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Results on termite resistance of building materials against Coptotermes formosanus by choice test
1998 - IRG/WP 98-10275
Various building materials, included wood species, wooden board materials, thermal insulation materials and fire-protection materials, were tested for grading of termite resistance against Coptotermes formosanus. The dimension of most specimens were 2x2x2cm3. Ten repeats were prepared. The specimens were put between Akamatsu sapwood control specimens on a laboratory cultured mound colony of termite, Coptotermes formosanus. After 1 month of attack to termite, the specimens were removed from the mound colony and cleaned up. Then these final mass were weighed. The grading of termite resistance was initially estimated by mass loss of specimens. This grading was corrected by visual observation. Japanese 3 domestic species, cypress pine, Alaska- ceder, kapur and mahogany were indicated rather high termite resistance. In the case of Siberian red pine and Gmelina, the valued of termite resistance were shown variable. Tropical species plywood, inorganic board and radiata pine MDF, were shown rather high termite resistance. Other board materials were shown rather less termite resistance. Most of commercial soft wood plywood and OSB were very sensible against termite. Most common thermal insulation materials in Japan were estimated very sensitive against termite. In the case of fire protection materials, expanded concrete was rather good against termite but plaster board was very sensible against termite.
K Suzuki, K Hagio

Work program of CEN/TC 38 (April 1993). Durability of wood and wood-based products
1993 - IRG/WP 93-20012
R Hüe

A review of environmental emissions from building and construction materials in comparison with preserved wood
2005 - IRG/WP 05-50224-11
A review of the public domain literature concerning emissions to the environment from materials which are used in the construction of buildings (e.g. Concrete, Asphalt, Galvanised Steel), in comparison with preserved wood, and a review of the approaches taken by the construction sector in assessing the risk from environmental emissions, in comparison with the approaches taken by the wood preservation sector.
E F Baines

Review of Mold Issues in North America and Mold Research at Forintek
2003 - IRG/WP 03-10458
Over the last decade, air quality in homes and workplaces has become a high profile issue especially in relation to mold, receiving considerable media, public and legal attention. Forintek Canada Corp. and the wood industry in general have experienced large increases in inquiries regarding mold and the suitability of wood as substrate for its growth. Because wet wood supports growth of fungi the public perceive wood used in building envelope as a major source of mold and this can affect wood’s image in markets and could be exploited by competitor industries. Forintek reviewed the existing and relevant information about mold, substrates that support its growth and the health issues associated with mold and water damaged buildings. Several projects and collaborative efforts with other groups have been initiated to deal with recognized knowledge gaps. This paper covers the history of mold hysteria, recent statements by authorities on mold and health and summarizes some of Forintek’s recent work. This includes: survey of mold and staining fungi on KD lumber; database of literature on mold, building materials and health; limiting conditions for mold growth, hidden mold and its movement into living spaces and a lab test method for mold resistance of wood products.
A Uzunovic, A Byrne, Dian-Qing Yang, P I Morris

Alkaline building materials and controlled moisture conditions as causes for dry rot Serpula lacrymans growing only in houses
1985 - IRG/WP 1272
Dry rot Serpula lacrymans ( Fr.) S.F. Gray is commonly found in houses, though never with certainly in nature, like other wood destroying fungi which grow both indoors and outdoors. In investigating series of dry rot instances it was shown that this fungus is always found in covered places, close to a moisture source, the distance being from 0 a maximum of 600 cm. Owing to the dry rot has been able to humidfy woodwork to the optimum condition of 20-30% wood humidity, while a lethal water content of 55% would be reached outdoors. At the same time the close presence of alkaline building materials, such as mortar, a clay layer, plaster or concrete has been observed in all instances, the average distance being from 0-100 cm. By neutralizing the dry rot fungus large production of oxalic acid the alkaline materials are able to adjust the pH to optimum levels. These two conditions are the reason why the dry rot fungus only occurs in houses.
J Bech-Andersen

