Have you ever wondered how tall buildings remain stable and strong despite natural disasters such as earthquakes and high winds? The answer lies in the building’s foundation and structure, which are supported by shims. Shims are thin pieces of material used to fill gaps between two surfaces, providing stability and support. 

In this blog post, we will explain the basics of shimming in construction, including what shims are, their importance in building structures, different shapes and sizes of shims, materials used for shims such as wood and steel, essential tools needed when working with shims, tips for efficient usage, troubleshooting installation issues, best practices in the construction industry when using shims and whether or not they can make a significant difference in building stability. Keep reading to learn more about this crucial aspect of construction!

Understanding Shims in Construction

Shims are vital tools in construction, serving to level, align, and support structures. They compensate for material inconsistencies, resulting in a stable foundation. Shims can be made of wood or steel, depending on construction requirements. Their versatility allows for precise adjustments during the building process, offering a cost-effective solution for leveling and alignment.

Defining Shims

Shims, being thin and wedge-shaped materials, are commonly used in construction to fill gaps and provide support. They come in various thicknesses, allowing for precise adjustments in leveling and alignment. Shims can be made of wood, plastic, or metal, depending on the desired strength and durability. By preventing uneven settling, shims contribute to stability and structural integrity in foundation construction, carpentry, masonry, and other building applications.

Importance of Shims in Building Structures

Shims are essential for achieving level and plumb construction, ensuring stability and safety. They distribute the load evenly, minimizing stress on the foundation and structure. Proper installation prevents moisture penetration, reducing the risk of rot, rust, and corrosion. Shims also allow for adjustments, compensating for imperfections in building materials. Their use ensures compliance with building codes and enhances construction quality.

Different Shapes and Sizes of Shims

Shims come in various shapes, such as wedge, tapered, and rectangular, catering to specific construction needs. Different shim sizes accommodate varying gap widths, providing precise leveling and alignment. Tapered shims are ideal for leveling, while wedge shims offer stability and support. Rectangular shims are versatile, suitable for leveling, spacing, and aligning construction components. Shims with precision measurements ensure accurate leveling, minimizing construction errors.

Materials Used in Shims: Wood and Steel

Wood shims, with their excellent load-bearing capacity and ease of installation, are a popular choice for construction projects. On the other hand, steel shims offer high strength, durability, and corrosion resistance, making them ideal for heavy-duty applications. Choosing between wood and steel shims depends on factors such as construction requirements, load capacity, and environmental conditions. Both materials provide reliable support and stability in building structures.

Characteristics of Wooden Shims

Wooden shims, made of durable cedar, offer good load-bearing capacity. They can be easily adjusted, trimmed, or stacked for desired leveling or spacing. With good moisture resistance, wooden shims reduce the risk of rot, corrosion, and foundation damage. Cedar shims, in particular, have natural resistance to insects, fungi, and moisture, enhancing their longevity. Cost-effective and readily available, wood shims are suitable for various construction applications.

Advantages of Steel Shims

Steel shims offer exceptional strength, stability, and load-bearing capacity, making them ideal for heavy construction. With excellent durability and corrosion resistance, steel shims can withstand harsh environmental conditions. Their consistent thickness ensures accurate leveling and alignment, while their reusability reduces construction waste and provides long-term cost savings. The high precision of steel shims minimizes compression, ensuring level and plumb construction.

Comparing Wooden and Steel Shims

Wooden shims are cost-effective for construction, while steel shims offer superior strength and durability. Wood shims are easy to cut and shape, while steel shims provide precise thickness measurements. Choosing between wood and steel shims depends on construction requirements, load capacity, and budget. Wooden shims work well for lighter construction, while steel shims excel in heavy-duty applications. Wood shims may require maintenance, whereas steel shims have a longer lifespan with less maintenance.

Manufacturing Process of Shims

Wooden shims are made by cutting, shaping, and sanding cedar wood planks into wedge-shaped pieces. Cedar is known for its durability and moisture resistance. Steel shims, on the other hand, are made through precision cutting, shaping, and finishing with machinery to create durable and reliable products. Both wood and steel shims meet industry standards for construction applications.

How Wooden Shims are Made

To make wooden shims, high-quality cedar wood planks are selected. These planks are cut into various thicknesses, typically ranging from 1/16 inch to 1 inch. The wood pieces are then shaped into wedge-like shims, tapering towards one end for easy installation. After shaping, the shims undergo sanding to achieve smooth surfaces, ensuring proper leveling and alignment. Finally, the wooden shims are inspected for quality, packaged, and made available for use in construction projects.

How Steel Shims are Produced

Steel shims are produced through precision cutting and shaping of high-quality steel using advanced machinery and laser cutting technology. This production process ensures accurate dimensions and durability. Steel shims are designed to withstand high compression loads, making them the best shims for construction applications. Quality control measures are implemented to ensure precision and reliability.

