Abstract: According to the present invention, an assembly for shimming a construction member to an opening is provided. The assembly includes a plurality of stacked leaves made primarily of cellulosic material. The leaves have a shape with a uniform thickness, defining a pad presenting front and back surfaces. A strip is located on either or both of the front and back surfaces, the strip being releasable to expose an adhesive for attaching the pad to the construction member. The leaves are secured together by a binding to allow a selected number of the leaves may be manually peeled off the pad to shim the construction member within the opening. The present invention also provides an installation method for a door or window frame, which is fast and accurate especially for a prefabricated door or window unit. Another use is with cabinetry where limited access is possible on the back surface against a finished wall.