Wood durability in the light of recent trends and research on the durability of building materials and components
2000 - IRG/WP 00-20195
Building-related research of today demonstrates a clear shift in focus from the design and production phases to usage and to the entire life time. A consequence is that the performance criteria of materials, components and of the entire building must be regarded over the life time rather than at the time of production or delivery. As one example can be mentioned the Building Construction Directive of the European Union were a number of essential requirements on buildings are stated. These requirements relate i. a. to safety and environment issues and are to be regarded as highly non-controversial. However, it is clearly stated in the Directive that these requirements must be fulfilled during the entire lifetime of the building. This means that the performance-over-time of each single material must be known and that a careful life time planning of the building must be introduced in the design and construction phase of the building project. To make this possible a lot of research is necessary and the research activity in this field is high. State of the art is presented every second year at the International Conferences on the Durability of Building Materials and Components, latest arranged in Vancouver in May 1999. In this paper the wood based and in special the chemically treated materials are discussed from the point of view of modern durability research approaches. The interaction between durability and environmental impact in a live cycle perspective is mentioned. A conclusion is that the research within IRG should be focused more on different building applications than has been the case so far. Examples of possible and necessary research projects are given.
K Ödeen

Serpula lacrymans the dry rot fungus. Revue on previous papers
1989 - IRG/WP 1393
It is found that the Dry rot fungus Serpula lacrymans grows in houses only because of its need for basic materials to neutralize the oxalic acid production or heavy metals which celate the oxalic acid. The average distance from the mycelium to the basic materials is found in average to be 14.2 cm with a variation from 0-100 cm. In contrast to Serpula lacrymans the Coniophora puteana and the Rigidophorus vitreus do not need calcium. The oxalic acid is found to hydrolyze the hemicelluloses and open for further break down of the celluloses. The excess oxalic acid is neutralized by calcium to the water insoluble calciurnoxalate which at last will be broken down by bacteria in the soil. The Dry rot fungus (Serpula lacrymans) (Schum ex Fr.) S.F. Gray, is found in houses and mines only in contrast to other wood destroying fungi which both grow indoors and outdoors in the nature.
J Bech-Andersen

Compatibility of deltamethrin with wood-finishing and construction materials
1993 - IRG/WP 93-30010
Under normal use conditions, treated wood comes to close contact with the structural components of a buiLding, and/or receives finishing, forming a new interface, which can affect the performance of a new product such as deltamethrin. To study this possibility, block-tests of Parana-Pine (Araucaria angustifolia), measuring 12 x 24 x 0.5 cm³ (with the largest dimension parallel to the wood-grain), received brushing treatment with deltamethrin and kerosene in two different concentrations: 0.02% (w/w) and 0.04% (w/w). After 20 days under laboratory conditions, the block-tests received a superficial finishing with poliurethan varnish, enamel paint, oil paint (alkidic) and latex paint and were fastened in close contact, through rubber band, with bricks, building cement, concrete blocks and plaster. A set of pieces made up of these construction materials was treated with deltamethrin in the same concentration as mentioned above, forming a reference series. The test against dry-wood termites (Cryptotermes brevis) was carried out 21 months after the treatment. The deltamethrin proved to be very effective in wood protection, independently of the finish used and the type of construction material in contact with the wood.
E S Lepage

Water Absorption of Various Building Materials and Mold Growth
2008 - IRG/WP 08-10657
Mold growth is a major problem for house owners, as it often occurs on the surface of building materials in damp houses. The principal method to control mold growth on building materials is to prevent water penetration into the materials. A study was recently conducted to determine water absorption rates of different wood species and panel materials used as building materials, when water intrusion occurs. The results showed that solid wood absorbed the least quantity of water among the building materials tested. Upon exposure to water for 7 days, the moisture content (MC) of solid jack pine, black spruce and balsam fir were found to be less than 24% when exposed on one side of the lumber and less than 57% MC when exposed on all sides. Among the three wood panels tested, medium density fiberboard (MDF) and oriented strand board (OSB) had higher water absorption rates, over 70% MC when exposed to water on one side of the panel and over 100% when exposed on all sides. The water absorption rate of plywood lay between that of solid wood and composite panels. Samples of other materials tested, such as gypsum board, fiberglass and ceiling tile, almost reached their saturation point in 1 hour upon water intrusion on all sides of the materials. Most panel samples exposed to water on one side were affected by mold in 7 days; on the other hand, the samples exposed to water on all sides were not affected by mold, because of their very high moisture content.
Dian-Qing Yang