Practical Application of Shims in Construction

Shims are commonly used in construction for leveling and aligning doors, windows, and cabinets. They also level subflooring, provide a sturdy foundation for flooring, and level concrete blocks or stones. Woodworking uses shims to adjust workpiece height for precision. Shims are even used in automotive repair to optimize performance. Their versatility makes them valuable across construction disciplines.

Where to Use Shims

Shims serve various purposes in construction. In residential construction, they level and plumb wall studs for structural integrity. In concrete construction, shims level foundation walls, anchor bolts, and sill plates. HVAC installations use shims to stabilize air conditioning units, ductwork, and ventilation grilles. Shims also ensure stability in furniture assembly and maintain consistent grout lines and level tiles during tile installation. Their versatility makes them indispensable for providing stability and precision in construction projects.

How to Install Shims Effectively

To effectively install shims, start by identifying high spots or gaps that require shimming. Strategically place shims, distributing them evenly to ensure consistent pressure distribution. Properly seat the shims to provide a stable foundation or level surface. For wood-to-wood applications, use wood shims, while plastic shims are suitable for other materials due to their moisture resistance. Finally, test the stability of the shimmed area by applying pressure or performing a level check.

Tools Required for Shim Installation

To achieve precise leveling, you’ll need essential tools for shim installation. These include a level, masonry chisel, pliers, and mallet. For larger surfaces or longer distances, a laser level can provide greater accuracy. Shims can be installed with wood glue, construction adhesive, or mortar depending on the application. Use a plate level or spacer to help with leveling and aligning shims during installation. Prioritize safety by wearing gloves and safety glasses when handling shims and tools.

Essential Tools for Working with Shims

To accurately place shims, you need a level to determine surface levelness. In masonry construction, a masonry chisel is used to create space for shims by removing excess mortar. Pliers are helpful for precise placement and adjustment of shims in tight spaces. A mallet can be used to tap shims into place for stability and compression. For precise leveling and alignment of shims, a plate level or laser level can assist.

Safety Measures When Using These Tools

Prioritize safety when working with shims and tools. Wear the necessary personal protective equipment, follow manufacturer guidelines, and keep your work area clean and organized. Exercise caution when handling sharp tools to avoid injuries. Secure workpieces properly to prevent accidents.

Common Problems in Shim Installation and Their Solutions

To prevent splintering or cracking of wood shims during installation, use high-quality, durable shims like cedar and avoid excessive force. Check shimmed areas periodically for even leveling and readjust or replace shims as necessary. Use moisture-resistant shims and ensure proper moisture barrier installation to prevent rot. For large or heavy objects, consider using additional shims or alternative leveling methods.

Troubleshooting Shim Installation Issues

To troubleshoot shim installation issues:

  • If the shims are difficult to insert, widen the gap with a chisel.
  • Reduce the thickness of thick shims using sandpaper or a chisel.
  • Use precision shims of different thicknesses for uneven leveling.
  • Consider alternative leveling methods like grout, mortar, or adjustable feet.
  • Reinforce splintered or cracked shims with glue or construction adhesive.

Expert Tips for Efficient Shim Usage

To ensure a snug fit and stable support, prioritize precision when selecting shims. Optimize efficiency by using shims only when necessary and exploring alternative methods for leveling or alignment in specific applications. Regularly inspect shimmed areas for compression, shifting, or moisture damage. Consult construction professionals or experienced woodworkers for complex projects. Stay updated on new shimming technologies and best practices through industry resources to enhance knowledge and expertise.

Shimming Best Practices in the Construction Industry

Proper shimming is crucial in construction to ensure level, stable, and durable structures. It compensates for uneven surfaces and facilitates accurate installation. Using high-quality shims, such as wood or plastic, is essential. Install these shims at key contact points for optimal support, like between joists and sill plates. By following best shimming practices, you can prevent structural issues, moisture penetration, and other problems.

Can Shimming Make a Significant Difference in Building Stability?

Shimming plays a crucial role in building stability by distributing weight evenly and ensuring proper installation of fixtures. It compensates for variations in materials and foundation settling, resulting in a level and durable structure. Without proper shimming, buildings may experience structural issues and compromised integrity.


In conclusion, shims play a crucial role in the construction industry by providing stability and leveling support to building structures. Whether you choose wooden shims or steel shims, each material has its own advantages and characteristics that make them suitable for specific applications. Understanding the manufacturing process and knowing how to install shims effectively is essential for achieving the desired results. 

Additionally, using the right tools and following safety measures ensures a smooth installation process. While shimming can solve many common problems in construction, it is important to be aware of troubleshooting techniques and expert tips for efficient usage. If you have any questions or need further assistance with shimming in your construction projects, feel free to get in touch with us.