Plastic or wood shims: which should you use for a door, window, or cabinet installation? Neither material is automatically best for every job. Compare moisture exposure, shim shape, required thickness, and the installation manufacturer's instructions. Glazelock® offers both plastic and natural pine wood shims, so you can choose a product suited to the task rather than relying on a blanket material claim.
For product types and additional guidance, visit the Glazelock resource hub.
Plastic vs. Wood Shims: The Main Differences
Plastic shims: Glazelock's WL02 Wedgelock and GL-H8 tapered wedge listings describe plastic that will not rot, compress, or absorb moisture. These are useful features to consider where moisture exposure matters. They are product-specific descriptions, not a published load rating for every plastic shim or every installation.
Wood shims: Glazelock's natural pine shims are tapered wedges listed for window, interior and exterior door, cabinet, and general construction leveling. They can be cut, scored, or snapped to length. Wood is not limited to temporary leveling; use it where the installation requirements allow it.
Moisture exposure is an important selection factor for wood. However, this comparison does not establish a fixed rot timeline, a universal strength advantage for plastic, or a guarantee that either material prevents an installation from moving.
Choose the Shim Shape as Well as the Material
- Tapered wedges: Provide thickness adjustment along the taper. Both pine and plastic wedge options are available.
- Horseshoe shims: Have a slot that can fit around compatible bolts, pipes, or hardware. Check the specific slot width and footprint.
- Interlocking shims: Selected Glazelock models lock together when stacked to help prevent shifting during installation. This feature does not apply to every Glazelock shim.
- Snap-off stackable shims: Selected models have sections that can be broken off to adjust length and can be stacked for thickness control.
Current Glazelock Product Examples
- Natural pine wood shims: 8 inches × 1-1/4 inches × 3/8 inch; tapered wedge profile. Original and pre-scored options are listed, so confirm the selected variant and pack quantity.
- WL02 Wedgelock plastic shims: 8 inches × 1-1/2 inches × 5/16 inch; black plastic tapered wedges; 288 shims per box.
- GL-H8 plastic tapered wedge shims: 1-1/2 inches × 7-3/4 inches; black plastic. Check the selected packaging option.
- Heavy-duty interlocking U shims: 4 inches × 3 inches with a 7/8-inch slot; heavy-duty plastic with an interlocking stacking design.
The current Shopify listings for these four products identify them as Made in USA. Dimensions, thicknesses, and quantities vary by product and selected option; do not assume one pack size or specification applies across the range.
Choosing Shims for Doors, Windows, and Cabinets
- Follow the door, window, cabinet, or assembly manufacturer's requirements for shim material, placement, support, and fastening.
- Check moisture exposure and select a shim approved for the installation conditions.
- Match the footprint, thickness, taper, and slot size to the gap and supporting surface.
- Use interlocking or snap-off features only as described for the selected model.
- Check alignment and operation during fastening. Do not use this material comparison as a substitute for a specified support layout or load rating.
The reviewed listings do not establish a universal instruction to nail or screw through every plastic shim without cracking. Confirm the selected product's fastening guidance before drilling, nailing, or screwing through it. A moisture-resistant shim also does not replace required flashing, sealants, or drainage details.
Frequently Asked Questions
Are plastic shims better than wood shims for moisture-prone installations?
Moisture resistance is a reason to consider plastic. Glazelock's WL02 and GL-H8 listings describe plastic that will not rot or absorb moisture. The correct choice still depends on the assembly manufacturer's installation requirements.
Can wood shims be used for permanent door and window installations?
Yes. Glazelock lists its natural pine wood shims for window, interior and exterior door, cabinet, and general construction installations. Follow the requirements for the specific project rather than treating wood as temporary-only.
Are all Glazelock shims interlocking?
No. Glazelock offers multiple designs. Its heavy-duty interlocking U shims lock together when stacked; do not assume tapered wedges or other models have that feature.
Can you nail or screw through plastic shims?
Check the instructions for the specific shim and assembly. The reviewed listings do not establish that every Glazelock plastic shim can be nailed or screwed through without cracking.
Are plastic shims stronger than wood shims?
The reviewed listings do not provide a controlled plastic-versus-wood strength comparison. Choose by the required support, product dimensions, and installation specifications rather than assuming a universal strength ranking.
Are Glazelock plastic and wood shims Made in USA?
The current listings for the natural pine wood shims, WL02 Wedgelock plastic shims, GL-H8 plastic wedges, and heavy-duty interlocking U shims identify them as Made in USA.
Find the Right Glazelock Shim
Shop Glazelock shims to compare product shapes and available options, or use the Glazelock guide and resources for more information. You can also browse the FLI Products resource hub.
