Moisture Problems Research Articles

Building defect detection: External versus internal thermography

Many buildings suffer from defects in the building envelope, such as missing insulation, thermal bridging, cracks and moisture problems. Thermography is one technology that can help to identify such defects. However, there are different approaches towards assessing the building envelope. Pass-by thermography is an emerging method, which is used to capture single thermal images of external building elevations. Compared with traditional walk-through thermography, it is much quicker and cheaper to perform. Yet it is currently unclear how successful this methodology is at detecting building defects. This paper qualitatively compares pass-by thermography and walk-through thermography. A set of 122 residential dwellings in South West England was inspected using the both methodologies. Results show that substantially more defects were detected using walk-through thermography, with internal inspections yielding the greatest number of detected defects. Significant constraints with walk-past thermography were identified, such as unknown occupancy behaviour, transient climatic conditions, fixed viewing angles and spatial resolution limitations, which were all found to have a greater impact on image results than during walk-through thermography.Although trends in conductivity defects were found from target comparison analysis between similar dwellings, viewing single external elevations under walk-past thermography was found to miss many different defect types, which would have normally been discovered during traditional walk-through thermography.

HYGROTHERMAL PERFORMANCE OF BUILDING ENVELOPES IN THE TROPICS UNDER OPERATIVE CONDITIONS: CONDENSATION AND MOULD GROWTH RISK APPRAISAL

Poor indoor hygrothermal performance increases the risk of indoor moisture problems and deterioration due to mould growth, corrosion and damage to archival materials. Hence, proper control of indoor thermohygric intensity abates indoor moisture and its associated problems. This paper presents the results of envelopes hygrothermal performance assessments in a hot and humid climate building with varying operational profile between adjacent spaces. The case-studied building runs on 24hrs cooling mode in one part against natural and/or mechanical supply-exhaust fan means on the other. In-situ experiments were combined with hygrothermal analytical methods to assess the envelope thermal quality together with the operative conditions against condensation and mould growth risks. The results show that the building is overcooled leading to poor envelope hygrothermal performance with associated condensation and mould growth problems on non-air-conditioned sides of the envelopes.Â

Procedures to Assist Health Care Providers to Determine When Home Assessments for Potential Mold Exposure Are Warranted

Drawing evidence from epidemiology and exposure assessment studies and recommendations from expert practice, we describe a process to guide health care providers helping their patients who present with symptoms that might be associated with living in damp housing. We present the procedures in the form of a guided 2-part interview. The first part has 5 questions that triage the patient toward a more detailed questionnaire that reflects features of housing conditions known to be reliably associated with exposures to mold and dampness contaminants. We chose the questions based on the conditions associated with moisture problems in homes across the United States and Canada. The goal is to facilitate the clinician's effort to help patients reduce exposure to environmental triggers that elicit symptoms to better manage their disease.

Effect of façade impregnation on feasibility of capillary active thermal internal insulation for a historic dormitory – A hygrothermal simulation study

Internal insulation of external walls is known to create moisture performance challenges due to increased moisture levels and condensation risk on the cold side of the insulation. Capillary active/hydrophilic insulations have been introduced to solve these moisture problems, since they are able to transport liquid moisture to the inner surface and enable it to dry. Experience with this insulation type is rare in Denmark. In hygrothermal 1D computer simulations, several more or less capillary active insulation systems (AAC, calcium silicate, IQ-Therm) in various thicknesses (30–150mm) have been tested for their hygrothermal performance. The original construction was a 228mm solid brick masonry wall in a Copenhagen historic dormitory. All simulated systems showed critical relative humidity values above 80% and high risk of mould growth behind the insulation and some also on the interior surface. A moisture safe construction was only achieved when exterior façade impregnation shielding against driving rain was added. The best system showed acceptable relative humidity values both behind the insulation and on the interior surface, a significant increase in minimum temperature on the interior surface, and a reduction of heat loss through the external wall by 85%. The solely application of impregnation also resulted in a moisture safe solution with significant improvements in all parameters and heat loss reduction by 45%. The main conclusion is that capillary active insulation may not be feasible on solid bare masonry walls without additional driving rain protecting especially in case of multi-storey buildings with thin walls in high precipitation areas.

