One option for a tiki bar roof is thatched palm fronds. This will give your bar an authentic tropical feel. If you live in an area where palm fronds are not readily available, you can purchase them online or at a local party supply store. Another option is to use artificial thatching, which can be found at most home improvement stores. Be sure to secure the thatching material well so that it does not blow away in strong winds. Another popular tiki bar roofing material is corrugated metal. This is a durable option that will provide plenty of shade and protection from the elements. You can purchase pre-painted corrugated metal sheets or paint them yourself to match your bar's décor.