scholarly journals Preliminary investigation on the transient hygrothermal analysis of a CLT-based retrofit solution for exterior walls

2021 ◽  
Vol 2042 (1) ◽  
pp. 012142
Author(s):  
V Costanzo ◽  
G Evola ◽  
L Marletta ◽  
G Roccella
Keyword(s):  
Preliminary Investigation ◽  
Mould Growth ◽  
Total Water ◽  
Liquid Form ◽  
Water Vapour Diffusion ◽  
Hygrothermal Performance ◽  
Funded Project ◽  
Hygrothermal Analysis ◽  
Wall Assembly ◽  
Different Climates

Abstract This paper investigates the transient hygrothermal performance of an innovative energy and seismic renovation solution for reinforced concrete (RC) framed buildings, based on the addition of Cross-Laminated Timber (CLT) panels to the outer walls, in combination with wood-based insulation. This solution is being developed in the framework of a four-year EU-funded project called e-SAFE. The investigation relies on numerical simulations in DELPHIN 6.1, by considering combined heat and mass transfer (HAMT) due to water vapour diffusion and capillary transport. The proposed solution is tested in three different climates in Italy, to verify whether the CLT layer and the outer waterproof vapour-open membrane, inserted to protect the wood-based insulation from rain, still allow the effective drying of the vapour accumulated in liquid form in the walls, while also preventing mould formation. The results show that the increased thermal resistance of the wall assembly significantly reduces the total water content, although moderate risks of mould growth in the wooden materials may occur in coldest climates.

A comparison of hygrothermal simulation results derived from four simulation tools

2021 ◽  
pp. 174425912098876
Author(s):  
Maurice Defo ◽  
Michael Lacasse ◽  
Abdelaziz Laouadi
Keyword(s):  
Relative Humidity ◽  
Outer Layer ◽  
Growth Index ◽  
Mould Growth ◽  
Simulation Tools ◽  
Assembly Design ◽  
Hygrothermal Simulation ◽  
Moisture Performance ◽  
Wood Frame ◽  
Wall Assembly

The objective of this work was to compare the hygrothermal responses and the moisture performance of four wood-frame walls as predicted by four hygrothermal (HAM) simulation tools, namely: DELPHIN, WUFI, hygIRC and COMSOL. The four wall systems differ only in their cladding type; these were fibreboard, vinyl, stucco and brick. Three Canadian cities having different climates were selected for simulations: Ottawa, Ontario; Vancouver, British Columbia and Calgary, Alberta. In each city, simulations were run for 2 years. Temperature and relative humidity of the outer layer of OSB sheathing were compared amongst the four simulation tools. The mould growth index on the outer layer of the OSB sheathing was used to compare the moisture performance predicted by the respective hygrothermal simulation tools. Temperature profiles of the outer layer of the OSB sheathing were all in good agreement for the four HAM tools in the three locations. For relative humidity, the highest discrepancies amongst the four tools were found with stucco cladding where differences as high as 20% could be found from time to time. Mould growth indices predicted by the four HAM tools were similar in some cases but different in other cases. The discrepancies amongst the different HAM tools were likely related to: the material property processing, how the quantity of wind-driven rain absorbed at the cladding surface is computed and some implementation details. Despite these discrepancies, The tools generally yielded consistent results and could be used for comparing the impacts of different designs on the risk of premature deterioration, as well as for evaluating the relative effects of climate change on a given wall assembly design.

scholarly journals Sensitivity analysis of hygrothermal performance of wood framed wall assembly under different climatic conditions: the impact of cladding properties

2021 ◽  
Vol 2069 (1) ◽  
pp. 012010
Author(s):  
Chetan Aggarwal ◽  
Lin Wang ◽  
Maurice Defo ◽  
Hua Ge ◽  
Max Junginger ◽  
...  
Keyword(s):  
Material Properties ◽  
Growth Index ◽  
Climatic Conditions ◽  
Climate Zones ◽  
Liquid Diffusivity ◽  
Hygrothermal Performance ◽  
Moisture Performance ◽  
Wall Assembly ◽  
The Impact ◽  
Cladding Material

Abstract One of the parameters that influences the moisture performance of the wood framed wall assembly is the material properties of exterior cladding. The uncertainties of its properties, would result in a range of wall performance. The objective of this study was to investigate the impact of uncertainties in cladding material properties on moisture performance of wood framed wall assembly under different climatic conditions. A wood framed (2×6 wood stud) wall with exterior brick cladding was simulated assuming 1% rain leakage deposited on the exterior side of sheathing membrane. A parametric study was carried out to analyze the impact of the cladding properties on the moisture response of OSB. The simulations were conducted in five different cities located in different climate zones across Canada. The aim was to identify the most influential cladding property on the moisture response of OSB, i.e., mould growth index and moisture content, to the varying cladding properties under different climatic conditions i.e., different cities under historical and future conditions. In general, it was found that liquid diffusivity is the parameter that has the most influence on moisture response of OSB in all the five cities. Also, the significance of this influence varies depending on the climatic conditions.

scholarly journals Hygrothermal performance of the building envelope with low environmental impact: case of a hemp concrete envelope

2021 ◽  
Vol 2069 (1) ◽  
pp. 012006
Author(s):  
A Kabore ◽  
W Maref ◽  
C O Plamondon
Keyword(s):  
Environmental Impact ◽  
Air Conditioning ◽  
Energy Performance ◽  
Building Envelope ◽  
Glass Wool ◽  
Mould Growth ◽  
Cement Block ◽  
Hygrothermal Performance ◽  
The City

Abstract This document is a case study of hemp-based materials integrated into the building envelope for African and North American’s applications. The objective is to evaluate the energy performance of hemp concrete for construction in Montreal, Canada, where heating predominates and in Dori, Burkina Faso, where air conditioning predominates. The effect of thermal and hygrothermal comfort of hemp concrete, glass wool, cement block and compressed earth brick walls were simulated to quantify the benefits on overheating during the hottest months for the city of Dori and the risk of mould growth in the walls of the building in winter for the city of Montreal.

scholarly journals Parametric study on the hygrothermal performance of timber frame walls with external airtightness membranes in a temperate maritime climate

2019 ◽  
Vol 282 ◽  
pp. 02080
Author(s):  
Valentina Marincioni ◽  
Federico Lorenzetti ◽  
Hector Altamirano-Medina
Keyword(s):  
Parametric Study ◽  
Indoor Environment ◽  
Moisture Transfer ◽  
Wall Structure ◽  
Two Dimensional ◽  
Mould Growth ◽  
Timber Frame ◽  
Maritime Climate ◽  
Hygrothermal Performance ◽  
Control Layer

In recent years, external airtightness membranes have become an option for timber frame wall systems, as they allow high levels of air- and wind-tightness with an easy installation and provide rainwater protection during construction. This opens up the option of removing the internal air and vapour control layer. However, the hygrothermal risks associated to this option could be higher than in conventional construction, because vapour transfer can occur from the indoor environment into the timber frame wall not just via diffusion but also advection. This can lead to moisture accumulation and mould growth risk within the wall structure. This paper presents a parametric study that aims at identifying the moisture risk when external airtightness membranes are installed on a timber frame wall in a temperate maritime climate. The parametric study considered the two-dimensional heat, air and moisture transfer within a timber frame wall. Parameters having higher influence on moisture risk were identified and should be considered when designing robust wall systems.

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