Damp Buildings Research Articles

Stachybotrys chartarum: cause of human disease or media darling?

This is a review of the literature of associations of the saprotrophic fungus Stachybotrys chartarum sensu lato with human and animal illnesses. This fungus grows on very wet cellulose-based building materials. S. chartarum has been the subject of considerable media attention because of temporal associations of exposure with unexpected and dramatic outcomes such as infant pulmonary hemosiderosis and neurocognitive damage. It is generally accepted that living or working in mouldy environments is associated with building related asthma, exacerbating asthma in mould-sensitive asthmatics and increased rates of upper respiratory disease. However, such relationships are with building-associated moulds, comprising many species that colonize wet or damp building materials, and are not specific to S. chartarum. There is limited evidence that severe lung damage can occur from building exposure to S. chartarum but possibly only under conditions of exposure that approach those associated with handling contaminated straw. There is no positive evidence in the literature to account for putative neurological damage resulting from exposure to this mould.

Ocular, airway, and dermal symptoms related to building dampness and odors in dwellings.

The authors examined the relationship between symptoms of Sick Building Syndrome and reports of building dampness and odors. Two hundred thirty-one multifamily buildings built prior to 1961 in Stockholm, Sweden, contained a total of 4,815 dwellings. The authors selected these buildings for study by stratified random sampling. Occupants answered a postal questionnaire that assessed weekly symptoms, personal factors, population density in each apartment, water leakage in the preceding 5 yr, different types of odors, and signs of high indoor air humidity. The response rate was 77%. Independent information on building characteristics was gathered from the building owners and the central building register in Stockholm. Multiple logistic-regression analysis was applied and odds ratios were calculated, with adjustments for age, gender, current smoking, hay fever, population density, type of ventilation, and ownership of the building. In total, 22% reported at least 1 sign of dampness, and 32% reported odor in the dwelling. Condensation on windows, high air humidity in the bathroom, moldy odor, and water leakage were reported from 6.8%, 8.8%, 5.7%, and 13% of the dwellings, respectively. A combination of odor and signs of high humidity was related to an increased occurrence of all symptoms (odds ratios = 2.2-3.6). Similar findings were observed for a combination of odors and a history of water leakage in the past 5 yr (odds ratios = 1.2-4.4). Symptoms increased with the number of signs of dampness. The study indicated that dampness in dwellings, with emissions of odorous compounds, are associated with an increase in symptoms consistent with Sick Building Syndrome.

Higher-mode effect on the seismic responses of buildings with viscoelastic dampers

In conventional modal analysis procedures, usually only a few dominant modes are required to describe the dynamic behavior of multi-degrees-of-freedom buildings. The number of modes needed in the dynamic analysis depends on the higher-mode contribution to the structural response, which is called the higher-mode effect. The modal analysis approach, however, may not be directly applied to the dynamic analysis of viscoelastically damped buildings. This is because the dynamic properties of the viscoelastic dampers depend on their vibration frequency. Therefore, the structural stiffness and damping contributed from those dampers would be different for each mode. In this study, the higher-mode effect is referred to as the response difference induced by the frequency-dependent property of viscoelastic dampers at higher modes. Modal analysis procedures for buildings with viscoelastic dampers distributed proportionally and non-proportionally to the stiffness of the buildings are developed to consider the higher-mode effect. Numerical studies on shear-type viscoelastically damped building models are conducted to examine the accuracy of the proposed procedures and to investigate the significance of the higher-mode effect on their seismic response. Two damper models are used to estimate the peak damper forces in the proposed procedures. Study results reveal that the higher-mode effect is significant for long-period viscoelastically damped buildings. The higher-mode effect on base shear is less significant than on story acceleration response. Maximum difference of the seismic response usually occurs at the top story. Also, the higher-mode effect may not be reduced by decreasing the damping ratio provided by the viscoelastic dampers. For practical application, it is realized that the linear viscous damping model without considering the higher-mode effect may predict larger damper forces and hence, is on the conservative side.

Volatile metabolites from microorganisms grown on humid building materials and synthetic media.