Drying Rates and Mold Growth on Various Building Materials under Different Environmental Conditions
2010 - IRG/WP 10-20454
Mold growth on building materials is a major problem for homeowners. The most suitable method to control mold growth on building materials is to utilize design features, construction tools and practices that prevent moisture accumulation, and keep the wood as dry as possible. In order to achieve this, engineers and homebuilders have to know the effects of various temperature and moisture conditions on water accumulation and drying speed of various building materials, and the rates at which mold grows in a particular environment. A study was recently conducted at FPInnovations-Forintek Division to determine drying rates and corresponding mold growth on building materials such as oriented strand board (OSB), plywood, fiberboard, gypsum board, fiberglass insulation material, ceiling tile and several Canadian wood species lumber, under different environmental conditions. The results showed that, without ventilation, the sample moisture loss was slow and mold growth was found on test materials that were dried at 72% RH or higher, after 4 days. With ventilation, the drying rates of the various materials were much faster than without ventilation, and were not significantly affected by increasing the temperature from 20°C to 25°C. No mold growth was found on most materials that were dried with ventilation at 64% RH or less.
Dian-Qing Yang

Communities of mold fungi on flooded building materials
2013 - IRG/WP 13-10799
A small building built to residential code was flooded using farmland pond water to a depth of two feet at Tuskegee University. The building was drained and left enclosed for an additional three weeks. A total of 168 material samples were removed either immediately after opening (wet) or seven months after flooding (dry). Wall materials sampled included fiberglass batt insulation, gypsum wallboard, wood stud, plywood panels, vinyl siding, and house wrap and were analyzed by cloning and sequencing to identify the mold species present both above and below the water line. The vinyl siding and house wrap had the lowest mold growth while the batt insulation had very high quantities of mold, followed by the paper siding of the gypsum. The common types of molds present included Aspergillus, Chaetomium, Fusarium, Trichoderma, and Stachybotrys. The different molds were analyzed for presence on the different types and components of wall materials in areas exposed above and below the water line. In addition, real-time PCR quantitated selected mold species on different building materials. The mold species found in the highest concentration were Aspergillus fumigatus, Paecilomyces variotii, Chaetomium globosum, and Stachybotrys chartarum. The batt insulation supported the highest concentration of mold after flooding, followed by the wood stud, plywood sheathing, and gypsum wallboard. The highest level of mold on the dry materials was Aspergillus fumigatus on the dry wood stud and Stachybotrys chartarum on the dry gypsum. The focus of the research was to show that flood waters can penetrate into wall cavities of a home and the different wall materials become a substrate for different molds to develop, which potentially cause problems for some susceptible individuals.
F Skrobot III, H Aglan, S V Diehl

Method for determining the critical moisture level for mould growth on building materials
2013 - IRG/WP 13-20530
The natural conditions of relative humidity (RH) and temperature (T) in different parts of a building is rarely constant over time. Instead, RH and T often vary cyclically and may pose a risk of mould growth as these conditions are the two key environmental parameters that controls mould growth. Consideration to both humidity and temperature conditions and the susceptibility to mould in a material enables to minimize the risk of future mould damage. The critical moisture level is to be regarded as a temperature dependant material property. As building mate¬rials vary widely in their resistance for mould growth it is not possible to state a critical moisture level of a material without performing tests. The overall aim of this project was to find a way to determine at which level of RH different building materials tend to develop mould growth in order to provide a basic knowledge of the process of designing buildings with low risk of mould growth in accordance with the Swedish building regulations. The results of laboratory tests, together with results from a long field test formed the basis for a new method. This method is designed to evaluate the critical moisture level for mould growth on clean building materials at one specific temperature. In the method, four sets of 7 specimens for each building material are infested with mould spores and then incubated in four levels of relative humidity at 22°C during 12 weeks. During these weeks mould growth analyses are per¬formed regularly. The critical moisture level at the specific temperature is defined by the tested levels of relative humidity. Critical moisture levels at other temperatures may be calculated by using a formula given in the method.
A Ekstrand-Tobin, P Johansson, G Bok

