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The purpose of this paper is to propose a methodology for evaluating the hygrothermal performance of framed wall assemblies based on design limits. This methodology allows designers to evaluate wall assemblies based on their absolute performance rather than relative performance which is typically done for most hygrothermal analysis.

The approach in developing this methodology was to evaluate wall assemblies against three typical design loads (e.g. air leakage, construction moisture, rain penetration) and determine limits in minimum insulation ratio, maximum indoor humidity and maximum rain penetration rates. This analysis was performed at both the field area of the wall and at framing junctions such as window sills.

The findings in this paper shows example design limits for various wall assemblies in heating-dominated climates in North America. Design limits for wall assemblies with moisture membranes of different vapour permeance are provided for both the field area of the wall and at window sills. Discussions about the importance of 2D hygrothermal simulation and performance of vapour permeable sub-sill membranes are also provided.

This framework of hygrothermal analysis will enable designers to make better decisions when designing framed wall assemblies suitable to the local climate and interior specifications for their projects. It will also enable the development of a design tool that will allow designers to visually see the implications of certain design decisions and filter out designs that do not meet their design conditions.

The residential sector in Ireland accounted for 25 per cent of energy related CO2 emissions in 2016 through burning fossil fuels, a major contributor to climate change. In support of Ireland’s CO2 reduction targets, the existing housing stock could contribute greatly to the reduction of space-heating energy demand through retrofit. Approximately 50 per cent of Ireland’s 2m dwellings pre-date building regulations and are predominantly of cavity and solid wall construction, the performance of which has not been extensively investigated at present. Although commitment to thermal upgrade/retrofit of existing buildings may increase under future government policies, the poor characterisation of actual thermal performance of external walls may hinder the realisation of these targets. Thermal transmittance (U-values) of exterior walls represents a source of uncertainty when estimating the energy performance of dwellings. It has been noted in research that the standard calculation methodology for thermal transmittance should be improved. Implementing current U-value calculation methods may result in misguided retrofit strategies due to the considerable discrepancies between in situ measurements and calculated wall U-values as documented in the case studies carried out in this research. If the method of hygrothermal analysis were to be employed as a replacement for the current standard calculation, it could have significant implications for policy and retrofit decision making. The paper aims to discuss this issue.

This research project analysed a case study situated in Dublin, Ireland. The case studies offer an account of the in situ thermal transmittance of exterior walls and link these to hygrothermally simulated comparisons along with more traditional design U-values.

The findings of this research identify discrepancies between in situ and design U-values, using measurement, hygrothermal simulation and standard method U-value calculations. The outcomes of the research serve as an introduction to issues emanating from a larger research project in order to encourage researchers to understand and further explore the topic.

It has previously been highlighted that moisture content is linked to the increase in thermal conductivity of building materials, thus reducing the thermal effectiveness and increasing the elemental U-value. Therefore, it is vital to implement reliable prediction tools to assess potential thermal performance values. This paper presents the findings of a critical instance case study in Dublin, Ireland in which an existing west facing external wall in a semi-detached dwelling was analysed, simulated and measured to verify the elemental wall assembly and quantify thermal transmittance (U-value) incorporating the major criteria required for building performance simulation.

The purpose of this study is to investigate the effect of panel connections on the hygrothermal performance of facade panels using a coupled, transient heat and moisture transfer analysis.

A coupled, transient heat and moisture transfer analysis has been conducted to investigate the effect of panel connections in the hygrothermal behavior of facade panels. Governing partial differential equations for the coupled heat and moisture transfer were formulated. Four panel connections proposed by pre-cast/pre-stressed concrete institute were modeled for the ultra-high performance fiber-reinforced concrete facade panel as illustrations and a finite element method was used to solve the numerical models.

The results of heat transfer analysis showed that steel connections could significantly reduce the thermal resistivity of facade panels by converging heat fluxes and acting as thermal bridges within facade panels. The results also showed that the maximum heat flux in the steel connector of the panel to foundation connection was 10 times higher compared to the other connections. Also, the results of moisture transfer showed that air gaps between the panels had higher moisture flux compared to the other layers in the models. The results show the significant importance of panel connections in the energy performance analysis of facade systems. They also highlight the importance of devising novel connection designs and materials that consider the transient, coupled heat and moisture transfer in the connections to effectively exploit the potential opportunities provided by innovative facade systems to improve building energy efficiency.

