
, Joist From Wikipedia , the free encyclopedia Jump to : navigation search This article does not cite any references or sources Please help improve this article by adding citations to reliable sources Unsourced material may be challenged and removed December 2009 Look up joist in Wiktionary , the free . dictionary A roof made with a concrete slab with concrete joists In architecture and engineering a joist is one of the horizontal supporting members that run from wall to wall , wall to beam , or beam to beam to support a ceiling roof or floor It may be made of oriented strand board plywood wood steel or concrete Typically , a beam is bigger than a joist , which is often supported by beams and laid out in repetitive . patterns The wider the span between the supporting structures , the