre, e a especialistas da área de conforto térmico atuando em instituições de ensino e pesquisa nacionais. São indicados três graus de qualidade que podem ser atingidos pelas habitações, de acordo com a disponibilidade de recursos para a construção da habitação. O método pode ser uma ferramenta auxiliar na tomada de decisão no processo de projeto, aprovação e avaliação de habitações de interesse social pelos agentes públicos ligados ao setor. / Recently, low cost housing thermal performance standards were developed and approved in Brazil. These standards establish requirements and criteria that low cost housing must satisfy. However, the approach used generally deals with climatic conditions and the evaluation is based on analysis of individual components. This approach cannot express the real thermal behaviour of housing. This study presents a thermal performance evaluation method for low cost single-family one-floor housing considering the climatic conditions of Porto Alegre, Brazil. The method aims toward a global evaluation of housing through requirements and criteria that complement the standards approved recently and it considers mathematical procedures that can be easily applied by government agents involved in this task. Inner surface condensation, global flow heat coefficients, thermal inertia, among others, obtained from literature, are proposed. Four low cost houses built in Porto Alegre, considered to be references according to social and economic local reality, were evaluated through the method. Government agents involved in the project, design, financing, building, overseeing and evaluation of low cost housing in Porto Alegre and experts from research institutes in Brazil also gave their opinions of the method. Three degrees of performance for housing, in accordance with availability of government resources, are defined. The method can be used as an evaluation of possible solutions, thereby aiding decision makers.

Recentemente foram aprovadas normas para requisitos e critérios de desempenho térmico de habitações de interesse social. Estas normas são importantes para a melhoria do desempenho térmico dessas habitações no Brasil. No entanto, a abordagem adotada é geral no que diz respeito às regiões bioclimáticas brasileiras e a análise é feita para sistemas da edificação (aberturas, paredes, cobertura) isoladamente, o que pode não expressar o comportamento térmico para determinadas condições climáticas. O presente estudo apresenta uma proposta de método de avaliação de desempenho higrotérmico de habitações térreas unifamiliares de interesse social para condições climáticas de Porto Alegre, RS, que visa à avaliação global da edificação através de requisitos e critérios que complementam aqueles propostos pelas normas e que sejam de fácil aplicação pelos envolvidos no processo de produção de habitações de interesse social. Considera-se a possibilidade de condensação sobre superfícies internas da edificação, coeficientes volumétricos globais de perda e ganho de calor através de sua envolvente, inércia térmica, entre outros, obtidos da literatura e da análise de quatro habitações construídas em Porto Alegre, duas submetidas a medições in loco e duas consideradas como referência para habitação de interesse social para as condições econômicas e culturais do público-alvo, segundo agentes ligados ao setor em Porto Alegre. O método foi submetido à opinião de agentes, envolvidos com o financiamento, projeto, execução, fiscalização e avaliação de habitações de interesse social em Porto Alegre, e a especialistas da área de conforto térmico atuando em instituições de ensino e pesquisa nacionais. São indicados três graus de qualidade que podem ser atingidos pelas habitações, de acordo com a disponibilidade de recursos para a construção da habitação. O método pode ser uma ferramenta auxiliar na tomada de decisão no processo de projeto, aprovação e avaliação de habitações de interesse social pelos agentes públicos ligados ao setor. / Recently, low cost housing thermal performance standards were developed and approved in Brazil. These standards establish requirements and criteria that low cost housing must satisfy. However, the approach used generally deals with climatic conditions and the evaluation is based on analysis of individual components. This approach cannot express the real thermal behaviour of housing. This study presents a thermal performance evaluation method for low cost single-family one-floor housing considering the climatic conditions of Porto Alegre, Brazil. The method aims toward a global evaluation of housing through requirements and criteria that complement the standards approved recently and it considers mathematical procedures that can be easily applied by government agents involved in this task. Inner surface condensation, global flow heat coefficients, thermal inertia, among others, obtained from literature, are proposed. Four low cost houses built in Porto Alegre, considered to be references according to social and economic local reality, were evaluated through the method. Government agents involved in the project, design, financing, building, overseeing and evaluation of low cost housing in Porto Alegre and experts from research institutes in Brazil also gave their opinions of the method. Three degrees of performance for housing, in accordance with availability of government resources, are defined. The method can be used as an evaluation of possible solutions, thereby aiding decision makers.