Studies on preparation of Bio-Paints using fungal bio-colors

Purpose – This paper aims to isolate fungal strains producing natural colours, explore their application as colourant in paints and develop cost-effective durable natural paints. Design/methodology/approach – Fungal strains producing natural colours of different shades were isolated. Colourant production was carried out by fermentation method. Natural lime, milk, oil-in-water emulsion paints using natural microbial colours and eco-friendly ingredients were prepared. Bio-paint applications were carried out and evaluated. Findings – Our results indicate that microbes in general and fungi in specific represent dependable source of variety of natural colours, and cost-effective durable natural paints can be prepared with commonly available natural ingredients using scientific information based on history of paints. Research limitations/implications – Natural colours are gaining importance because of their use in health, nutrition, pharmaceutical, textile and environmental applications. Nature is quite rich in several types of colourants. Chemical synthesis of synthetic dyes is complex and not environmental friendly. Microbial dyes manufactured can evade inherent environmental problems of synthetic dyes and offer significant opportunity as a colourant in paints. However, only generally regarded as safe microbial strains are to be considered for colour production. Practical implications – Choosing natural alternatives to protect the health and environment is the need of hour. Fungal colourants are relatively more stable and robust and offer significant opportunity as a colourant in paints. Cost-effective durable natural paints can be prepared using selected stable fungal colourants with commonly available natural ingredients. High diversity of rich and complex natural colourants can be obtained from microorganisms. With the available techniques of fermentation, natural colours can be produced in large quantities of on an economically viable scale and explored for their applications. Social implications – Bio-paints are eco-friendly natural paints, low volatile organic compounds (VOC) paints or organic paints alternate to conventional paints. Most of these natural paints are durable, breathable, prevent moisture problems, contribute to a positive room climate, use safer technology and are less energy-intensive than conventional latex paints to produce. These paints improve indoor air quality and reduce urban smog and offer beneficial characteristics such as low odour, excellent durability and a washable finish. Originality/value – Many of the old art works that still survive today are a tangible proof and evidence of beauty and durability of natural paints. Organic materials used in these paints include natural pigments of mineral, plant and animal origin and other raw biodegradable ingredients. Successful commercialisation of many microbial pigments for food and textile applications is reported in literature. Therefore, present research work aims at developing natural paints using microbial pigments and recipes that have been successfully used by people for years.

Infrared thermography for assessing moisture related phenomena in building components

In this work the potential of infrared thermography (IRT) to assess moisture related phenomenon was tested. Initially, several set-ups and boundary conditions were created to compare IRT with other techniques and to understand the ideal conditions for accurate IRT. Afterwards, IRT was used to assess capillary absorption on a full-scale laboratory model and the drying process of two exterior walls. The main conclusions were that smaller differences are obtained for low reflectance surfaces and during the night, IRT can detect invisible moisture problems and can be used to assess the drying process, although the phenomenon complexity raises some difficulties if a quantitative approach is intended.

Analysis of Thermal – Moisture Problems in Massive Wooden Sandwich Structures

This article focuses on hygrothermal problems in massive wooden sandwich structures. Wood in sandwich structures is already artificially dried before processing, and therefore does not further shrink, as it does in the case of log cabins. Analysed sandwich structure is composed from three layers, and is formed of wooden beam in interior side, thermal insulation and wooden beam in the exterior side. The composition of analysed structure is considered in different thickness with respect to the required heat transfer coefficient. Massive wooden beam on the exterior side causes troubles which exhibits in the reducing capacity of diffusion of water vapor. It is therefore possible that water vapor condenses on the interface of wood and the thermal insulation under certain boundary conditions. Therefore, it is appropriate to place massive wooden beam closest to the interior side. This solution would improve the balance of the diffusion permeability to water vapor permeating from the interior side to the exterior side.

The Growth of Aspergillus Niger on a Wood Based Material with 4 Types of Wall Finishing

Buildings are a vital component in a human’s daily life. It provides shelter from the environment, weather and animals. Mold growth within the building might be caused by the moisture problems which directly act on it such as water leaks or indirect factor such as high humidity levels. This growth causes esthetic problems and deterioration of its wall coatings. Spores from the fungi also cause health problems to humans. The fungus species studied in this research is Aspergillus niger . The material is made of wood and its finishing is thick wallpaper, thin wallpaper, acrylic paint and glycerol based paint. ASTMD5590-00 standard was used to evaluate fungal growth and to determine if non antifungal agent was effective in inhibiting the amount of fungal growth on four types of wall finishing used on wooden walls. This research was conducted without using any antifungal agent. Highest percentage of growth of the fungi was found on acrylic paint, followed by glycerol based paint and thin wallpaper. Thick wall paper shows the least growth of fungi. The maximum growth is visible on day 12 which is more than 60% by all the wall finishing.

