Why Use Plastic Shims for Window Installations?

New construction and replacement windows are bulky and heavy, making them difficult to maneuver into place. Preventing them from shifting, ensuring they are level, and keeping them flush with the wall and frame would be enough to drive a contractor to distraction if it weren’t for plastic window installation shims. Specially designed to bear the weight of curtain walls, skylights, sloped glazing systems, plastic shims for window installation can easily be put into place to provide decades of smooth window operation.

Plastic window shims offer several advantages over those made of other materials.

Fire-resistance

Plastic shims for window installation often remain in place even after the windows have been positioned and installed. If a window is part of a building that must comply with non-combustibility construction codes based on its occupancies and functions, the shims, too, must be non-combustible. That precludes the use of wood shims in blast-resistant windows. It is essential that fire-rated plastic shims will not melt or maintain a flame, keeping windows safe and exits accessible during emergencies.

Adaptable

Often employed on large projects such as glass storefronts, where panels must be not only aligned with the frame but also properly spaced and aligned with each other, plastic horseshoe shims and U-shaped shims can be placed vertically as well as horizontally. Both are designed to fit around bolts and anchor screws, and both are robust enough to withstand as much as 10 tons of compressed force.

The Shimming Process

Plastic shims for window installation ensure the process is completed quickly and professionally. Plastic window shims should be used throughout the placement task:

1. Place plastic shims 14 to 16 inches apart under the sill to level the window horizontally.
2. Insert shims on both sides of the window near the top and bottom and at 20- to 24-inch intervals to position and straighten it vertically. Ensure the shims do not compress the frame.
3. The top of the window should remain unshimmed to allow it to move with the building’s settling and shifting without jeopardizing its operation.
4. After ensuring the window is plumb, level, and square and all locks, slides, and moveable parts work easily, anodized screws can be driven through the shims or nailing flange.
5. Excess shim material can be scored and broken off for finishing, aesthetics, thorough insulation, etc.

Choosing a Plastic Window Shim Manufacturer

Grove Shims produces solid American-made plastic shims from polypropylene, high-impact polystyrene, and ABS in a variety of common and industry-specific shapes. Request a quote now.