Growth of different microorganisms is often related to dampness in buildings. Both fungi and bacteria produce complicated mixtures of volatile organic compounds that include hydrocarbons, alcohols, ketones, sulfur- and nitrogen-containing compounds etc. Microbially produced substances are one possible explanation of odour problems and negative health effects in buildings affected by microbial growth. A mixture of five fungi, Aspergillus versicolor, Fusarium culmorum, Penicillium chrysogenum, Ulocladium botrytis and Wallemia sebi were grown on three different humid building materials (pinewood, particle board and gypsum board) and on one synthetic medium. Six different sampling methods were used, to be able to collect both non-reactive volatile organic compounds and reactive compounds such as volatile amines, aldehydes and carboxylic acids. Analysis was performed using gas chromatography, high-performance liquid chromatography and ion chromatography, mass spectrometry was used for identification of compounds. The main microbially produced metabolites found on pinewood were ketones (e.g. 2-heptanone) and alcohols (e.g. 2-methyl-1-propanol). Some of these compounds were also found on particle board, gypsum board and the synthetic medium, but there were more differences than similarities between the materials. For example, dimethoxymethane and 1,3,5-trioxepane and some nitrogen containing compounds were found only on particle board. The metabolite production on gypsum board was very low, although some terpenes (e.g. 3-carene) could be identified as fungal metabolites. On all materials, except gypsum board, the emission of aldehydes decreased during microbial growth. No low molecular weight carboxylic acids were identified.

Chemistry and toxicology of molds isolated from water-damaged buildings.

There is increasing evidence of health risks associated with damp buildings and homes in which high levels of microbes are found. Although concerns have traditionally centered on microbial pathogens and allergenic effects, recent work has suggested that fungi pose the more serious risk. Evidence is accumulating that certain toxigenic molds are particularly a risk for human health through exposure, via inhalation, of fungal spores. Many of these fungi produce toxins (mycotoxins) some of which have been shown to cause animal and human intoxications, usually in an agricultural setting. The fungus, Stachybotrys chartarum (S. atra) is considered to be one of the more serious threats to people living and working in water-damaged buildings. This mold has a long history of being responsible for animal toxicoses, and in recent years, being associated with infant pulmonary hemosiderosis (bleeding in the lungs) of infants exposed to spores of this fungus in their homes. S. atra produces a variety of potent toxins and immunosuppressant agents, including a novel class of diterpenes (atranones) of unusual structure. More research is needed to determine the impact to health resulting from inhalation of toxigenic mold spores.

Sick building syndrome in relation to building dampness in multi-family residential buildings in Stockholm. Engvall, K., Norrby, C., and Norback, D.: Int. Arch. Occup. Environ. Health, 74(4): 270-278, 2001.(Abstracts of foreign literature)

Sick building syndrome in relation to building dampness in multi-family residential buildings in Stockholm. Engvall, K., Norrby, C., and Norback, D.: Int. Arch. Occup. Environ. Health, 74(4): 270-278, 2001.(Abstracts of foreign literature)

Damping measurements of steel poles and tubular towers

The evaluation of the wind-induced response of light and slender structures is strictly bound to damping modeling. While several papers exist dealing with damping of buildings, forecasting models concerning steel poles and tubular towers are almost totally lacking. In order to properly appreciate this quantity, an experimental full-scale activity has been undertaken whose aim, execution and results are herein described. At present, four structures have been investigated providing, for each of them, the logarithmic damping decrement as a function of motion amplitude. Results illustrated by this paper are part of a wider research aimed at formulating suitable damping models and analyzing the role of this parameter in the wind-excited response of structures.

Dampness in buildings and health. Nordic interdisciplinary review of the scientific evidence on associations between exposure to "dampness" in buildings and health effects (NORDDAMP).

Several epidemiological investigations concerning indoor environments have indicated that "dampness" in buildings is associated to health effects such as respiratory symptoms, asthma and allergy. The aim of the present interdisciplinary review is to evaluate this association as shown in the epidemiological literature. A literature search identified 590 peer-reviewed articles of which 61 have been the foundation for this review. The review shows that "dampness" in buildings appears to increase the risk for health effects in the airways, such as cough, wheeze and asthma. Relative risks are in the range of OR 1.4-2.2. There also seems to be an association between "dampness" and other symptoms such as tiredness, headache and airways infections. It is concluded that the evidence for a causal association between "dampness" and health effects is strong. However, the mechanisms are unknown. Several definitions of dampness have been used in the studies, but all seems to be associated with health problems. Sensitisation to mites may be one but obviously not the only mechanism. Even if the mechanisms are unknown, there is sufficient evidence to take preventive measures against dampness in buildings.

