7 Best Roofing Wedges For Temporary Support Pros Use

When a framing member is slightly off-square or a metal roof panel needs a precise lift to clear an obstruction, the right shim is the difference between a professional finish and a structural headache. Relying on makeshift debris or incorrect materials creates high-pressure points that lead to cracked substrates or compromised fasteners. Choosing the correct wedge ensures load distribution remains stable under the weight of heavy decking or solar arrays. Master the use of these temporary support tools to maintain the structural integrity of every roofing system.

Disclosure: As an Amazon Associate, this site earns from qualifying purchases. Thank you!

Wobble Wedges Flexible Plastic Shims: Best Overall

Wobble Wedges are the gold standard for versatility because their tapered, textured design allows for fine-tuned adjustments that wood simply cannot match. The flexible plastic material compresses slightly under heavy loads, which helps absorb minor vibrations and prevents the shim from slipping out of place during installation.

These are essential when dealing with uneven substrate or when a metal roofing panel needs to be leveled over a slightly bowed rafter. The variety of thicknesses ensures that small gaps—often measured in sixteenths of an inch—can be closed without over-lifting the material.

Because they are made from high-density plastic, they resist moisture and will not rot if trapped beneath a roofing layer. Keep a multi-pack on hand, as they are ideal for leveling drip edge or stabilizing flashing that requires a tight, non-corrosive fit.

Nelson Wood Shims: The Classic Contractor Standard

Nelson wood shims remain the go-to for traditional framing and instances where a firm, non-compressible support is required. These are typically cut from cedar or pine, making them easy to trim with a standard utility knife or a set of snips once they are tapped into the final position.

When shimming rafters for a level deck on a heritage building restoration, the natural grain of wood provides a predictable compression rate. This allows for a “crush-fit” that locks the shim into the gap, creating a static, immovable connection that holds tight under the weight of plywood or OSB sheets.

The bottom line is that wood shims are cost-effective and easy to modify on the fly. Just ensure they are kept dry until the moment of installation, as moisture-swollen wood can distort the very level lines one is trying to achieve.

EZ-Shim Heavy Duty Shims: Best for Structural Lifts

EZ-Shim products are specifically engineered for heavy-duty applications where standard shims might collapse under the weight of multiple roof layers. Their composite construction is designed to bear significant point loads, making them suitable for shimming heavy structural beams or ridge boards.

In scenarios where a heavy-duty lift is required to correct a sagging ridge, these provide the necessary stability without the risk of splintering. They are rigid enough to maintain their shape under the pressure of a hydraulic jack or a long-arm pry bar, which is essential for accurate alignment.

While they cost more than basic cedar shims, the investment is justified when structural safety is on the line. Use them when the project demands precision under heavy, localized pressure that would otherwise crush softer materials.

Go-Wedge Plastic Wedges: Top Choice for Durability

Go-Wedges offer high-impact resistance and a shape that is optimized for aggressive prying and positioning. Their structural integrity makes them a favorite for roofers who need a tool that doubles as both a leveler and a temporary wedge during the installation of heavy metal panels.

They perform exceptionally well in extreme temperatures, resisting the brittleness that often plagues lower-quality plastics during cold-weather roofing. The textured surface provides excellent friction against both wood decking and metal surfaces, ensuring that once it is placed, it stays.

These are the right choice when the job site is rough and the wedges will be exposed to repeated striking or heavy loads. They are virtually indestructible in a standard construction environment, making them a long-term asset in any tool belt.

Big Foot Shims: Best Interlocking Plastic System

The Big Foot system is unique because it features an interlocking design that allows multiple wedges to be snapped together to create a larger, more stable base. This is particularly useful when shimming a wide gap where a single, thin wedge would be unstable and prone to tipping.

If you are working on a commercial flat roof and need to shim a rooftop unit or a heavy HVAC curb, these provide a secure, wide footprint that distributes weight effectively. The ability to stack and lock ensures the shim stack won’t shift during the fastening process.

By using this system, the risk of “shim creep”—where wedges vibrate out of place—is significantly reduced. It is an ideal solution for any roofing professional prioritizing long-term structural stability over quick, temporary fixes.

CEP Wood Cribbing Blocks: For Heavy-Duty Jacking

CEP blocks are not traditional wedges, but they are the pro’s choice for heavy-duty jacking operations on large-scale roof projects. When a section of roof deck needs to be raised to repair a structural member, these blocks serve as the foundation for the jack.

Their engineered design allows for safe, incremental stacking, providing a secure platform that prevents jack slippage. Using improvised scrap wood for heavy jacking is a recipe for disaster; these purpose-built blocks are rated for high-stress loads.

Always use these when working on large-span residential or commercial roofs where hydraulic jacks are necessary. They simplify the process of establishing a stable, level base on uneven ground or sloped surfaces.

Site-Cut Lumber: The Pro’s Go-To Custom Wedge

There is no substitute for a wedge cut on the saw from high-quality 2×4 or 4×4 stock when dealing with odd-sized, wide-span gaps. A custom-cut cedar or pressure-treated wedge can be shaped to fit the exact geometry of an irregular roof hip or valley.

When cutting these on-site, match the taper to the specific pitch of the roof to ensure the load is carried across the entire surface of the wedge. This maximizes surface contact and prevents the “teeter-totter” effect that occurs when a wedge doesn’t fit the slope correctly.

• Always treat cut ends with a wood preservative to prevent rot.
• Avoid using scrap OSB or plywood for wedges, as they delaminate under pressure.
• Prioritize rot-resistant species like cedar or redwood for any permanent shim applications.

Wood vs. Plastic Wedges: Which Is Right for the Job?

The choice between wood and plastic ultimately depends on the environment and the load-bearing requirements of the project. Plastic is the clear winner for moisture-heavy environments or areas where the shim will remain permanently exposed to the elements.

Wood remains superior for situations requiring a custom fit or where high friction is necessary to prevent slipping. Because wood has a slightly softer surface, it often conforms better to rough-sawn lumber rafters found in older roofing systems.

• Plastic: Best for leveling drip edge, metal panels, and HVAC curbs.
• Wood: Best for framing adjustments, ridge alignment, and custom-cut applications.

Safety First: Load Ratings and Proper Wedge Use

Never exceed the load-bearing capacity of a plastic wedge when using it as a structural component. Always consider the total weight of the roofing materials—including the weight of the crew—when determining how many shims to use and where to place them.

Proper shim placement requires that the wedge is positioned directly under the structural member, not just under the sheathing. Placing a shim under a piece of plywood without rafter support will inevitably lead to a soft spot in the roof, which can cause damage to the shingles or underlayment over time.

Inspect all shims during the final walk-through. A wedge that is loose or poorly seated acts as a point of failure that can cause ripples in a flat roof membrane or uneven lines in a metal panel installation.

Pro Tips for Jacking and Shimming on the Jobsite

Always use shims in pairs whenever possible, sliding two wedges against each other in opposite directions to create a flat, parallel surface. This simple technique ensures that the load is distributed evenly across the shim rather than at a single, concentrated point.

If you are jacking a roof to correct a bow, do so in small, measured increments. Rushing the process can cause the structure to crack, particularly in older buildings where the framing has already settled into a new, albeit incorrect, position.

Finally, keep a bucket of assorted wedges in the truck at all times. The cost of a few plastic wedges is pennies compared to the time lost tracking down a level surface when the job is already underway.

Selecting the right wedge is about more than just filling a gap; it is about ensuring the long-term structural health of the roofing system. By matching the material and design of the shim to the specific challenges of the site, professionals can ensure that every job meets the highest standards of quality and durability.