Communities of mold fungi in moisture damaged building materials
2014 - IRG/WP 14-20542
The critical conditions needed for the development of mould and decay fungi have been modelled for different building materials. However, current knowledge of indoor microbes growing on building materials relies on culture-based methods and more advanced molecular biological techniques should be employed to study the complex microbial communities in building materials. In this paper molecular biological techniques were optimized and used to study microbial diversity in building materials exposed to different moisture conditions. Different naturally contaminated and inoculated building materials were exposed to different humidity conditions (relative humidity 90% and 98%) in laboratory-scale experiment. The DNA extraction method was optimized to different building materials and microbial communities were studied by fungal ITS region targeted PCR-DGGE and sequencing. Fungal communities differed between building materials and humidity conditions. In RH 90% the majority of the sequences obtained belonged to genus Aspergillus. As expected, in RH 98% the fungal community was more diverse containing e.g. genera Penicillium, Aspergillus and Oidiodendron. The fungal diversity was highest in wood-based building materials.
E Sohlberg, H Viitanen

Applicability of wood durability testing methods to bio-based building materials
2015 - IRG/WP 15-20561
It is well known that organic materials may be susceptible to attack from a range of fungal organisms and any bio-based material used in locations where there is the possibility of microbiological activity must be expected to be able to withstand or prevent such attack. There are a wide range of test methods and standards in place to test susceptibility although most of these test individual components such as wood or panel material. A wide range of old and new bio-based materials and novel construction techniques are showing an increase in use in new building and in the restoration of old buildings. These materials need to be assessed against microbial activity to determine if they are suitable for use in a particular area. Standard wood decay test methods are widely known and would seem applicable to many of the materials being used – especially where wood based products are used. However, due to their structure certain testing problems can arise. This paper seeks to test a variety of building materials, including sheep’s wool, mineral wool, hemp, wood fibre, cellulose flakes and assess the suitability of the testing regime on these materials. The method selected was the wood panel testing method DD ENV 12038, with some modifications to measure the extent of fungal growth as well as decay. The results show that although there was significant growth of the fungi through test samples only the lignocellulosic materials showed any appreciable decay. It was also noted that for some of the samples the structure of the material e.g. very thick or particulate fill, made the test sub-optimal.
S F Curling, B K Stefanowski, E Mansour, G A Ormondroyd

Performance of bio-based building materials – viewpoints from the first year of COST Action FP1303
2015 - IRG/WP 15-20572
Maintaining and expanding the market potential for bio-based building products in indoor and outdoor construction uses remains a key activity for industries in the forestry and biotechnological sector, particularly in Europe. Whilst there are ongoing activities within IRG for collecting and populating a database on performance on wood, the performance data for many other (i.e. non-wood) "environmental friendly" building materials are lacking as well as suitable comprehensive test methodologies to determine their resistance against mould, stain, and decay. The similarity in terms of decay hazard, resulting response on climatic loads and thus performance of different bio-based building materials has not yet been recognised adequately, and in order to overcome this problem within Europe, COST (Cooperation in Science and Technology) established the Action FP1303 entitled “Performance of biobased building materials”, which from 2013-2017 will provide a platform for networking and scientific exchange between different disciplines, such as material sciences, wood technology, biology, biotechnology, building physics and engineering. Through the activities in this Action, there will be a coordinated effort to put the issue of biodegradability of organic building products on the agenda, combined with consumer demands and preferences. These will help define service life prediction and performance models, will consider aesthetical aspects as well as the functionality of building assemblies. These will ultimately contribute to the control and prevention of any imminent threat to use bio-based building materials, which in turn could severely damage a pan-European low carbon building agenda. This paper outlines some of the activities undertaken within the first year of the Action, and describes some of the planned activities in the coming years.
D Jones

Modelling the performance of bio-based building materials
2016 - IRG/WP 16-20582
The ‘bio-based economy’ represents a growing area of development globally and covers a wide range of building materials including wood and wood-based products. A ‘bio-based’ material is intentionally made from substances derived from living (or once-living) organisms. In this context it means that the materials and products are made from renewable resources, with the criteria that a renewable resource recovers faster than it is drained, in contrast to many mineral and fossil resources. Their successful use in various applications in the building sector requires sufficient performance and reliable performance data are needed. A key instrument for predicting the performance of building materials on the base of test and survey data are models. Performance modelling is therefore an important issue within IRG-WP – in particular addressed within WP 2.1 ‘Prediction of Service Life’ as well as for COST Action FP 1303 ‘Performance of Bio-Based Building Materials’. On occasion of the 47th Annual Meeting of IRG-WP a special session on ‘Modelling’ will be held jointly with COST FP 1303. Exposure, decay, and resistance models related to wood and other bio-based building materials will be presented. Cross links between disciplines are sought and shall be intensified such as between material science, chemistry, building physics, wood and fiber technology, polymer science, biology, mycology, entomology, civil engineering, and architecture. This paper provides an overview about modelling approaches and applications of performance models for design and performance classification. Major challenges related to performance modelling are highlighted and discussed such as quality and availability of data for modelling, the variability of input and output variables, the decay-type specificity of models, and their verification.
C Brischke