This paper, for the first time, investigates the effect of panel connections in the hygrothermal performance of building facade systems using a coupled, transient heat and moisture transfer analysis.

Understanding the dynamic hygrothermal behavior of building elements is very important to ensure the optimal performance of buildings. The Laboratory for Quality Control in Buildings of the Basque Government tested a flat roof designed by a construction company that developed a building to be constructed using prefabricated modules. This is a five to eight floor building with ventilated façade and a flat roof covered by gravel with the possibility of changing it to a green cover. The paper aims to discuss this issue.

The interest of this research was threefold. The first objective was to accurately test, under real dynamic weather conditions, the roof design in a PASLINK test cell to obtain the U-value and the thermal capacitance of the different roof layers, and of the roof as a whole, through the precise calibration of resistance-capacitance mathematical models of the roof. Based on the parameters and experimental information of these calibrated models, a second goal was to calibrate and validate a Wufi model of the roof.

This second calibrated model was then used to simulate the dynamic hygrothermal behavior of the roof, obtaining the roof’s hourly thermal demand per square meter for a whole year in different locations considered in the Spanish Building Code. These simulations also permitted the authors to study the risk of condensation and mold growth of the tested component under different climatic conditions.

The successful combination of the PASLINK method to calibrate the Wufi hygrothermal model is the main novelty of this research.

This study aimed to investigate the collective effects of bending load and hygrothermal aging on glass fibre-reinforced plastics (GFRP) due to the fact that stress and water absorption is inevitable during GFRP applications.

The water boiling method was used to study the moisture absorption, desorption behaviour and evaluate the performance of GFRP laminates under loading in this article. The moisture diffusion of laminates is characterized in three aging conditions (25°C, 45°C and 65°C water), along with three levels of bending load coefficients (0, 0.3 and 0.6). The moisture diffusion coefficients are determined through the curve fitting method of the experimental data of the initial process, based on the Fickian diffusion model. Moreover, the laminates’ performance is further discussed after adequate environmental aging and loading.

It was found that moisture absorption is promoted by the presence of bending load and boiling during this study. The absorption diffusion coefficient and moisture equilibrium content of the specimens increased with an increasing loading ratio and temperature. The bending strength of the laminate varied according to a contrary trend. Furthermore, the desorbed moisture content is found to be much higher after higher levels of bending load because it is harder to desorb the moisture in the interfaces and micro cracks.

Collective effects of bending load and hygrothermal aging promote the absorption and result in accelerating property degradation of GFRP. It is significant to focus on these effects on the failure of GFRP.

A novel unit was designed to simulate the various loading acted on containers in this work.

The surface temperature of the sub-roof beneath the ventilation layer and the tiles is one of the most important factors for the hygrothermal performance of pitched roofs. The air layer between tiles and sub-roof and the air exchange with the outdoor air influence the heat transfer and therefore affect the moisture level inside the roof construction. The paper aims to discuss these issues.

This paper provides the results of a research project performed at Fraunhofer-Institute for Building Physics, based on field test results. The investigations analyze the thermal behavior of different vented and ventilated roof constructions.

It was found that for a detailed model with roof cladding and ventilated air layer normally too many parameters are unknown. For that reason a simplified approach was set up, especially to consider the radiation exchange between the tiles and the underlay as well as the effects of the ventilation.

Now, effective surface transfer parameters can substitute both cladding and air layer in the simulation, while the approach still provides a high accordance with the measured values. The paper provides characteristic values for different roofing situations to simulate ventilated roofs by means of hygrothermal simulation in a simplified way.

The purpose of this paper is to describe how healthy performance of facilities can be monitored and performance data delivered as information flow according to specific user groups' needs.

The context of performance in facilities is described, and a tool for the collection of performance data and communicating the data as relevant information for the facility management (FM) and other stake holders is developed.

Various user groups are utilizing the same performance data to ensure optimal and healthy conditions. The integration of performance data to deliver meaningful and exploitable results for each user requires collection of the relevant data, compilation of data into information, and delivery of user specific information to the correct instance. A performance sensing system with data management was developed into a FM tool for this purpose.

