Thermal performance of an insulation material is influenced by the in-service temperature condition. Unlike most other insulation materials, thermal resistance (R-value) of polyisocyanurate (polyiso) foam insulation with ‘captive blowing agent’ varies non-linearly with temperature. Building designers consider constant R-value of different insulating materials for building design and energy calculations, and hygrothermal simulation software packages, such as WUFI, consider linear temperature dependent R-value profiles, even for polyiso. However, neither the linear temperature dependent thermal resistance nor the constant thermal resistance value of polyiso represents the actual thermal performance of the building envelope. This thesis aims to quantify the impact of in-service boundary temperature conditions in Canadian climates on the thermal resistance of polyiso foam insulation board used in EPDM and PVC roof constructions. Hygrothermal simulations were performed using WUFI® Pro, which considers real climate data and hygrothermal properties of constituent roof components for evaluating moisture and temperature conditions in roof constructions. Based on heating degree days (HDD), ten different cities were selected between climate Zone 4 (HDD<3000) to Zone 8 (HDD≥7000). The thermal resistance measurements were conducted using heat flow meter apparatus on four polyiso insulation boards (two new and two aged) of different sizes [thickness - new: 1inch (25mm) and 2 inch (51mm); aged: 2 inch (51mm) and 3 inch (76mm)] at five mean temperatures -4°C (25°F), 4.5°C (40°F), 10°C (50°F), 24°C (75°F), 43°C (110°F) and at a temperature differential of 28°C (50°F). The measured thermal resistance data of the four samples at different mean temperatures were normalized with calculated thermal resistance of each sample at 22°C (72°F). The normalized R-value variation was calculated using in-service boundary temperature conditions determined from hygrothermal simulations and considering linearly varied thermal resistance with temperature, for the selected ten Canadian cities. / Graduate

The hygrothermal analysis of building envelopes plays a crucial role in the renovation strategies for historical buildings. Dynamical hygrothermal simulations under realistic conditions are effective in predicting moisture-related damages, including the risk of mold growth or frost damage, which can arise when combining historical walls with modern insulation systems. However, accurately modeling and simulating historic walls, composed of brick/stone and mortar joints, using detailed two- or three-dimensional models, is a complex and time-consuming task. As a result, a common practice in hygrothermal simulations is to simplify old masonry into a one-dimensional layer of stone/brick, disregarding mortar joints. Nonetheless, in this study cases were identified where this simplification approach leads to unacceptable inaccuracies, particularly when historic masonry is combined with vapor-tight insulation systems. Also, this study investigated the influence of the internal geometry of mortar joints and the stone/mortar ratio in hygrothermal simulations. While the internal disposition of joints showed minimal influence, the stone/mortar ratio was found to play a significant role. In light of these findings, this thesis proposes a method to replace the complex representation of historical masonry with a fictitious homogenized porous material that incorporates the influence of mortar joints. The hygrothermal properties of this newly developed ‘Homogenized Porous Material’ are averaged and optimized to closely approximate the behavior of the hygrothermal model for important applications. The proposed method was applied to various combinations of mortars, stones, and bricks. Furthermore, the behavior of the ‘Homogenized Porous Material’ was evaluated under dynamic conditions, specifically for the case of an internally insulated wall in different climates. A comparison was made with a two-dimensional fully described model to assess the performance of the developed method. The results demonstrate considerable improvements compared to the conventional one-dimensional stone/brick layer approximation, with the degree of improvement being more pronounced when the hygrothermal properties of the stone/brick and mortar differ significantly. The developed method offers significant advantages: for example, the application to 3D building energy simulation tools which entangle moisture balances, allows for quick pre-checks for moisture damage. This can help pre-assessing the potential risks of moisture-related issues in a time-efficient manner also at building component level. Moreover, in time-critical studies where a large number of variant analyses are required, 1D models remain essential as they allow for efficient sensitivity analyses with a large number of simulations runs. This method facilitates a comprehensive exploration of different scenarios and parameter variations, aiding in the identification of critical factors affecting the hygrothermal performance of historic walls. Furthermore, the developed method has potential applications in situations where the inner structure of walls is unknown, such as forensic analysis of historical constructions. By providing a reliable and simplified representation of the hygrothermal behavior, this method can support investigations and assessments of moisture-related issues