b'1. Plumb, Level and SquareProper Measurement and alignment of the opening is critical to proper install and operationPlumbOut of plumb can render locks inoperableat worst, and difficult to operate at best.Level -Out of level sills will distort the frame to anout-of-square situation. This will make it nearlyimpossible for the sash, which will be square at thecorners, to nest properly, lock properly, and seal out PLUMB PLANARwindow and moisture properly. Square -Determine square by measuring the cornerdiagonals (upper left to lower right, and lower left toupper right). Record both dimensions. The differencebetween them is the out of square condition. Morethan 1/8 may require re-sizing the new window.PlanarPlanar is measured by temporarily anchoring a string diagonally from upper corner toopposite lower corner. The strings will touch in thecenter where they crossor they will not. Reversethe strings. They should lightly touch either way. If not, this condition will indicate that one of the upper corners of the window is not flat in plane to the opposite lower corner. This will render the newwindow contorted in installation. CrownThis condition is where the center betweenthe jambs is higher than at the edges of the opening.Placing a window or door on a crowned sill can causethe interlocks to not meet properly; the panels to notslide properly on a sliding window or door, or willimpede the proper operation of a hinged door or window. Use the support blocks to level the support.BowThe opposite of Crown, a Bow will be a lowspot between the jambs. As with a crown, a depression can cause the sill of the window or door to deflect and impede proper operation and sealing/locking. The sill support must be level.TrapezoidWhile most openings have equal widthsand equal heights down and across the opening,occasional an opening can be wider at the top, or LEVELwider at the bottom. A trapezoidal effect can requireSQUAREa change in the width and/or height of the specifiedwindow or door.Bottom line- The new Tilt/Turn or Tilt and Slideproduct must be allowed to operate without being distorted to fit the opening in any manner. If you are using a wood buck, effort should be made tomake the buck (wood surround) perfectly Square.plumb and level. Take this work into considerationwhen ordering the size of the window or door to allow product undercut for support and shimming.This will then allow the new product top be installedand work properly. CROWN IN SILL BOW IN SILL UNLEVEL SILLWindow Fitters Guide to Window Installation 1172020 AWDI, LLC Do not reproduce without permission'