6 Best Steel Shims For High Load Bearing Professionals Use
Discover the 6 best steel shims engineered for high load-bearing professional applications. Improve your structural alignment and read our expert guide today.
Structural integrity relies on the hidden details that bridge the gap between heavy steel beams and uneven foundations. When a column base sits a fraction of an inch off-plane, the entire load path becomes compromised, leading to structural settling or failure. Selecting the correct steel shim is not merely about filling a void; it is about maintaining a rigid connection that handles thousands of pounds of downward pressure. Professionals understand that the difference between a secure assembly and a potential liability often comes down to the quality of the metal buried beneath the grout.
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Dayton Superior Slotted Steel Shims: Best Overall
These slotted shims are the industry standard for a reason. They provide a predictable, high-strength solution that slides easily around anchor bolts, saving time during the critical leveling phase of a column set.
Consistency is the primary advantage here. Because these are manufactured to precise tolerances, installers can predict the exact stack height without relying on guesswork. When leveling heavy steel beams, this reliability prevents the need to redo a leveling operation once the structural load is applied.
The open slot design allows for installation after the bolt is set, which is vital when working on rapid-turnaround commercial sites. It simplifies the alignment process when the anchor bolts have drifted slightly during the concrete pour. Stick with these if the priority is speed and verified structural compliance.
Maectro Solid Carbon Steel Shims: For Max Loads
When dealing with massive structural loads where compression resistance is non-negotiable, solid steel is the only choice. These shims offer a high-density profile that resists deformation under extreme weight, ensuring that the gap remains constant over the life of the structure.
Unlike thinner, stamped alternatives, these solid steel shims won’t “nest” or compress under heavy vibration. They are ideal for base plate leveling on heavy machinery or multi-story structural columns where the load per square inch is significant. Their rigidity provides a stable platform that prevents point-loading on the grout.
One tradeoff is the lack of a slot; the bolt must pass through a pre-punched hole or be placed before the shim. This requires more foresight during the layout phase, but the trade-off in structural stability is absolute. Use these where failure is not an option.
Steel Supply L.P. Tapered Wedges: For Alignment
Tapered wedges are the go-to tool for fine-tuning the pitch of a steel member during the installation phase. When a beam requires a minute adjustment in height, a tapered wedge allows for infinite, incremental shifts that a flat shim simply cannot provide.
Use these for precision alignment on projects where structural members must be perfectly plumb. Because they provide a continuous contact surface as they are driven into place, they create a much more stable interface than stacking multiple flat, thin shims.
Be aware that wedges have a smaller surface area in contact with the flange compared to a flat shim. Always pair them with a proper non-shrink grout after the final elevation is set. This locks the wedge in place and ensures full bearing contact.
G-Shim Pre-Cut Horseshoe Shims: For Bolt Paths
Horseshoe shims are designed for speed and convenience in light to medium-duty applications. Their unique geometry allows them to be inserted into tight gaps without removing hardware, which is a lifesaver when fixing a level issue discovered late in the build.
The color-coded plastic variants are popular, but the steel versions offer the durability needed for heavy-duty construction. If the project involves securing steel-to-steel connections in high-wind zones, the steel horseshoe shim is the only version that will hold its shape under load.
Avoid the temptation to stack these too high. The more individual shims in a stack, the higher the risk of lateral shifting. Limit any single shim stack to three pieces total to maintain structural stability.
Fastenal 304 Stainless Shims: For Wet Areas
Corrosion is the silent enemy of any exterior structural connection. In high-moisture environments, such as exposed steel pergolas or coastal metal framing, standard carbon steel will rust, eventually expanding and blowing out the grout or cracking the concrete.
304 stainless steel offers the necessary resistance to oxidation while maintaining the strength required for load-bearing. This is the specification of choice for any connection that stays below the grade or is exposed to the elements.
Remember that stainless steel has a different hardness profile than mild carbon steel. When torquing down bolts over these shims, ensure that the connection is checked for potential galling—where the metal threads fuse under pressure—by using a high-quality anti-seize lubricant.
Precision Brand Shim Stock: Best for Custom Jobs
Sometimes the gap isn’t uniform, and an off-the-shelf shim just won’t fit the specific geometry of the project. Precision Brand shim stock allows contractors to cut custom lengths and widths, ensuring a perfect fit for irregular base plates or shim-heavy site adjustments.
These rolls come in varying thicknesses, allowing the installer to build a custom shim that is exactly what the structural engineer specified. It eliminates the “too thick or too thin” dilemma often encountered with standard, pre-punched shims.
Use these for critical field modifications where the plan doesn’t match the reality of the site. Keep a variety of thicknesses in the truck, as it is far easier to trim a custom shim on-site than to wait for an order of specialty parts.
Carbon vs. Stainless Steel: Which Shim to Use?
The choice between carbon and stainless steel is driven by the environment rather than just the load. Carbon steel is stronger and more cost-effective for indoor, climate-controlled environments where moisture is not a factor.
Stainless steel is non-negotiable in wet or corrosive climates. Using carbon steel in a high-moisture zone invites galvanic reaction and oxidation that will degrade the integrity of the base plate connection over time.
Always match the shim material to the base plate and the anchor bolt material. If the steel beam is hot-dipped galvanized, stick to compatible materials or galvanized shims to prevent long-term issues.
Slotted Horseshoe or Solid: Pick the Right Type
Slotted shims are the workhorse for speed, but they possess a minor structural weakness: the open end can potentially spread under extreme tension if not properly confined by grout. Solid shims, by contrast, offer a uniform bearing surface that is superior for heavy-duty columns.
Horseshoe shims are for fine-tuning and adjustments. They are perfect for small corrections, but they should never be the primary bearing element in a high-load, multi-story structural column.
Assess the load profile before choosing. If the beam is static and the load is light, a slotted or horseshoe shim is fine. If the member is a primary load-bearing column, prioritize a solid shim with a closed hole.
Calculating Your Shim Stack for Proper Support
Never “stack to fit” without a plan. An excessive number of individual shims creates a unstable “sandwich” that can shift under wind loads or vibration, potentially throwing the entire beam out of plumb.
As a rule of thumb, limit the total number of shims in any single stack to three or fewer. If the gap requires more than this, switch to a thicker single shim or use a high-strength steel plate that matches the footprint of the base plate.
Always confirm that the shim stack is fully enclosed within the perimeter of the base plate. Shims that protrude past the base plate create a trip hazard and are more susceptible to bending under load.
Avoiding Galvanic Corrosion With Dissimilar Metals
Galvanic corrosion occurs when two different metals are in contact in the presence of an electrolyte, like rainwater. This creates a small electrical current that eats away at the less noble metal, compromising the structural bond.
When choosing shims, always match them to the structural members they contact. A stainless steel shim against a carbon steel base plate is generally acceptable, but a copper or aluminum component against a carbon steel beam will lead to rapid degradation.
If you must mix materials, use a dielectric barrier or a high-quality, corrosion-resistant coating on the shims. Proper planning at the specification stage saves the client from expensive remediation a decade down the line.
Selecting the right shim is a matter of respecting the load path and planning for the environment. By choosing material thickness and composition with care, you ensure the structure remains as rigid and secure as the day it was built.
