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Durability of Cross Laminated Timber Against Termite Damage

https://research.thinkwood.com/en/permalink/catalogue1967
Year of Publication
2018
Topic
Serviceability
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
França, Tamara S.F.A.
Stokes, C. Elizabeth
Tang, Juliet
Year of Publication
2018
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Serviceability
Keywords
Subterranean Termites
Mass Loss
Visual Rating
Conference
International Convention of Society of Wood Science and Technology
Research Status
Complete
Summary
Mass timber is a category of framing components that can be built with a variety of materials. Engineered wood products have become the backbone of the mass timber movement. Some of the most common mass timber structural elements used in buildings are glue-laminated beams (glulam), laminated veneer lumber (LVL) and cross laminated timber (CLT). However, wood is a natural material which is susceptible to decay and termite attack. Subterranean termites cause billions of dollars in damage each year and their primary food is wood. In the past few years, there has been an effort to expand the use of mass timber products, especially CLT products, in the U.S. However, to date no termite infestation study has been done for the product. This study evaluates the natural resistance against termites of three wood products available in the market: untreated pine, CCA treated pine, and CLT. Some necessary modifications to the AWPA E1 standard were made in order to test the bigger samples (CLT blocks). The results indicate that CLT is susceptible to Coptotermes formosanus attack.
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Evaluation of Cross-Laminated Timber Resistance to Termite Attack

https://research.thinkwood.com/en/permalink/catalogue1964
Year of Publication
2018
Topic
Serviceability
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
França, Tamara S.F.A.
Stokes, C. Elizabeth
Tang, Juliet
Year of Publication
2018
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Serviceability
Keywords
Subterranean Termites
Mass Timber
Mass Loss
Visual Rating
Conference
American Wood Protection Association Annual Meeting
Research Status
Complete
Summary
Cross laminated timber (CLT) is a relatively recent addition to the North American timber construction market. CLT has been successfully used for construction in Europe and, in the past few years, manufacturers have looked forward to expanding the use of this product into the North American market. However, no termite susceptibility experiments have been published for the product and no standards exist for testing of the CLT and other mass timber products against termites. It is extremely important to evaluate the resistance to degradation of CLT, especially if the manufacturers are trying to implement this product in areas where the occurrence of termite infestation is high...
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Ongoing Field Evaluation of Douglas-fir Cross-Laminated Timber in a Ground Proximity Protected Test in Mississippi

https://research.thinkwood.com/en/permalink/catalogue1958
Year of Publication
2018
Topic
Serviceability
Material
CLT (Cross-Laminated Timber)
Author
Mankowski, Mark
Shelton, Thomas
Kirker, Grant
Morrell, Jeffrey
Year of Publication
2018
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Topic
Serviceability
Keywords
Douglas-Fir
Treated Wood
Termites
Conference
American Wood Protection Association
Research Status
Complete
Summary
Current design standards incorporate the use of preservative treated and naturally durable wood where conditions are suitable for deterioration, but treatment options for mass timber products, particularly, cross laminated timber (CLT) remain to be addressed. Termiticide treatment is a necessity for CLT structures, especially in southeastern climates. Wood species currently used to fabricate CLT are non-durable, and current design standards do not properly address incorporation of preservative treatments into these systems. In this study, 12” x 14” x 4” Douglas-fir CLT pieces were installed in a ground proximity protected test at the Harrison Experimental Forest (HEF), (Saucier, MS). Test samples were placed in sets of two in 30” x 30” subplots on bricks approximately 3-4” above soil and covered with ventilated waterproof covers. A total of 20 test pairs (40 total samples) with four different treatments were installed. The treatments consisted of a soil termiticide treatment, a preventive borate spray treatment at initiation, a remedial treatment with the spray-on borate one year post initiation and untreated controls. Soil below five pairs of samples was treated the with a soil termiticide (Termidor® SC). For the preventive borate at initiation treatment, one sample per pair of five other sets was treated with a spray-on borate preventative treatment (Bora-Care®). The remaining ten pairs were left as untreated controls. Temperature and humidity inside some of the covered units is being monitored throughout the test. The ten control sets will be examined for termite attack 12 months after installation. Five of the attacked sets will be treated with spray-on borate as a remedial treatment for active termite attack.
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Ongoing Termite Studies on Cross Laminated Timber (CLT) Panels