Serum IgE specific to indoor moulds, measured by basophil histamine release, is associated with building-related symptoms in damp buildings.

To study the relationship between basophil histamine release (HRT) to indoor moulds, indicating specific IgE, and building-related symptoms (BRS), asthma, and hay fever in individuals working in damp and mouldy buildings. A cross-sectional study was performed among 86 school staff members, who on average had worked 143 months (range: 3-396) in moist buildings with mould growth in the constructions. A questionnaire concerning mucous membrane symptoms, facial skin symptoms, central nervous system symptoms, hay fever, and asthma was fulfilled by the participants, and blood samples were taken. Eight mould species growing on building constructions were identified and cultivated to obtain allergenic materials for testing. The presence in serum of IgE specific to moulds was verified by histamine release test (HRT) based on passive sensitization of basophil leukocytes. The validity of the method was confirmed by parallel testing of patients allergic to grass- and birch pollen and by the shift from positive to negative response after removal of serum IgE and by using sham sensitization. The prevalence of most BRS was between 32% and 62%. Positive HRT, showing serum IgE specific to one or more of the moulds, was observed in 37% of the individuals. The highest frequency of positive HRT was found to Penicillium chrysogenum and then to Aspergillus species, Cladosporium sphaerospermum and Stachybotrys chartarum. A significant association was found between most BRS and positive HRT, whereas no association was observed between positive HRT to moulds and self reported hay fever or asthma. Positive HRT to indoor moulds, showing the presence in serum of IgE specific to the fungi, was found to be related to BRS in individuals working in damp and mouldy buildings. Whether the association is of causal character is a question for further studies. The test may be useful in the evaluation and study of possible mould induced BRS.

Nasal hyperreactivity among teachers in a school with a long history of moisture problems.

Upper airway symptoms have frequently been reported in people working or residing in damp buildings. However, little information has been available on objective pathophysiologic findings in relation to these environments. Twenty-eight teachers, who had worked for at least five years in a recently renovated school that had had severe moisture problems for years, were randomly selected for this study. Eighteen teachers, who had worked in another school that had no moisture problems, were randomly selected to serve as the control group. Although remedial measures had been taken, an increase in the prevalence of mucous membrane irritations was still reported by the teachers in the target school. We used a nasal challenge test with three concentrations of histamine (1, 2 and 4 mg/mL). Recordings of swelling of the nasal mucosa were made with rhinostereometry, a very accurate optical non-invasive method. The growth curves of mucosal swelling induced by the three concentrations of histamine differed significantly between the two groups (p < 0.01). The frequencies of atopy, evaluated with the skin-prick test, were almost identical in both groups. The study indicates that long-term exposure to indoor environments with moisture problems may contribute to mucosal hyperreactivity, of the upper airways. Such hyperreactivity also seems to persist for at least one year after remedial measures have been taken.

Nasal lavage biomarkers: effects of water damage and microbial growth in an office building.

Selected nasal symptoms were studied in personnel who worked in a damp office building that had microbial growth (including Stachybotrys sp.) in mineral fiber insulation and gypsum board. There were also signs of dampness in the floor. Clinical examinations included nasal lavage and peak expiratory flow measurements in 12 subjects in the damp building; an additional 8 subjects in a control building (i.e., no signs of dampness or microbial growth) were also examined. Hygienic air measurements of microorganisms and volatile organic compounds were performed in both buildings. The concentrations of eosinophil cationic protein, myeloperoxidase, and albumin, and the number of subjects with eosinophils in lavage fluid, were higher among office workers in the damp building than among controls. The damp biiilding had greater amounts of total molds and bacteria in its construction than the building materials in nondamp buildings. In addition, an increase of 2-ethyl-1-hexanol in the indoor air was detected in the damp building-a sign of dampness-related alkaline degradation of diethyl-hexyl phthalate in polyvinyl chloride floor coatings. In conclusion, the results of this study indicate that exposures in a damp office building may cause an inflammatory nasal mucosal response. The results also support conclusions of earlier studies, indicating that building dampness is related to respiratory inflammation.

