Material is often the first thing to consider. Plastic shims are a strong option when you want moisture resistance and long-term stability, since products like Glazelock tapered shims are waterproof and resist splitting, shrinking, warping, and rot. Wood shims remain a common choice for general carpentry tasks such as doors, windows, trim, cabinets, countertops, and flooring. Cedar shims can also be useful when you need a wood product that handles temperature and moisture variation well. Troxell horseshoe shims serve jobs that need hard plastic with minimal compression.