Archeological Test Excavations in Areas to be Affected by a Proposed French Drain West of the Granary, Mission San Jose State Site (41BX3), Bexar County, Texas

Limited archeological test excavations were conducted along the west wall of the granary at Mission San Jose State Historic Site (41BX3) in Bexar County, Texas, during July and August, 1979. The investigations were designed to provide information regarding the presence or absence of significant archeological materials in areas to be affected by the construction of a proposed French drain intended to relieve moisture-related structural problems along the west wall of the granary. six 0.5 by 1 meter test pits were excavated; 1,303 artifacts and 1,809 bone and shell fragments were recovered. Seven features were documented; these included a wall and a flagstone floor remnant, 4 pits and a lime filled trench. The wall and floor may represent the remains of a Spanish Colonial blacksmith shop while the pits probably originated during the late 19th Century. The artifacts are primarily trash resulting from nearly 240 years of activity at the mission complex although some items may be relatable to the smithy. Two alternatives for the proposed construction are suggested: 1) abandon plans for a French drain and develop an alternate non-disruptive method for relying moisture problems; or, 2) continue plans for constructing a French drain but precede the modifications with an intensive program of archeological excavations in a broad area along the west wall of the granary.

Assessing the Applicability of Ground-Penetrating Radar to Quality Control in Tunneling Construction

Ground-penetrating radar (GPR) has proved to be a valuable method for tunneling quality management and evaluation. The research literature includes many successful works addressing the use of this technique with the aim to detect the existence of internal pathologies and anomalies. However, most of them have been carried out on tunnels in operation. In these situations, the identification of inner elements and possible damage has been severely limited due to a shallower rebar mesh that complicates the radar data interpretation process. Therefore, this paper presents the evaluation of an excavated high-speed railway tunnel during the early stages of construction instead of considering a finished one. The purpose of the study was to demonstrate the potential of this method when applied during these first critical phases. The results provided noteworthy information: namely, thickness of the gunite layer, lining voids and delamination, moisture problems, and the presence of reinforcing in the tunnel lining. All this information may be useful for civil engineers when they must make a decision on maintenance and prevention tasks.

Conservation Climate Analysis of a Church Containing Valuable Artworks

The OLV Hemelvaart church in Watervliet dates back from the 16th century and contains valuable panel paintings and wooden artefacts. They need to be preserved in a stable conservation climate. However, due to the old air heating system, the indoor climate is not stable at all. The air heating system creates sudden strong rises in temperature and due to the position of the supply and extraction grilles, the warm air is not evenly distributed throughout the church. Furthermore, the church suffers from moisture problems such as rain penetration and rising damp. In view of improvement measures to the heating system, from March 2012 to March 2014, the temperature and relative humidity was measured on different locations in the church. The ASHRAE conservation classes were used to analyze the data. Both a frequency analysis and an analysis of the short term and seasonal fluctuations of temperature and relative humidity were performed.It was found that the relative humidity of the indoor air was far too high for conservation purposes: during more than 50% of the time a value above 75% was registered in the middle of the church. During a period of two months, the church was permanently heated in order to improve the conservation climate. Compared to the intermittent heating regime, permanent heating caused a more stable climate: the relative humidity level exceeded 75% during 20% of the time, but it remained almost constantly between 60% and 75%. This was attributed to the church walls that acted as a constant moisture source during heating.

Retrofit with Interior Insulation on Solid Masonry Walls in Cool Temperate Climates – An Evaluation of the influence of Interior Insulation Materials on Moisture Condition in the Building Envelope

For historic buildings, where an alteration of the exterior façade is not wanted, interior insulation can be the solution to improve the indoor climate and reduce heat loss, but might also introduce moisture problems like condensation in the wall. Capillary active/hydrophilic insulation materials have been introduced to cope with the moisture problem. An extensive amount of calculations indicating where the challenges lie in the complex work with interior insulation in cool temperate climate has been carried out. In areas with high precipitation like Denmark, capillary active insulation may not be feasible without additional driving rain protecting of the façade.