Induction of Cytotoxicity and Production of Inflammatory Mediators in RAW264.7 Macrophages by Spores Grown on Six Different Plasterboards

Dampness and microbial growth in buildings are associated with respiratory symptoms in the occupants, but details of the phenomenon are not sufficiently understood. The current study examined the effects of growth conditions provided by six plasterboards on cytotoxicity and inflammatory potential of the spores of Streptomyces californicus, Penicillium spinulosum, Aspergillus versicolor, and Stachybotrys chartarum. The microbes were isolated from mold problem buildings and thereafter grown on six different plasterboards. The spores were harvested, applied to RAW264.7 macrophages (104, 105, 106 spores/106

Conservation Strategies for Damp Buildings and Plaster: Lacock Abbey in Wiltshire

The transformation of the thirteenth-century nunnery of Lacock into a country residence at the time of the Dissolution has resulted in a complex structure, now with serious damp problems affecting the historic fabric. As owner of the Abbey, The National Trust has initiated an integrated conservation strategy to address the causes of decay. Surveys were undertaken to confirm the principal source of moisture and its distribution, and the types of soluble salts and microbiology present. A fuller understanding of the building has been afforded by monitoring the environment, groundwater variations and thermal transmission, and undertaking in situ quantification of microbiological growth through ultraviolet and infrared photography, and induced fluorescence, before and after irradiation with ultraviolet light. Urgent remedial conservation of fragile medieval wall plaster and limewashes has been carried out using lime-based techniques, with a cellulose ether (Tylose) as an adhesive and a silica colloid (Syton) as a plaster consolidant for limited areas. Future work will entail comprehensive assessment of site drainage and necessary improvements.

Form Follows Structure: Law, Regulation and Design for Buildings that Preserve Human Health

Each architect's ability to translate complex notions of function into two-dimensional drawings into solid form is remarkably powerful, and it is a unique attribute of human minds. The architect's professional power can be used to design buildings that will foster better human health, or that can needlessly harm the inhabitants, depending on whether sufficient attention has been given to health and safety issues. As this conference itself has noted in its statement of purpose, There is growing concern about the health effects of biological contaminants in indoor air due to damp and moisture problems of The purpose of this follow-up meeting is to provide a forum for the discussion of new research findings and to provide professionals in this field with concise information and expert opinions. It is also an exceptional opportunity to learn of future trends in scientific research. The expert Conference in Saratoga Springs in 1998 discussed in detail many aspects of exposure assessment, clinical findings, cellular mechanisms of the health effects, case studies and prevention, mitigation and control of microbial problems associated with excess dampness and moisture in buildings. Laws and regulations, the rule of law as well as the laws of nature, control how buildings look, what functions they are allowed to serve and whether they will meet standards for inspection, occupancy and use that conform to the requirements in practice as well as under law. Yet, the shape and structure of buildings reflects human values that can either promote or hinder human health. As noted in the landmark report, BUILDING COMMUNITY, education is really about fostering the learning habits needed for the discovery, integration, application and sharing of knowledge over a lifetime...however, what this also points up is the architecture community's long history of failure to connect itself firmly to the larger concerns confronting families, businesses, schools, communities and society. In the area of indoor air quality, the controversy regarding the origins and impacts of so-called Sick and the political movement that has sprung up calling for Buildings, these views of the political shortsightedness of architects and their profession has proven to be prophetic. Yet, an architect's ability to translate complex notions of function into two-dimensional drawings, then into solid form is an untapped resource for tackling the problems of sick Architectural design is one of several tools; sometimes competing tools -- that can be used as an analytical system for problem-solving around human-created environments and the positive or negative impacts of those constructed structures upon human health. Scientific research regarding the health, potential health hazards, or safety and security of certain structures has yet to consider the profound implications of form, structure and uses of architectural design for various uses of Yet, there are instances where an architect's intervention can reduce exposure to mold or alter the airflow that breeds a vector for disease. The bringing together of architects, scientists and the lawyers who create housing codes, inspection criteria and other types of regulation could ultimately result in an unprecedented benefit whereby unhealthful building uses have been transformed through thoughtful design to improve their inhabitant's health, thus providing a better quality of life and significant cost savings from illness, at the same time. But such a grand and urgently needed meeting of the minds has yet to occur. The questions to be addressed when designing, constructing, regulating or using Health Buildings must be considered from the standpoint of at least three discisiplines: 1) scientific (with its myriad subdivisions and subspecialties); 2) law and regulation to prevent harms, remedy harms or improve conditions; and 3) architectural design that can modify actual conditions or design Healthy Buildings. Like three sides of a triangle, these disciplines, their perspective or angles on the specific problems raised by the need for healthy buildings are both distinct and interdependent. No structure can truly survive without considering the whole; missing one part, the structure falls away. So too, since buildings are actually three dimensional, it is possible that there are other disciplines that should be included in this discourse, that to be truly successful in the tasks of analyzing these problems, if we wish to make positive changes in the existing situations or the slow down the existing trajectory of potential harm, there must be a way to create a model for problem-solving discourse that is multi-dimensional, embracing more disciplines. Under the present situation, however, this concept of legal aspects and scientific concerns and architectural design would be addressed by three or four different conferences each in their respective professions. It is time, instead to cross-fertilize information by bringing in the considerations from other disciplines.

