Potential of Hardwood Lumber in Cross Laminated Timber in North America:A CLT Manufacturer's Perspective

Abstract

The objectives of this research are to study the current manufacturing practices for Cross Laminated Timber (CLT) in North America and record manufacturers’ perspectives to identify the opportunities and challenges of using hardwood lumber in their existing set-up. Face-to-face interviews and industry visits were used to collect data on current production practices and manufacturers’ opinions regarding the potential use of hardwood lumber in CLT manufacturing. To date, only two United States-based CLT manufacturers have used hardwood lumber in specific projects. The only issues with using hardwoods for the two manufacturers, compared to softwood operations, were quick dulling of cutting tools because of higher hardwood density and a longer pressing time. Other factors, such as moisture content, various dimensions of the lumber, and the caustic nature of some species, were highlighted as limitations for the use of hardwood lumber in CLT panels. The primary concern of the manufacturers was the availability of hardwood lumber in the required quality and quantity. While there is abundance of non-dimensional grade hardwood lumber available, none of this hardwood lumber can be used in its current state, as it does not meet the minimum requirements for CLT manufacturing, or those that meet the specifications are of higher grade and are not cost-competitive. Using non-dimensional grade hardwood lumber requires additional value-added and material removal work, and such work would significantly reduce productivity and increase costs. All CLT manufacturers agreed that the first step to the successful implementation of hardwood or hardwood-softwood hybrid CLT would require the production of dimensional grade hardwood lumber by hardwood sawmills.