The durability of manufactured structural building materials
2016 - IRG/WP 16-40718
The projected market potential for Engineered Wood Products such as CLT (cross laminated timber) is very positive however, potential prolonged rain leakage or moisture exposure during construction and in-service could pose considerable concern for its durability and reputation. This research was conducted to assess the decay resistance of CLT and OSB (oriented strand board) in an accelerated trial. This testing method is used in establishing the effectiveness of wood products in framing subject to intermittent wetting. The results showed untreated OSB and CLT were very susceptible to decay. However, in the case of CLT, decay can be prevented by surface application of boron preservative. There is a need to harmonise Standards for CLT and OSB timber used in building.
T Singh, D Page

The Environmental Impact of Timber Products Compared to other Building Materials - A Survey of Published Environmental Product Declarations
2016 - IRG/WP 16-50314
One of the positive aspects of using wood in construction is the environmental benefits that this can potentially bring. However, manufacturers of all construction products and materials make claims about the ‘environmental friendliness’ of their products, making it exceedingly difficult for the end user to make informed choices about the advisability of using one product over another. This study presents an analysis of the published environmental product declarations (EPDs) of timber products (fibreboard, particleboard, oriented strandboard, glulam/laminated veneer lumber, sawn and dried timber) and compares this data with that published in the widely available and quoted University of Bath Inventory of Carbon and Energy (ICE) database. Comparison is also made with some common non-biogenic building materials (concrete, brick, cement and steel).
C Hill, J Dibdiakova

Laboratory test to determine the effect on durability of combining biobased building materials with timber in construction
2017 - IRG/WP 17-20604
The use of Structural Insulated panels is a construction approach that is seeing more abundant use and is becoming a widely available method. Preformed units are usually a composite structure which often include a range of bio-based materials such as timber, wool or straw. Traditional laboratory based wood decay tests do not take into account this combination of biobased materials and it may be possible that non wood materials such as plant or animal fibre insulation could influence the durability of adjacent wood elements by synergistic mechanisms. One method may involve the insulation material acting as a moisture reservoir or moisture buffer for wooden structural elements with a consequential effect on their durability. This paper details an experimental approach to determine if there could be such an effect, using a modified form of existing wood decay testing methods. The test utilises an agar jar approach with a pad of fibrous insulation e.g. wool or hemp placed between the inoculated agar and a wood block. Results show the effects of the type of insulation used on the moisture content and decay of the test blocks. It is shown that moisture was able to pass through the insulation to varying degrees to be absorbed by the wood blocks. Fungal mycelium was then able to grow through some of the insulation materials to attack the wood. The test show that wool for example appeared to hold water away from the wood samples and reduced subsequent decay. Hemp however, did not prevent water access to the wood blocks and in fact enhanced decay of the blocks.
S F Curling, G A Ormondroyd

