Abstract: A surprisingly durable, strong, outdoor window shutter without functional louvers or slats, which is substantially comprised of polyvinyl chloride, is described. The shutter preferably has a center panel onto which is laminated two back vertical members. This is preferably in the shape of a rectangle with two opposite edges into which stepped projections have been cut. The shutter preferably also has two vertical side members, each having a channel containing a strengthening rod. The vertical side members have stepped arms which fit closely over the stepped projections. Mortise and tenon joints are formed at the point of connection between the stepped projections and the stepped arms. The strengthening rods and the mortise and tenon joints serve to strengthen the shutter. Additional strength is provided by horizontal members affixed to the top, middle and bottom of both the front and the back of the shutter. These shutters have excellent structural rigidity and can last for many years.