Volatile metabolites from mold growth on building materials and synthetic media

Mold species which were isolated from damp buildings were grown on sterile building materials and some synthetic media in order to study the microbial volatile organic compounds produced. Patterns of the microbial volatile organic compounds (MVOC) were very media dependent but media which favor terpene biosynthesis may give patterns unique enough for identification of dominant indoor molds.

A breeding ground for potent asthma triggers

The use of volatile organic compounds (VOCs) to detect mold growth in damp buildings depends on a comprehensive knowledge of the biosynthetic pathways available to indoor molds as well as their biological variation. Recent reports concerning (VOCs) formed during the growth of molds from damp buildings on laboratory substrates indicate considerable variation, presumably because of the sensitivity of mold VOC biosynthesis to environmental conditions or large biological variation.

Mold-Specific Immunoglobulin E Antibodies in Primary School Students: A 3-Year Follow-Up Study

The relationship between dampness and mold growth in buildings and respiratory health problems of inhabitants has been observed in many epidemiologic studies. The purpose of the present study was to evaluate the occurrence of mold allergy at school age with special attention paid to mold-specific immunoglobulin E (IgE) in relation to asthma, skin prick test (SPT) results, and exposure in the school in a follow-up study design. In 1996, 212 primary school students with asthma, wheezing, or prolonged cough participated in a clinical study, including SPTs to 12 molds in all and serum mold-specific IgE determinations to 10 molds in selected cases. Three years later, 144 of them participated in an identical follow-up study, the serum mold-specific IgE was measured in the 17 children who reacted to molds in SPTs and in 45 age- and sex- matched SPT-negative controls from the same schools. Seven (11%) of the 62 students had elevated mold-specific IgE. In addition, there were uncertain results in 3 cases. An elevated or uncertain IgE concentration was found in 4 (67%) of the 6 children with positive SPT, in 3 (27%) of the 11 children with weakly positive SPT, and in 3 (7%) of the 45 children with no SPT reactions to molds. The presence of IgE was associated with clinical atopy and SPT reactivity to common allergens. However, no association with moisture or mold problems in the school was seen. Serum mold specific IgE was rarely positive at school age. A rather good agreement was seen between mold-specific IgE and SPTs to molds. Mold-specific IgE was positive mostly in atopic children with no association with exposure in the school. (Pediatr Asthma Allergy Immunol 2000;14(2):101–108.)