Service Life Forecasting and Planning – Why, and Concepts to do it
2017 - IRG/WP 17-20625
The importance of the building and construction sector in society cannot be overestimated. It is globally the major industry sector, a main contributor to gross domestic products, a dominant employer, and the main consumer of material resources and energy. The environmental impact of constructing, running and demolishing the built environment is huge. The products of construction are normally long-lived works, crucial for social and economic development, and for improving the living environment. Buildings and infrastructures are subject to changes over time, in performance as well as in expectations. Renovation, re-build, and refurbishment is a major part, in many nations periodically dominating, of building and construction activities. All existing materials meet and are expected to efficiently co-act in the resulting buildings and civil engineering works. It is well known that the value chain in building and construction is complex, and the sector is in all nations dominated by very to extremely small companies. Few industrial sectors are in such need of standards and standardized approaches to support efficient processes and to ease trade of products and services. This is underlined by ever increasing sustainability requirements, e.g. energy efficiency in building concepts, ambitions to reduced resource consumption in building and construction, and to decrease emissions of green-house gases and negative climate effects. Building and construction is in addition largely a scene for political ambitions and economic control mechanisms, good and bad. This key-note contribution to the IRG annual meeting 2017 in Ghent gives an overview of theories and principles of service life prediction and planning in building and construction, and the resulting international and regional standards. The European regulatory work as a driving force is addressed. The international durability conferences, the DBMC´s, have over the years functioned as invaluable platforms for communication and scrutiny of ideas and research results and by that also strengthened the international standardisation work. The contribution will reflect why so is the case, and on some of the mechanisms.
C Sjöström

Preventivephysical barriers against subterranean termites species for building protection: How to implement innovative materials to reach efficacy requirements
2018 - IRG/WP 18-40845
As the European regulation dealing with the use of biocides (BPR) for preventive protection of buildings against subterranean termites is leading to more and more pressure on physico-chemical barriers currently used (PT18), some existing developments are focusing attention on physical biocides-free barriers. The main target is then to avoid the use of active ingredients, to stay out of the BPR scope and cancel the potential risk of health and environmental issues. Different techniques are already on the market displaying good efficacy on special areas where termites can be strongly aggressive, but are often applied and limited to some special implementation areas or potential paths for the termites. This kind of product is not dedicated to cover the whole surface of the building, contrary to biocides treated plastic films that are representing the core-market in France for example. The aim of this paper is to present two different biocides-free materials and/or techniques, which have been developed and tested recently in the company, and gave very promising results for being resistant to termites’ penetration and potentially protect building from subterranean species once implemented before construction. Two different types of preventive physical barriers were proofed at the lab scale according to NF EN 41-550 standard against Reticulitermes and fulfilled the efficacy requirements, with giving also information on the real behaviour of termites when exposed to this kind of material. Improving surface or mechanical properties of some materials can represent an interesting issue for better resistance of pest damages without using any active ingredients. Then, risks of loss of efficacy or potential contact of insecticide generally used in physico-chemical plastic barriers with users or the ground are minimal.
N Delourme-Fonseca, P Poveda, F Simon

Long service life or cascading? The environmental impact of maintenance of wood-based materials for building envelope and their recycling options
2018 - IRG/WP 18-50336
A major restraint in choosing bio-based materials (i.e. wood-based) for external use, is the lack of confidence that architects, designers and customers have toward these materials. In particular, the limit state of bio-based materials, which defines the frequency of maintenance operations, might be reached earlier for wood than for other materials (i.e. concrete). On the other hand, resource and energy scarcity together with increasing concern for climate change consequences are raising the demand for competitive bio-based materials in the built environment as substitutes for other energy-intensive materials. Therefore, novel and traditional protective treatments are used to improve the performance of woody materials for outdoor use. Nonetheless, the environmental and economic burden of such treatments is often unknown. The number of LCA (life cycle assessment) studies on the topic is low, with geographically sparse data and non-uniform assessment protocols. This study provides a novel approach to assess the in-service performance, maintenance requirements and end-of-service-life options for over one hundred bio-based materials for façades. The protection techniques of the materials under examination include: chemical modification, thermal treatment, impregnation, hybrid treatments, and surface treatments (bio-film, coating and nanocoating). Natural, untreated wood and composite materials such as wood-plastic composites are included as well. The in-service environmental performance is analysed by considering the amount of material, energy, water and waste that are used and/or produced to maintain one square meter of façade. The options for end-of-service-life include: panel manufacturing, pelletizing, animal bedding, liquefaction, insect conversion, fungal conversion, combustion, incineration, gasification and pyrolysis, anaerobic digestion, fermentation, composting and landfilling. For each material group, the possibility for cascading use is assessed. The overall goal is to increase the confidence in bio-based building materials by tackling environmental issues related to wood modification processes.
M Petrillo, J Sandak, P Grossi, A Kutnar, A

