Installation method and system for a closure unit

A method of installing a closure unit in a rough opening, comprising the steps of:

• forming a longitudinal recess in at least a portion of a perimeter edge of a frame on the closure unit;
• releasably coupling an attachment member of an adjustable shim to the longitudinal recess so that the adjustable shim is substantially located within a perimeter edge of the closure unit;
• configuring the adjustable shim in a generally compact configuration;
• positioning the closure unit in the rough opening;
• and
• displacing an elongated member on the adjustable shim in a first direction relative to the attachment member to deform the adjustable shim into an expanded configuration, the adjustable shim in the expanded configuration creating opposing forces simultaneously acting on the perimeter edge and the rough opening sufficient to suspend the closure unit in the rough opening.

An adjustable shim for positioning a closure unit in a rough opening, the closure unit including a frame with a perimeter edge and at least one longitudinal recess in the perimeter edge, the adjustable shim comprising:

• an attachment member releasably coupled with the longitudinal recess;
• at least one deformable leg having a first end and a second end coupled to the attachment member;
• and
• an elongated member coupled to the deformable leg in a compact configuration such that displacement of the elongated member relative to the attachment member in a first direction deforms the deformable leg into an expanded configuration, wherein the adjustable shim is substantially located within the perimeter edge in the expanded configuration.