in historical buildings, even when detailed knowledge of the internal structure is limited. In conclusion, this research can offer to architects and engineers practical benefits in terms of accurate prediction of moisture-related damages, efficient pre-checks, sensitivity analyses, and applications in cases with limited knowledge of wall structures. In future, an extended database of ‘Homogenized Porous Materials’, suitable to model masonry walls, can be built for the users.:Preface Abstract Kurzfassung Table of Contents Chapter 1 - Introduction and overview 1.1 Motivation 1.2 Problem statement 1.3 Thesis 1.4 Solution strategy and methodology 1.5 Structure of the study Chapter 2 - Literature background 2.1 General concepts concerning historical masonry 2.2 Theory and tool for hygrothermal simulations 2.2.1 Balance equation of energy and mass for the porous medium 2.2.2 Flux of energy and mass for the porous medium 2.2.3 Climate and boundary conditions Incident wind-driven rain Radiation, short-wave and long-wave Interior climate 2.3 Main hygrothermal properties of materials and experimental measurement procedures 2.3.1 Bulk density and porosity: helium pycnometer 2.3.2 Specific heat capacity: calorimeter 2.3.3 Thermal conductivity: the hot plate measurement 2.3.4 Vapour conductivity: the cup-tests 2.3.5 Moisture storage function: desiccator method and pressure plates 2.3.6 Liquid conductivity: water uptake and drying experiment 2.3.7 Vapor and liquid conductivity function: capillary condensation redistribution test (CCR) 2.4 Complexity and simplification for the hygrothermal modeling and simulation of historical masonry Chapter 3 - Quantifying the Impact of Mortar Joints in Hygrothermal Simulations of Historical Masonry 3.1 Investigation through dynamical hygrothermal simulation in realistic condition 3.2 Evidence of mortar joints’ impact in hygrothermal simulations of historic walls 3.3 Dependence of the hygrothermal transport of a masonry wall on its internal geometry 3.4 Discrepancies due to assumptions on stone/mortar ratio 3.5 The case of a three-dimensional simulation Chapter 4 - A fictitious ‘Homogenized Porous Material’ (HPM) to describe heat and moisture transport in a massive historic wall 4.1 Definition of the preliminary activities: choice of the reference model and of the materials 4.2 Homogenized porous material characterization 4.2.1 Phase 1: hygrothermal properties through analytical calculation Bulk density, ρ Porosity, θpor Specific heat capacity, Cp Moisture storage function, θl,HPMpc 4.2.2 Phase 2: hygrothermal properties through numerical experiment Dry Thermal conductivity, λdry Thermal conductivity function, λ(θl) Dry water vapour resistance factor, μdry Water vapour conductivity function, Kv(θl) 4.2.3 Phase 3: hygrothermal properties through optimization algorithm 4.3 Conclusions on the developed method Chapter 5 - Application of the ‘Homogenized Porous Material’ (HPM) method 5.1 Preliminary activities and reading instructions 5.2 Homogenized Porous Material characterizations in three phases 5.3 Dynamical hygrothermal simulation in realistic condition with Homogenized Porous Materials 5.3.1 Simulations set-up 5.3.2 Analyzed Output 5.3.3 Result of the simulation in realistic design condition with Interior Insulation 5.4 Discussion on the obtained results 5.4.1 Discussion on HPM calibration results 5.4.2 Discussion on HPM dynamical hygrothermal simulation in realistic condition 5.5 Conclusions on the tests Chapter 6 - Summary, conclusions and outlooks 6.1 Content summary 6.2 Achievements and conclusions 6.3 Future prospects Appendix I List of Figures (Appendix I) List of Tables (Appendix I) Appendix II List of Figures (Appendix II) Appendix III List of figure (Appendix III) List of Tables (Appendix III) List of Abbreviations and Symbols List of Figures List of Tables Acknowledgements Bibliography

Thermal resistance per unit thickness for Vacuum Insulation Panel (VIP) is 5 to 10 times higher than conventional insulation materials. This makes VIP an attractive option for retrofitting exterior building envelopes. Insulation can be added in an exterior wall either on the interior side, exterior side or in the available stud cavity. VIP has high vapor diffusion resistance factor and could lead to moisture management risk in the wall layers because of the steep temperature gradient in the wall generated due to very high thermal resistance of VIP. VIP is a relatively new insulation material for building envelope construction, thus the hygrothermal or moisture management performance of VIP-insulated exterior building envelopes need to be critically analyzed before its application. This study aims to evaluate the moisture management risk associated with wood-frame stucco-cladded exterior walls retrofitted with VIP using a 2-D hygrothermal simulation tool WUFI-2D. Eight North American locations were considered, based on Moisture Index (MI) which varied between 0.13 and 1.17, and two different indoor hygrothermal loading conditions as prescribed by the ASHRAE 160P and EN 13788, respectively. The outputs from hygrothermal simulations (water content, relative humidity and temperature) were critically analysed and expressed further using freeze-thaw cycles and RHT indices. The results show that the appropriately designed VIP retrofitted walls can have superior moisture management performance as compared to conventional stucco-cladded wall. / Graduate