b'CMU Curved-Top Installation with BuckInstalling Curved Windows in CMU Openings is a difficultprocedure because the concrete block, or even poured concrete lintel is difficult to make perfectly smooth andround, and join the rough opening jambs seamlessly.The applied buck is made from a flat stock - either 3/4thick or 1-1/2 thick and this stock is not easily bent to a shape.If it cant be bent well, the circular windowcannot easily mount weather tight and water and moisturepenetration resistance like the rectangular units can be.Fabricating the opening to accept a curved windowrequires on of two approaches:1. Kerfing the stock (as shown) by slicing a multitude of grooves in the surface2. Utilizing a free foam, cellular pvc stock which can be bent to a radius in a smooth fashion .Accommodating theCurved WindowThe Opening must be level, plumb and square, and themortar properly applied to allow no voids, cracks orclumps that might allow water infiltration.A proper sill must be accommodated either with a pre-castsill, or an applied buck with a sill pan installed as shown.Note: Florida Building Code Requires that products tested for wind and debris - especially for hurricane and high wind zones - be installed as they were tested.PrecastThis can mean anything other than a wood buck sill mayLintelvoid hurricane and wind approvals.PouredSillWindow Fitters Guide to Window Installation1322020 AWDI, LLC Do not reproduce without permission'