https://research.thinkwood.com/en/permalink/catalogue2395
Year of Publication
2019
Topic
Serviceability
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
Stokes, C. Elizabeth
França, Tamara S.F.A.
Tang, Juliet D.
Year of Publication
2019
Format
Journal Article
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Serviceability
Keywords
Subterranean Termites
Mass Timber
Mass Loss
Laboratory Assay
Research Status
Complete
Series
Proceedings, American Wood Protection Association
Summary
The development of composite mass timber products in the late 20th century continues to generate new developments in the design and production of multi-layer wood products in a wide variety of orientations and for a wide variety of uses. In the US Congress’ Agricultural Act of 2014, provisions were specified in Section 7310 to establish a series of priorities for research into the needs of the forestry sector. Specifically, collaborative research efforts into the increased use of CLT in support of the expansion of this portion of the forest products industry were addressed. Cross laminated timber products have been included in updates to national and international building codes, and new production facilities continue to come online. WoodWorks (2019) reports that 105 CLT based construction projects are in construction or completed, and 200 are in the design process. These projects are scattered across the United States, including in the highest areas of decay potential (Figure 1). Mississippi State University Department of Sustainable Bioproducts has several ongoing projects to investigate the durability of CLT under various conditions. These are partnerships with other investigators, primarily with USDA Forest Products Lab personnel, and are housed at both MSU Department of Sustainable Bioproducts facilities in Starkville, MS as well as Forest Products Lab locations in Madison, WI, McNeill, MS, and Saucier, MS. CLT is being tested in several different formats and in test pieces of different sizes. In an ideal situation, CLT panels would be tested at their full size, however, the time it would take to do so, and the logistics of handling pieces of typical size is prohibitive for rapid assessment of the product. Assessments of CLT to date have focused on examining the durability of CLT when exposed to hazards that occur in the high hazard zones of deterioration, such as fungi, termites, and natural weathering. This report describes the collaborative testing of CLT against termite infestation and damage.
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Remote Detection of Termite Activity in Wooden Bridge Structures

https://research.thinkwood.com/en/permalink/catalogue1837
Year of Publication
2018
Topic
Serviceability
Application
Bridges and Spans
Author
Green, Frederick
Boardman, Charles
Munson, Robert
Organization
Forest Products Laboratory
Year of Publication
2018
Format
Report
Application
Bridges and Spans
Topic
Serviceability
Keywords
Remote Detection Methods
Acoustic Emission
Light Transmission
Moisture Monitoring
Termites
Research Status
Complete
Summary
Wooden bridges, such as historic covered bridges or modern railroad and highway bridges, can become susceptible to subterranean termite feeding. This can result in weakened structural integrity of the wooden members of these bridges, and possibly even structural failure if damage is not discovered early and control measures are not implemented. The goal of this study was to evaluate the use of various remote detection methods, including acoustic emission sound waves, interruption of light transmission, radar and microwave transmission, moisture monitoring, and changes in gas concentrations in detecting termite activity. Successful methods for remote termite detection would reduce the number of annual site visits required to assess these structures and provide an early warning for potential damage, which could significantly reduce repair costs.
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Treatability of Cross Laminated Timber With a Low Moisture Uptake Surface-Applied Penetrating Process for Applying Termiticides

https://research.thinkwood.com/en/permalink/catalogue2642
Year of Publication
2014
Topic
Serviceability
Material
CLT (Cross-Laminated Timber)
Author
Stirling, Rod
Morris, Paul
Organization
FPInnovations
Year of Publication
2014
Format
Report
Material
CLT (Cross-Laminated Timber)
Topic
Serviceability
Keywords
Termites
Preservative Treatment
Panels
Hem-Fir
Research Status
Complete
Summary
Cross-laminated timber (CLT) may require preservative treatment in markets with severe termite hazards. Given the size of CLT panels, conventional pressure treatment would not be feasible. We therefore assessed the treatability of CLT panels with an alternative low moisture uptake surface-applied penetrating process for applying termiticides. Hem-fir panels were selected for the initial tests on the grounds that western hemlock and amabilis fir are relatively treatable. Nine test panels were dip treated and stored for 7, 14, or 21 day activation periods. Borate retention ranged from 1.2 to 6.5 kg/m3 and penetration ranged from 3 to 9 mm. Longer activation periods did not result in improved penetration. Greater penetration would likely be needed to meet performance-based standards.
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Utility of Image Software in Quantification of Termite Damage on Cross-Laminated Timber (CLT)

https://research.thinkwood.com/en/permalink/catalogue2344
Year of Publication
2019
Topic
Serviceability
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Author
França, Tamara S.F.A.
Stokes, C. Elizabeth
Tang, Juliet D.
Arango, Rachel A.
Year of Publication
2019
Format
Conference Paper
Material
CLT (Cross-Laminated Timber)
Application
Wood Building Systems
Topic
Serviceability
Keywords
Termites
Mass Loss
Image Analysis
Conference
International Nondestructive Testing and Evaluation of Wood Symposium
Research Status
Complete
Summary
Cross Laminated Timber (CLT) is part of a new generation of engineered wood products that are now widespread across Europe, Australia, and Canada. As this trend is now growing in the United States, manufacturers are looking to expand the use of CLT into the North American market, which includes states located in the southeastern U.S. As this region is known to have an increased risk of termite attack, standards should be developed to evaluate termite damage on CLT products prior to extensive use of the product in this region. However, existing standard test methods cannot be applied directly to CLT specimens as current standard test sample sizes are too small to adequately represent CLT constructed materials. Therefore, larger sample sizes were examined to determine resistance of CLT products against termite attack. Large sample size made it difficult to evaluate termite damage using weight loss as a variable as termite damaged specimens showed relatively low weight loss values. The objective of this work was to examine the use of the image analysis software, ImageJ, in determining the extent of termite damage on CLT blocks. Results showed that evaluation of void volume percent could be used in conjunction with weight loss and visual rating to obtain a more accurate measurement of overall termite damage in CLT.
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7 records – page 1 of 1.