FM is enabled to real time decision making by sensor‐based performance monitoring.

The results are generic and FM tools may be built on this basis for the specific information and display needs of various FM professionals and other stakeholders.

The purpose of this paper is to describe and discuss initial work to assess the moisture buffering performance of selected bio-insulations in lofts that suffer from excessive moisture following refurbishment.

These conditions were then reproduced in a physical lab-based experiment such that the comparative performance of the bio-insulations and stone wool could be measured.

It was found that the bio-insulations could remove over 60 per cent of the moisture in the loft air, and therefore reduce the risk of condensation and its severity.

The initial work reported here is indicative of the buffering potential of bio-insulations but further work is required to better quantify this performance. There is a need to further examine lofts with moisture problems and to produce reliable testing methods and protocols to be used when retrofitting loft insulation.

Installers and specifiers of loft insulation should ensure that insulation is installed correctly, as with the drive to increase loft insulation levels the risks of damaging the building fabric through condensation are increasing.

Excessive moisture can damage the building fabric and create health problems. Using insulations that perform well across a range of performance criteria tend to favour bio-insulations, which have a far less harmful impact on the environment than do typical fossil-fuel based insulations.

The paper presents preliminary findings that support arguments for specifying bio-insulations.

The purpose of this paper is to present a case study of cracks on external thermal insulation composite systems (ETICS) along the thermal insulation joints and the information available on the building pathology catalogue – PATORREB. The aim is to establish the methodology to study the cause of the pathology observed on a building which is located on the interior of Portugal based on in situ probing together with the analysis of hygrothermal and mechanical behaviour.

An in situ analysis was performed to assess the causes. The hygrothermal dynamic behaviour of the wall was analysed with a numerical simulation advanced tool considering the climatic conditions, the characteristics of the thermal insulation plates as well as the support and finishing layer properties. Moreover, a qualitatively analysis of the mechanical behaviour, based on the bonding process, thermal insulation and exterior rendering properties was performed.

It was concluded that the insulation properties – thermal expansion coefficient and stiffness, the thermal expansion coefficient of the exterior rendering, together with adverse climatic conditions were critical for the appearance of cracks along the plate joints, particularly with spot bonding. The expansion and retraction stresses and the restrained movements of the components can result in bending moments, especially when the insulation material has a high stiffness value, which will create the crack on the rendering system.

A combination between a hygrothermal and mechanical analysis of an ETICS pathology concerning the appearance of cracks with a subsequent integration into a building pathology catalogue.

Crawl space ventilation became essential to avoid moisture damage. Historical houses with wood floor and crawl spaces unventilated correctly often face problems of biological degradation. This paper seeks to address these issues.

In this work a case study of the Egas Moniz museum house, in Estarreja, Portugal, with different building pathologies, such as biological degradation and development of micro‐organisms and fungi, is presented. An experimental campaign was carried out with continuous monitoring of the relative humidity and temperature, to validate the real climatic conditions in the crawl spaces. Additionally, the authors analyse the treatment technologies used in the past and the characteristics of the rehabilitation solutions in order to control the hygrothermal behaviour. Simultaneously, numerical simulation was done using the software tool WUFI‐2D to simulate the hygrothermal building behaviour and a sensitivity study of parameters used was done.

The in‐situ experimental results showed that high values of relative humidity imply biological degradation of the wood floor and the numerical and analytical models used showed the same tendency. The numerical results showed the importance of crawl spaces with a good ventilation to avoid mould growth and, also, suggested that controlled mechanical ventilation is preferable to strongly continuous mechanical ventilation in this type of spaces. The experimental study shows that the continuous functioning of a ventilation system may lead to the occurrence of interior condensation, so a hygro‐regulated system is thus essential to control unwanted condensation, with an appropriate functioning criterion.

In accordance with the numerical and experimental results, the authors proceeded to the implementation of a hygro‐regulated system to ventilate the crawl spaces of the Egas Moniz museum house.

This paper presents a new proposed intervention methodology, in crawl spaces, to avoid mould growth, based on an extraction controlled by a hygro‐regulated ventilator.