Project contact is Jacob Mans at the University of Minnesota
As the acceptance of cross-laminated timber (CLT) grows among commercial and institutional clients, the hospitality industry, in general, has been hesitant to adopt CLT. This reluctance is linked to several real and perceived factors. One, the industry has fire safety and fire rating concerns with the construction system; these concerns have been largely addressed through independent research and building code updates. Two, the industry is concerned with the acoustic rating of standard CLT panels, which do not currently meet the elevated performance standards of the hospitality industry – specifically the sound transmission class (STC) rating -- and will require additional design research. Three, the industry is concerned with the aesthetics of the system and the dual challenges of exposing wood and simultaneously integrating Mechanical Electrical and Plumbing (MEP) systems. Image, brand identity, and indoor air quality are all key variables that factor into whether this rapidly-growing industry adopts CLT as a viable system for hotel construction. There is an opportunity to reframe these individual challenges as a collection of assets in order to provide a holistic solution that can will demonstrate the feasibility of CLT within the hospitality industry.
This grant will address these barriers and to facilitate the increased utilization of CLT within the hospitality industry. Such utilization has the potential to divert a substantial amount of fuel from federal forest and timber lands and to sequester its embedded carbon in buildings. Market analysis estimates that 715 hotels of 8 floors or lower (the target size for this project) will be built in the United States in 2020. If constructed out of CLT, this market represents approximately 94 million board feet of potential wood utilization through CLT per year (over 1 million metric tons of sequestered CO2). The opportunity to capture a fragment of this market warrants feasibility research to prove the viability of CLT for the hospitality industry.
The University of Minnesota and DLR Group will work with CLT manufactures and established hospitality partners to construct a modular hotel room prototype that can test acoustical and MEP systems integration strategies – as well as spark future research projects. This experimental apparatus will also double as a show unit to educate possible users and developers of the potential for a mass timber hotel. In addition to developing, constructing, and testing the prototype, the team will develop informational materials and a detailed cost analysis of the project that will encourage hospitality partners to implement these ideas with confidence.
The objective of this study was to examine new attributes and conduct economic analyses for composite CLT (CCLT) and value-added appearance-based CLT products manufactured with varying substitution of softwood lumber with structural composite lumber (SCL) and hardwood lumber. Incentives for including such materials could be aesthetic, structural and economic.
Structural and aesthetic property assessments were carried out on prototype CLT panels. Multiple CLT panel configurations (17) were evaluated to assess the effects of including hardwood and SCL materials in the layups. Presence of hardwood in the panels’ configuration generally led to higher checking and density. Because of the higher shrinkage of hardwood, the bondline suffered from more delamination. A lower density hardwood (aspen) was included in some configurations and exhibited a greater direct compatibility with current Canadian manufacturing process. Changes to this process, such as selecting a hardwood specific adhesive may lead to improvements.
Project contact is Arijit Sinha at Oregon State University
This project will undertake a comprehensive analysis of the effects of water exposure, in various forms, on mass timber building elements. Water intrusion is mostly commonly seen during construction, but can also occur during failure of roofs or external facades or as a result of internal plumbing failures. The research team will employ CAT-scan imaging, vibrational testing, non-destructive and small-scale physical tests to assess the effects of moisture intrusion and any subsequent biodegradation on the structural performance and aesthetic characteristics of the building elements and connections. This analysis will include investigating the effects of cracking and delamination that may occur as a result of wetting and drying. The project will facilitate development of guidelines on moisture control during construction, help identify suitable methods for protecting mass timber products where required and highlight design features that can be used to mitigate the risk of fungal and insect attack.