Lintels in a dry stacking system for masonry

For over ten years the number of skilled masons has been dropping. A large drop was due to the collapse of the housing bubble in 2008. The trend has continued, as the aging workforce is leaving the field. Educators have not been able to enthuse enough people to fill the ranks left by the retirees. The result is delays in construction, as contractors struggle to find enough workers. Also, the hourly wage of masons has increased, compared to similarly skilled jobs. To mitigate the problem, several dry stacking systems for masonry have come on the market in recent years. Dry stacking eliminates the skill necessary to make masonry, by more closely controlling the interfaces between components. By doing this dry stacked masonry tend to lose some of the abilities of its traditional cousin. One of these is the ability to span a a facade opening, without hanging the masonry from the inner cavity-leaf. The objective of this research is to investigate the possibilities to span a façade opening using dry stacked masonry. The investigations focus on a single system, namely H-block by the company Drystack bv. The result is seven typologies elaborated in varying depth. The typologies range from integrating existing lintels into H-block, to the investigation of the structural potential of masonry itself. One typology was chosen to elaborate on further. This typology uses vertical prestress to create various internal arches in the masonry to span the facade opening. The report describes the presumed workings of this lintel and concludes with a full-scale prototype.