Recentemente foram aprovadas normas para requisitos e critérios de desempenho térmico de habitações de interesse social. Estas normas são importantes para a melhoria do desempenho térmico dessas habitações no Brasil. No entanto, a abordagem adotada é geral no que diz respeito às regiões bioclimáticas brasileiras e a análise é feita para sistemas da edificação (aberturas, paredes, cobertura) isoladamente, o que pode não expressar o comportamento térmico para determinadas condições climáticas. O presente estudo apresenta uma proposta de método de avaliação de desempenho higrotérmico de habitações térreas unifamiliares de interesse social para condições climáticas de Porto Alegre, RS, que visa à avaliação global da edificação através de requisitos e critérios que complementam aqueles propostos pelas normas e que sejam de fácil aplicação pelos envolvidos no processo de produção de habitações de interesse social. Considera-se a possibilidade de condensação sobre superfícies internas da edificação, coeficientes volumétricos globais de perda e ganho de calor através de sua envolvente, inércia térmica, entre outros, obtidos da literatura e da análise de quatro habitações construídas em Porto Alegre, duas submetidas a medições in loco e duas consideradas como referência para habitação de interesse social para as condições econômicas e culturais do público-alvo, segundo agentes ligados ao setor em Porto Alegre. O método foi submetido à opinião de agentes, envolvidos com o financiamento, projeto, execução, fiscalização e avaliação de habitações de interesse social em Porto Alegre, e a especialistas da área de conforto térmico atuando em instituições de ensino e pesquisa nacionais. São indicados três graus de qualidade que podem ser atingidos pelas habitações, de acordo com a disponibilidade de recursos para a construção da habitação. O método pode ser uma ferramenta auxiliar na tomada de decisão no processo de projeto, aprovação e avaliação de habitações de interesse social pelos agentes públicos ligados ao setor. / Recently, low cost housing thermal performance standards were developed and approved in Brazil. These standards establish requirements and criteria that low cost housing must satisfy. However, the approach used generally deals with climatic conditions and the evaluation is based on analysis of individual components. This approach cannot express the real thermal behaviour of housing. This study presents a thermal performance evaluation method for low cost single-family one-floor housing considering the climatic conditions of Porto Alegre, Brazil. The method aims toward a global evaluation of housing through requirements and criteria that complement the standards approved recently and it considers mathematical procedures that can be easily applied by government agents involved in this task. Inner surface condensation, global flow heat coefficients, thermal inertia, among others, obtained from literature, are proposed. Four low cost houses built in Porto Alegre, considered to be references according to social and economic local reality, were evaluated through the method. Government agents involved in the project, design, financing, building, overseeing and evaluation of low cost housing in Porto Alegre and experts from research institutes in Brazil also gave their opinions of the method. Three degrees of performance for housing, in accordance with availability of government resources, are defined. The method can be used as an evaluation of possible solutions, thereby aiding decision makers.

Drywall board-based structures, a competent and cost-effective method of providing flexible partitioning assemblies in commercial and residential houses, are now widely used as walls or ceilings. However, the gypsum-based drywall that has been used in construction is not water-resistant and can create problems such as mold growth and structural defects. The aim of this study is 1) to develop a new sandwich panel with better physical and mechanical properties using locally sourced materials 2) to investigate the long-term hygrothermal performance of the new sandwich panel through using a numerical simulation. The sandwich panel is composed of two different thicknesses of kraft-paper honeycomb core bonded to two cementitious panels with silicone-based adhesive. The experimental results show that the sandwich panel with a thicker core has lower thermal conductivity and higher flexural strength compared to the gypsum-based drywall. The heat and moisture performance of two wall structures were performed using the WUFI Pro simulation program. The results of the modeling analysis present that wall assembly with gypsum-based drywall has higher water content than multilayer sandwich panel. In addition, the multilayer sandwich panel shows a 4.6% lower annual heat flow compared to the reference wall.