Design of the Ventilated Air Channel to Resolve Moisture Problems in the Historical Church

The purpose of the research is to find adequate solution against rising damp in historical buildings. The improvement of this case is with ventilated air channel. Special part of historical buildings are churches because not use routinely as for example museums, galleries. We are designed 10 differently construction of ventilated air channel. These are: open or closed, with overpressure and underpressure. We use for verification relevance these construction we simulated in software Ansys CFX the air flow of channels. We modeling the equal segment of the channels. This research should be offer for architects the solution against problems of rising damp for historical buildings. For find the right solution is necessary to research everyone case. The aim of the research is to prepare the design process of the ventilated air channels for the architects without simulation every building, cross section or geometry of these construction.

Environmental Stewardship and Technical Efficiency in Canadian Prairie Canola Production

This study examines beneficial management practice (BMP) adoption and technical efficiency for canola producers in the Canadian Prairie Provinces. A Just‐Pope stochastic frontier production function is estimated using data from a survey of canola producers. Yield is modeled as a function of nutrients and precipitation. A linear inefficiency function includes farm specific variables and a set of binary variables representing BMP adoption. BMP variables for nutrient management planning and precision farming are positively related to technical efficiency while results for the other BMP indicators are mixed. Model estimates appear to be significantly influenced by moisture problems that occurred through the Prairie region during the 2011 cropping year. The study results suggest that for Western Canadian canola producers, there is potential complementarity for some BMPs in terms of improving technical efficiency while simultaneously advancing environmental stewardship.

APPRAISAL OF MOISTURE PROBLEM OF INHERITANCE BUILDING ENVELOPE ASSEMBLIES VIA VISIBLE AND INFRARED THERMOGRAPHY METHODS

In order to gauge the moisture performance of walls and roofs there is a need to investigate the paths of moisture penetrating into the wall assembly, how long and where the moisture stays, and whether it causes temporary reduction of performance or permanent damage. The non-contact safe nature and usefulness in temperature measurement of infrared thermography have made it a popular instrument for building diagnostics. Hence, this paper depicts a documentation process which makes use of both visible and infrared thermal images to identify moisture anomalies in heritage building envelope assemblies. In sequence to achieve the purpose, visible and infrared thermal images are recorded for comparison and further analysis. It can be concluded that infrared thermal imaging camera is useful for identification of moisture problems in building façade, whereas combination of both visible and infrared thermal imaging methods produces a more advanced, accurate and effective approach for building diagnostics.

The Utilization of Waste Aluminosilicate to Prepare Cement Composite with Thermal Insulating and Drying Effect

Increasing energy prices, along with escalating demands for thermal insulation properties of enclosure structures, force the owners of buildings to reduce the operating costs of heating. That is why the question of reducing the energy consumption of buildings, also including the category of historical buildings [10], has been gaining ground. The reduction of energy consumption of these buildings is often accompanied by the requirement to eliminate moisture problems of base structures caused by leaking or broken waterproofing of the bottom part of the object. The subsequent increase of the thermal resistance of the building envelope must be performed by means of special insulation materials allowing the drainage of liquid water from the structure. The paper presents the properties and the influence of the developed materials on the course of built-in moisture in the base structure affected by this phenomenon using Delphin simulation software, based on the measured thermal and technical parameters. The developed material is a composition of pozzolan binder, foaming agent and waste resulting from the production of cellular concrete blocks. According to tests carried out in [1], it is possible to produce concretes with sufficient strengths for rehabilitation boards when you substitute natural aggregates with waste aluminosilicate and, according to [2, 3, 4, 5, 6], you will achieve better rehabilitation and thermal insulation properties by using porous filler. The developed material is intended for the so-called soft rehabilitation, and its function is specifically presented on a structure built from sandstone blocks. This type of structures can be found in north Bohemia and the application of rehabilitation work must be very carefully considered, because quick drying of built-in moisture in masonry, for instance by means of cutting the lower part of the structure and by inserting waterproofing, will cause shape changes of the structure accompanied by the formation of cracks.

Evaluation of different water flow rates of nipple drinkers on broiler productivity

