The next generation of mass timber panels is being made with wood rather than steel fasteners – with steel nails, screws and bolts replaced by dowel-shaped joints made from hardwood. That is according to StructureCraft – which, through its newly launched DowelLam division, is ramping up production of acoustic dowel-laminated timber (or ADLT) from its state-of-the-art facility in British Columbia.
Set to debut at the International Mass Timber Conference (IMTC) in Portland next month, where StructureCraft’s Vice President and Head of Engineering Lucas Epp will headline a panel discussion on the new barriers to mass timber adoption – the engineer-builder has used the system in more than 100 projects across North America – from Microsoft to Princeton University, and Hines Real Estate’s T3 portfolio.
As the first all-wood mass timber panel, DLT uses hardwood dowels to bond the edgewise of softwood lumber stands together – allegedly stronger, cheaper and greener than cross-laminated timber and ideal for floors, roofs and walls. As the only large-scale supplier of the product in the North American market, Structurecraft said, “ADLT is a high-performance panel that integrates a built-in acoustically absorptive membrane into the underside of the DLT, allowing mass timber to remain exposed while meeting structural and noise reduction demands.”
“We couldn’t be more thrilled to launch DowelLam – a brand dedicated to the design and supply of dowel laminated timber across North America,” said Derek Autenrieth, DowelLam’s new Sales Manager: “DLT has become a well-established mass timber product over the last eight years, there is no better stage than the IMTC to showcase its broad application and capabilities across all product types.”
Dowel-shaped fasteners can trump steel in wall-to-floor connectors.
Last year, Wood Central reported that dowel-shaped connectors were the ideal solution for low-rise and mid-rise construction, with a study published in the Journal of Building Engineering revealing that floor-to-wall, wall-to-wall, and floor-to-floor proved, beyond doubt, that hardwood dowels offer higher strength stiffness compared to traditional screws.
According to lead researcher Aivars Vilguts, “hardwood dowels have become one of the most popular fasteners for wood-to-wood joints in recent years,” adding that “the most widely used hardwood dowels are Red Oak (in the United States) and Yellow Birch.” Mr Vilguts, who is a postdoctoral associate at Virginia Tech in the United States, added that “experimental testing suggests that hardwood dowel joints have comparable or even superior performance than screws.”
The research, funded by the US government’s Harnessing Emissions into Structures Taking Inputs from the Atmosphere (HESTIA), found that Red Oak dowels were twice as strong as normal screws. Or, as Mr Vilguts put it, “for the same shear loading in the half-lap joint, we would need to use on average twice as fewer hardwood dowels as screws.” In addition, it also found that when tested under extreme conditions – such as earthquakes – the Dowell-based connectors “still perform in an elastic stage without any yielding.”
- To find out more about StructureCraft and how it is using ADLT to build some of the world’s most amazing timber projects, including Brazil’s largest timber domed tennis court, click here for Wood Central’s special feature.
