b'Other ImportantMeasurementsMost installers plumb the jambs, and attempt to levelthe header, but are often unsuccessful because thesill is out-of-level (even in new construction) and theydont compensate for this with shimming.Construction Standards accept out-of-level sills up to1/240th of the span.Translated into small dimen-sions, this allows each 32 span to be out of level upto 1/8. An average 6 foot picture window or gardenwindow can be out-of level over 1/4in a new home.In older homes, the situation can be worse due to LEVEL PLUMBsettling and softer building codes. Constructiondebris, nail heads, knots and splits in the subsill cancreate irregularities in the level of the sill on which Tapethe new window rests.The first solution is to shim the bottom of the windowunit to level, as long as shimming doesnt raise thesill to a point where water can leak under the sill torot the subsill or leak into the house.Because ashimming a sill can cause part of the window bottomto be unsupported, it is possible that the new win-dows sill can bend under the weight.And, in caseswhere there is a crown in the sill, shimming becomescomplicated considering the size and weight of themaster frame. The only stable and long-lasting solu- Cross Pointtion is to establish level across the entire sill prior toinstallation.Use some kind of shimming, hardeningfiller, or a rigid sub-sill.PlumbPlumb is measured with a Bulb Levelplaced on each jamb. Record how much one end SQUAREneeds to be moved away from the jamb to create aplumb conditionon each side. Plumb is often defined as vertical level. The sides ofthe opening must be vertical so as not to distort orskew the window or door frame. PLANAROut of plumb can render locks inoperable at worst,and difficult to operate at best. As with level, construction often accepts out-of-plumb, so while measurements of width and height may be relatively equal in the 3 recommended locations, itdoesnt mean the sill is level or the jambs plumb.Record the condition of the plumb of the jambs on aspecification sheet.PlanarPlanar is measured by temporarily anchor-ing a string diagonally from upper corner to oppositelower corner. The strings will touch in the centerwhere they cross, or they will not. If they touch,reverse which string is on the outside. If they ceasetouching, the distance between the strings where Careful Measuring and Checking is the differencethey cross will be the planar condition measurement. between successful installation and problems.Window Fitters Guide to Window Installation282020 AWDI, LLC Do not reproduce without permission'