Watering systems utilized in broiler production can impact bird performance. Many companies have increased water flow rates (WFR) in their nipple drinkers (ND) system during brooding above the manufacturers recommended level, then make adjustments in WFR during the grow period. This has increased moisture and early caking problems in litter. The objective of this study was to determine how birds perform on different WFR rates during brood and grow periods while observing litter condition. Seven WFR treatments were evaluated for broilers reared from 1 to 42 d age: 50 mL/min, 75 mL/min, 100 mL/min, 120 mL/min, 50 mL/min 1 to 7 d increasing to 75 mL/min 8 to 42 d, 75 mL/min 1 to 7 d increasing to 100 mL/min 8 to 42 d, and 100 mL/min 1 to 7 d increasing to 120 mL/min 8 to 42 d. Chicks were identified and randomly allocated in a randomized complete block design. BW, cumulative feed consumption (FC), FCR (feed:BW), litter moisture (%), and litter moisture under the ND were determined weekly to 42 d. Mortality (MO) was recorded daily. Birds tended to have heavier BW on d 35 when (P = 0.08) on the higher WFR (75, 100, and 120 mL/min) in comparison to birds on the lowest WFR (50 mL/min). No differences were observed for FC, FCR, or MO. Birds on treatments with higher WFR (100 and 120 mL/min) and treatments which were increased to higher WFR (75 to 100 mL/min and 100 to 120 mL/min) utilized greater amounts of water as compared to birds receiving lower WFR (50 and 75 mL/min). The 100 and 120 mL/min WFR resulted in higher percent litter moisture (P ≤ 0.01) under the ND but decreased at the end of the growing period. In conclusion, as birds become heavier, they attempt to utilize larger amounts of water from ND with greater WFR without any beneficial effect on bird performance. As WFR increase, litter moisture under the ND will initially increase but then decrease as the birds age.

Indoor air quality in passive and conventional new houses in Sweden

The indoor environment was evaluated in 20 new passive houses and 21 new conventionally built houses during the 2012/2013 and 2013/2014 heating seasons. Temperature, relative humidity (RH), the concentrations of NO2, ozone, formaldehyde, volatile organic compounds (VOC) and viable microbiological flora were measured. Air exchange rates (AER) were estimated from the CO2 concentrations measured in the bedrooms. The median AER was slightly higher in the passive houses than in the conventional ones (0.68 h−1 vs. 0.60 h−1). The median concentrations in the passive and the conventional buildings were 10 and 12 μg/m3 for NO2, 9.7 and 11 μg/m3 for ozone, 11 and 16 μg/m3 for formaldehyde, and 270 and 150 μg/m3 for TVOC, respectively. Significant differences in the TVOC and formaldehyde concentrations between the two groups of buildings indicated substantial sources of TVOC present in the passive houses, while sources of formaldehyde may have been more pronounced in the conventional houses. In contrast to the passive houses, the indoor microbiological flora indicated possible mould or moisture problems in six (29%) of the conventionally built houses. When compared with the results previously reported for the Swedish housing stock, AERs and NO2 concentrations were significantly higher in both groups of newly built buildings, while formaldehyde concentrations were significantly lower in the passive houses. TVOC concentrations were not significantly different from those reported for the housing stock, although the most abundant individual VOCs were present mostly at higher concentrations in the new buildings.

A Case Study on Moisture Problems and Building Defects

Hospital buildings are one of the complicated buildings that normally associate with a moisture problem. Besides environment factor, the different operation hour, poor workmanship and improper waterproofing installation also contributes to the moisture problems. Controlling the moisture problems seem to be vital in ensuring the building functionality. This study identifies the moisture problems and it's causes for the Hospital buildings in Malaysia. Based on various records obtained, this study discusses the defects according to four major building elements that are ceiling, wall, floor and roof. This paper concludes that the identified defects have great potential to affect the hospital building function.

A systemic approach to moisture problems in buildings for mould safety modelling

Mould growth in buildings can have negative consequences on health, comfort, and durability of construction and can cause a significant problem for inhabitants. Confronted with significant uncertainty, deterministic tools supporting design have proved insufficient for decision making. A tool that addresses the probabilistic risk/reliability analysis of building performance is needed. A systemic approach provides a proper theoretical base for the analysis. Based on a qualitative fault tree analysis, structure related vulnerabilities to moisture problems have been classified at different levels of the building construction: whole structure, component or material. A general model for evaluating the reliability of structures with respect to mould safety and based on the concept of systemic analysis is applied to moisture problems in buildings using a probabilistic limit state approach.An example of a risk analysis of mould germination on the inner surface of a wooden roof panel in a cold attic is calculated using the proposed methodology. The surface's relative humidity (given certain surface temperature interval) is chosen as a performance aspect. The performance criteria for mould germination on wood are also treated as a random variables. The probability of mould germination is evaluated for different attic floor constructions in which changes to the construction were introduced on the material or component level. The application of the probabilistic model of mould germination makes comparisons of alternative cold attic constructions possible. Uncertainties coupled to the proposed methodology are discussed.