Frost Damage of Masonry Walls A Hygrothermal Analysis by Computer Simulations

INTRODUCTION AND OBJECTIVES Frost damage occurs especially if damp building elements are subjected to frequent freezethaw cycles. The observation that frost damage can also be frequently observed in warmer winters – for example in the winter of 98/99 (see Figure 1) confirms that one cannot use the outside air temperature level as the only criterion, but that the combination of the number of freeze-thaw cycles in the building element’s interior and the moisture content in the material at those times must also be considered. The number of zero crossings on a Celsius scale during each half year of the winter, and the corresponding moisture content profiles were calculated using the PC program WUFI [1] for the example of a calcium silica brick (csb) wall construction. The effect of different meteorological conditions on zero crossings and material moisture has been determined using meteorological data measured during several years at the Fraunhofer-Institute for Building Physics (IBP) outdoor testing field. From the results, it is possible to assess the frost damage risk.

The National Preservation Office: Raising Preservation Awareness in the UK Now – Planning for the Future of Our Past

The National Preservation Office in the UK was established within the British Library in 1984, guided by independent advisory machinery. A vigorous programme of seminars, conferences, training packs and promotional material, including a journal, has been carried out. The NPO's terms of reference are to develop and coordinate a national preservation strategy, provide an information and referral service, promote good practice through education and training, and coordinate and initiate research. Commercial sponsors have been generous. There is a Management Committee, drawn from the principal funders, a Preservation Administrators Panel to advise on preservation strategy, a Committee on Preservation Surrogates, and a Digital Archiving Working Group. Several research projects are being supported, including work on gaps in preservation training, resolving dampness in buildings, and preservation management of digital materials. This last is now occupying a great deal of attention, and the NPO works closely with other preservation initiatives in the UK and abroad. Much work is also taking place towards a national preservation strategy.

Nasal and ocular symptoms, tear film stability and biomarkers in nasal lavage, in relation to building-dampness and building design in hospitals

To study the relationships between dampness in concrete floors and building design on the one hand, and symptoms and medical signs of the eyes and nose in hospital workers, on the other. Four hospitals for geriatrics were selected to represent buildings with different ages and design, irrespective of symptom prevalence. The first building was built in 1925. The second, built in 1985, was known to have dampness in the floor. Conventional building techniques were used in the third building, built in 1993, and the last building was built in 1994, and was specially designed to include high ceilings, and minimal use of fluorescent lighting and interior plastic materials. The interior surfaces were painted with water-based beeswax glazing. All staff (n=95) working day shifts were invited to take part in a medical examination of the eyes and nose including acoustic rhinometry and nasal lavage, and a medical questionnaire, and 93% participated. Measurements of temperature, relative air humidity, air flow, illumination, volatile organic compounds (VOCs), molds, and bacteria were carried out in all buildings, together with measurements of formaldehyde, respirable dust, carbon monoxide (CO), carbon dioxide (CO(2)), nitrogen dioxide (NO(2)) and ozone. Statistical analyses were performed by bivariate analysis, and linear, ordinal, and logistic multiple regressions, adjusting for age, gender, tobacco smoking, atopy, and the perceived psychosocial work environment. Dampness in the upper concrete floor surface (75-84%), ammonia under the floor [3 parts per million (ppm)], and 2-ethyl-1-hexanol in the air were detected in the two buildings built in 1985 and 1993. Increased occurrences of ocular and nasal symptoms, an increased concentration of lysozyme in nasal lavage, and decreased tear film stability were found in the subjects working in the damp buildings. Those in the specially designed building had fewer ocular and nasal symptoms, and increased tear film stability. All buildings had low levels of formaldehyde, molds, bacteria, ozone, and NO(2). The lowest total concentration of VOCs, and the highest concentration of specific VOCs of microbial origin, were found in the building with special design. The study provides new evidence of the role of dampness-related alkaline degradation of di-(2-ethylhexyl) phthalate (DEHP) in polyvinyl chloride (PVC) building material. Emissions related to degradation of DEHP due to dampness in the floor, indicated by increased 2-ethyl-1-hexanol in the air, seem to increase both the secretion of lysozyme from the nasal mucosa and the occurrence of ocular and nasal symptoms. The indoor environment of the specially designed building with high ceilings and no fluorescent lighting or interior plastics seemed to have a positive influence on the nasal and ocular mucous membranes.