Cross-laminated timber (CLT) is an emerging sustainable engineered material with unique properties that in many ways make it superior to conventional construction material. CLT was invented in the 1990s and the volume produced have increased worldwide since then. It can be used in the load bearing structure for walls and floor slabs in the different typologies, e.g. residential and office buildings.The hygroscopic nature of wood allows it to exchange moisture with the surrounding environment. This may lead to an alteration of properties of wood-based materials such as CLT and can be accompanied by deformations and stresses. These effects influence the CLT’s structural stability, durability and safety.This study focuses on the consequences of moisture content variations in CLT structures, including mechanical properties like modulus of elasticity and bending stiffness (EI). Temperature and relative humidity were measured over three years in three positions along the thickness direction of a slab element on the first floor of House Charlie, a four-storey timber office building located in Växjö, Sweden.The investigation was carried out by mathematical modelling applying MATLAB® software aiming to find the moisture content as a function of time and thickness from the real-world data of House Charlie. The focus was on determining changes in modulus of elasticity and bending stiffness in response to moisture variation. The results showed that the moisture content within a slab of the building varied periodically following the seasonal variation throughout the years. The moisture content at the bottom of the slab was significantly lower compared to two other positions. According to the linear regression analysis, a linear relationship between the moisture content (MC) and positions across the CLT slab at each time step was defined. High R2 values, above 0.9, show the goodness of the fitted model. Applying the MC as a function of time and thickness into an available relationship of modulus of elasticity (E) could predict stiffness versus varied MC in the next step. The modulus of elasticity decreased with an increase in the moisture content over the studied period with a higher variation range at the bottom of the slab. In the final step, bending stiffness was assessed as a function of the changed moisture content. Bending stiffness increased periodically over time, attributed to overall more dry-out of the slab with time.The reported results of the present study give new insight into the behaviour of CLT structure over longer time periods. The recurring pattern in alterations stems from the reliance of bending stiffness on the modulus of elasticity function, which is in turn influenced by the linear relationship with moisture content exhibiting cyclic characteristics. The minimum and maximum values for EI were 3.5×1012 Nmm2 and 3.71×1012 Nmm2, respectively, a variation of approximately ±2.5% around the average. As the time steps increased, the bending stiffness also increased, given the progressive growth of the modulus of elasticity over time.

The Intergovernmental Panel on Climate Change (IPCC) estimates that buildings account for 40% of the global energy use. The IPCC believes substantial improvements to building efficiency can be implemented easily by improving building enclosures through increased levels of insulation, optimizing glazing areas and minimizing infiltration of outside air.<br><br> Building enclosure design encompasses a wide range of parameters but the transport of heat, air and moisture through the enclosure is of primary importance. In predominantly cold Canadian climates, adequate thermal insulation, effective air barriers, and proper moisture control are crucial for energy savings and durability of the structure.<br><br> For decades, standard construction practice in Canada dictated a polyethylene sheet behind the interior drywall layer to serve as a vapour barrier for assemblies with traditional fibre-based cavity insulation. If the polyethylene sheet was sealed carefully enough it had the added benefit of reducing air leakage. Unfortunately, vapour barriers place the emphasis on the wrong moisture transport mechanism; air leakage can have 10 times or greater the wetting potential than vapour diffusion. Regardless, code enforcement personnel continued (and continue in some areas) to require vapour barriers in all climates, all assemblies, and all occupancies. To do so, they overrule the provision in Part 5 of The National Building Code of Canada that states vapour barriers are not required if it can be shown that the uncontrolled vapour diffusion will not affect the operation of the building and systems, or the health and safety of the occupants.<br><br> Foam plastic insulations perform better than fibre-based insulation in terms of the combined resistance to transmission of heat, air and vapour. This research investigated several types of open cell and closed cell spray polyurethane foam insulation in a variety of assembly configurations both in lab tests and hygrothermal simulations. The simulations were extrapolated to seven Canadian climate categories and three levels of interior relative humidity. The goal was to determine which spray polyurethane foam applications required the addition of a dedicated vapour barrier layer beyond what the foam itself could provide.<br><br> The moisture content of the oriented strand board sheathing layer (OSB) in the tested and modelled assemblies was used as the performance evaluation point because during wintertime vapour drives, the wood sheathing is the most likely condensing surface. Prolonged high moisture content (greater than 20%) in wood and wood products in wall assemblies leads to mould growth and decay. By this measure, if the wood sheathing moisture contents stay within the safe range (less than 19%) a vapour barrier is not necessary. The results are presented in Table 7-4.<br><br> The performance of assemblies containing closed cell spray foam was excellent for all climates and humidity levels. Their performance was equivalent to traditional wall assemblies incorporating a polyethylene sheet vapour barrier. The performance of assemblies with open cell spray foam was equivalent to traditional wall assemblies containing no vapour barrier. Open cell spray foam and fibreglass batt both require additional vapour control layers with all but the mildest Canadian climates with the lowest interior humidities. However, in those mild climates with low interior humidities, the only vapour control layer required was a medium permeance latex paint with primer.<br><br>