6 Best Galvanized Steel Shims For Leveling Base Plates

Leveling base plates is the foundation of a structurally sound installation, whether setting columns for a commercial steel frame or securing heavy machinery. When base plates sit unevenly on concrete foundations, the resulting stress concentrations can lead to bolt fatigue or structural failure over time. Galvanized steel shims provide the necessary support to distribute loads evenly across the grout or pad. Choosing the right shim is as critical as selecting the correct anchor bolt, as the wrong thickness or material will compromise the entire connection.

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Dayton Superior Slotted Shims: Best Overall

Dayton Superior shims are the industry standard for a reason: they combine precise manufacturing with a highly reliable galvanization process. These slotted shims allow for quick lateral insertion around anchor bolts without requiring the removal of nuts, saving significant time during the leveling phase.

The consistency of their thickness ensures that stack-ups remain predictable across large projects. If a job involves setting a multi-column steel mezzanine, these shims eliminate the guesswork often associated with varied plate tolerances.

Expect a clean, uniform edge that prevents snags during installation. When the schedule is tight and the structural inspector is on-site, having a reliable, ready-to-use shim is a major advantage.

Steel Supply L.P. Shims: Best for Custom Work

Not every structural project fits a standard catalog size. Steel Supply L.P. excels in scenarios where odd bolt patterns or oversized base plates require custom-engineered shim geometries.

When working on specialized retrofits where anchor bolt spacing is non-standard, custom-cut shims prevent the need for dangerous makeshift leveling methods. Their ability to produce specific dimensions means the shim fully covers the base plate footprint, which is vital for load distribution.

Precision in custom fabrication is non-negotiable when dealing with high-load structural steel. Always verify that the custom geometry matches the load-bearing requirements of the specific engineer-of-record design.

Precision Brand Steel Shims: Top Budget Option

Precision Brand offers a cost-effective solution for contractors who maintain a large inventory of shims for everyday light-duty projects. These shims provide the essential structural support required for leveling without the premium price tag of heavy-industrial specialty brands.

These are best utilized in high-volume settings where multiple base plates need minor adjustments. They are perfectly adequate for standard light-gauge steel framing or equipment mounting where the total load does not approach the upper limits of the steel’s yield strength.

While they may lack the heavy-duty finish of high-end options, they are entirely functional for most standard construction scenarios. Keep them organized by thickness in a gang box to ensure that no time is wasted scrounging for the correct size during installation.

G-Shim Tapered Shims: Easiest for Installation

Tapered shims are a lifesaver when the concrete foundation has a slight pitch or the base plate requires fine-tuned alignment. By rotating the shim or sliding it along the taper, the installer can achieve a level surface without swapping out multiple flat shims.

These shims significantly reduce the time spent on “trial and error” leveling. In scenarios where a floor slab is slightly out of plumb, a tapered shim provides a continuous bearing surface rather than a series of stacked, thin plates.

The primary benefit here is structural stability through surface contact. Avoid the common mistake of using multiple thin shims to compensate for a slope; a single, properly sized tapered shim is always more stable under load.

Meadow Burke Slotted Shims: Heavy-Duty Pick

Meadow Burke caters to the heavy construction market where load capacities are extreme and failure is not an option. These shims are manufactured from high-strength steel and feature robust galvanization that holds up under severe environmental conditions.

These are the go-to choice for heavy column base plates in industrial facilities or high-wind environments where uplift forces are significant. The rigidity of the metal ensures that it will not deform or compress under the immense pressure of heavy structural members.

Always check the load rating provided by the manufacturer before choosing a shim for high-impact or vibratory applications. Using an underrated shim under a heavy load will lead to early fatigue and potential shifting of the base plate.

Maass Midwest Shims: Unmatched Material Quality

Maass Midwest is known for rigorous quality control, ensuring that every shim in a batch is uniform in thickness and strength. In critical infrastructure projects, this consistency provides the engineer-of-record with the peace of mind that the leveling solution matches the structural calculations.

The galvanization coating on these shims is notably consistent, providing superior protection against oxidation in high-moisture climates. If a base plate installation is in a coastal region or a damp environment, the quality of the finish is the first line of defense against corrosion-induced loss of section.

Superior material quality translates to fewer callbacks and less maintenance. Paying a premium for documented steel quality is a smart investment when the project longevity depends on the integrity of the connection.

Slotted vs. Solid Shims: What Your Job Needs

Slotted shims are the efficiency choice for most site work, as they allow for installation around an existing anchor bolt. They minimize downtime, as the plate does not need to be completely removed or lifted excessively.

Solid shims are superior when the structural requirements demand a completely enclosed bearing surface for maximum load distribution. If the bolt pattern allows for the base plate to be set after the shims are placed, always opt for solid shims for a more stable, vibration-resistant mount.

Understand the tradeoffs regarding footprint. A slotted shim is convenient, but a solid shim provides a larger surface area to distribute the load into the grout.

Avoiding Shim Stack-Out & Other Common Errors

Stacking too many thin shims is one of the most dangerous errors in construction. This creates an unstable “layer cake” effect that can easily shift under structural vibrations or settlement, causing the entire column to lose plumb.

Aim to use the fewest number of shims possible to reach the desired height. If the stack exceeds three or four shims, it is time to use a thicker singular plate or a different leveling method, such as structural grout.

Always ensure the shims are placed directly under the vertical supports of the base plate. A shim sitting in the middle of a span without direct load is useless and can actually cause the base plate to bow or deflect.

Galvanized vs. Stainless vs. Plain Steel Shims

Galvanized steel is the standard for most outdoor and semi-protected structural applications. The zinc coating provides a sacrificial layer that prevents the base steel from rusting, which is essential when the shim will be embedded in or near concrete.

Stainless steel shims are mandatory in harsh, corrosive environments or when the base plate is constructed of high-grade stainless steel to prevent galvanic corrosion. Never mix dissimilar metals, as the chemical reaction can quickly degrade the shims and compromise the connection.

Plain steel shims should only be used in dry, climate-controlled interiors and must be protected by a high-quality sealant or grout. If the project is located in an area with high humidity or exposure to salt air, always default to hot-dipped galvanized or stainless steel.

Understanding Shim Load Ratings and Capacities

Load ratings are not merely suggestions; they are critical structural data points. Every shim has a yield strength that dictates how much pressure it can withstand before it deforms, which would cause the base plate to sag and the anchor bolts to lose tension.

Verify the shim material property against the weight of the structure being supported. A shim designed for residential framing will fail catastrophically if placed under the base plate of a heavy industrial crane or a large support beam.

Consult the structural engineer’s drawings to confirm the required shim thickness and material specifications. When in doubt, prioritize a higher load capacity rating; the cost difference is negligible compared to the cost of a structural failure.

Proper leveling with high-quality galvanized steel shims is the unseen anchor of a successful construction project. By choosing the right shim configuration and material for the specific environment and load requirements, the longevity and safety of the structure are significantly improved. Avoid the urge to cut corners with excessive stacking or improper material selection, and always prioritize the structural integrity of the base connection above convenience.