Performance of bio-based building materials – durability and moisture dynamics
2020 - IRG/WP 20-20666
When exposed to conditions favourable for decay, bio-based building materials can be susceptible to degradation. Their ability to withstand deterioration over time (performance) depends on the intrinsic or enhanced durability of the material as well as its wetting and drying behaviour. The effect of fungicidal components in wood is known since long. Other material characteristics, such as the material’s moisture dynamics and structure, are crucial as well in prolonging a material’s service life in outdoor exposure conditions. The importance of these other material characteristics should not be underestimated, as there are many opportunities to alter a material’s moisture dynamics and to optimize the structural design of engineered wood products and bio-based insulation products. In order to do so, it is necessary to understand how different material characteristics influence the performance. In this paper, we assess the moisture dynamics of oriented strand board (OSB), porous bituminized wood fibre board (PBF), radiata pine plywood (PL), thermally modified spruce (TMT) and two wood fibre insulation boards (WF-A and WF-B). With the ‘paste test’, we assess whether these materials contain fungicidal components affecting decay. Additionally, we assess how they perform in an adapted mini-block test. We are able to show that fungicidal components are not always of major importance for the durability of a bio-based building material. Some of the assessed materials have a remarkable moisture performance. We need to work towards specific moisture performance criteria and consider including them in performance classification.
L De Ligne, J Caes, S Omar, J Van den Bulcke, J M Baetens, B De Baets, J Van Acker

Biological assessment of bio-based phase change materials in wood for construction applications
2022 - IRG/WP 22-40935
Solid wood can serve multi-functionality for energy savings in buildings. The study reveals the results of bio-deterioration and degradation of solid Scots pine wood used to incorporate single or multicomponent fatty acid mixtures as bio-based phase change materials (BPCMs). The sapwood samples were impregnated with capric acid (CA), methyl palmitate (MP), lauryl alcohol (LA) and a mixture of coconut oil fatty acids and linoleic acid (CoFA-LA). The samples were tested against subterranean termites by an Italian species (Reticulitermes lucifugus), the wood boring beetle Hylotrupes bajulus and mould through a discoloration test. Tested against termites, the impregnated samples were significantly less susceptible to the attack than the controls, i.e. the tested BPCMs were resistant to R. lucifugus. The only test with MP terminated at the moment against H. bajulus showed positive results with no larvae survived. The mould discoloration test revealed that the wood impregnated with CoFA-LA was identically susceptible to mould discoloration when compared to the control, non-impregnated samples. This pioneer study verifies that solid wood employed for encapsulation of BPCMs for building purposes can serve identically or somewhat better than similar wooden building elements regarding attacks of the above microorganisms and insects. Such multifunctional building elements will be tested further in a pilot scale building to characterize better the durability aspects of the new materials.
S Palanti, A Temiz, G Köse Demirel, G Hekimoğlu, A Sari, M Nazari, J Gao, M Jebrane, T Schnabel, N Terziev

Evaluation of different wood by-products for sustainable building biomaterial production using fungal mycelium
2022 - IRG/WP 22-50373
As human population increases, the demand for new innovative, sustainable, and low impact construction materials also grows. Mycelium-based composites have shown to be an excellent alternative for traditional products ranging from low-density objects to semi-structural applications. They also present the advantage of using the waste streams from other productive processes as feedstock, enabling the upcycling of materials that can help us transition into a circular economy. In this study three different experiments were carried out: first the selection of the fastest growing fungal strains and the process’ temperature; secondly, three different grain spawn media were evaluated for inoculum production and the last one was a qualitative screening of mycelium growth in different wood by-products. G. lucidum, T. versicolor and P. ostreatus grown at 25 °C were chosen due to their fast-developing rate and mycelium density in comparison to P. eryngii and F. pinicola. For grain spawn production of these strains, a 1:1 mix of wheat and millet was found to be the best option to accelerate the mycelium growth rather than using the grains separately. Different 9x12x4 cm samples were produced using a variety of wood by-product substrates and the shortest production time and more visibly homogeneous material was obtained when growing G. lucidum on beechwood. However, other preliminary test demonstrated the great potential of mixed substrates for production times reduction. The next steps for this research include substrate optimization using mixed wood substrates and further characterization of the bio-composites including thermal conductivity and humidity resistance tests.
C Charpentier-Alfaro, M Poggerini, S Palanti, G Della Rocca, D Pellegrini, A Crisci

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