Why are Movement Joints Mandatory?

The Earth’s constant movement is an essential consideration in the building industry, as it directly affects the stability, safety, and longevity of structures. The Earth is constantly in motion due to several factors, and understanding these movements is crucial for architects, engineers, and construction professionals. Some of the key aspects related to the Earth’s movement and its impact on the building industry include rotation of the Earth, tectonic plate movement, earthquakes, subsidence, uplift climate-related movements, and sea level rise.  

Factors such as site selection, structural design, and building materials are all considered during the commercial construction process. To prevent materials from destructive failures, we must accommodate for movement. Take tile, for example. Ceramic and porcelain tile, by its very nature, is extremely dense and strong, making it an excellent choice for finished floor and wall coverings.  However, by the same token, it is not very flexible.  For this reason, movement joints are critical to the success and longevity of the tile assembly. Whether it’s thermal, shrinkage, freeze/thaw, or structural movement, tile and stone installations are constantly subjected to various types of conditions. Failing to incorporate movement joints into the installation will almost certainly guarantee cracks and tenting in the long run, leading to costly repairs or replacement. 

A movement joint, or expansion joint, is a deliberate separation or gap provided in a building or structure to accommodate the natural movement and deformation caused by various factors, such as temperature changes, settlement, seismic activity, or moisture variations. These joints allow different parts of the structure to move independently without causing damage or undue stress to the overall building. 

The primary purpose of movement joints is to prevent the formation of cracks, fractures, or distortion in the building components that can occur when materials expand or contract due to changes in environmental conditions or external forces. 

Whether residential or commercial, movements joints are mandatory; not voluntary.

Different Types of Movement Joints

In tile installation, movement joints are essential to accommodate the natural expansion, contraction, and shifting of materials due to temperature, moisture, and structural settling changes. Movement joints prevent the tiles from cracking or popping out of place. There are several types of movement joints used in tile installations:  

• Expansion Joints: These joints are designed to allow tiles to expand and contract without causing damage to the installation.  They are typically placed at regular intervals along walls, corners, and other fixed points. 
• Perimeter Joints: These joints are placed along the edges of the tiled area, such as where the tiles meet walls, cabinets, or fixtures. They help isolate the tiled surface from adjacent structures, preventing any direct contact that could lead to damage. 
• Contraction Joints: Like expansion joints, contraction joints allow for movement but are primarily used to accommodate the shrinking of materials. Particularly important in large tile installations to prevent buckling or warping of the surface.  
• Isolation Joints: Similar to perimeter joints, they are used to separate different sections of the tile installation. Focused on larger areas to divide the surface into manageable sections.  
• Control Joints: These are pre-planned cracks or grooves cut into the tile surface, as they are intended to control where the tiles may crack or shift. This provides a weak point to guide the movement and prevent random cracking.  
• Movement Joint Strips: A prefabricated flexible strip made of materials like PVC or rubber, which are installed at specified intervals and embedded into the tile adhesive or mortar. They offer a predictable way to accommodate movement.  
• Caulk Joints: These joints are filled with a flexible sealant, such as silicone, and are commonly used at changes of plane, where walls meet floors and around fixtures. This method provides a waterproof seal, allowing for slight movement.

The exact type and placement of movement joints can vary depending on factors like tile size, material, substrate, environmental conditions, and project specifications. Following the industry standards and manufacturer’s recommendations is crucial to ensure a durable and long-lasting tile installation. A qualified tile installer or professional in the field can help determine the appropriate type of spacing of movement joints for a specific project. 

Expansion Joint

The importance of an expansion joint in tile installation cannot be overstated. By incorporating expansion joints, tile installers can ensure a stable, durable, and aesthetically pleasing surface that stands the test of time. The diagram below considers this an expansion joint due to the full-depth assembly.

The Tile Council of North America (TCNA) provides general movement joint guidelines for tile and stone applications.  This section is called EJ171 Movement Joint Guidelines for Ceramic, Glass, and Stone.

The general rule for placing movement joints in ceramic tile and stone installations is to have an expansion joint every 8 to 12 feet in each direction, with additional joints at all perimeters, changes in plane, and transitions to other surfaces. 

This general rule accommodates the natural expansion and contraction of ceramic tile and stone materials due to temperature changes and other external forces. Properly placed movement joints help prevent the occurrence of cracks and other issues that may arise from the differential movement of the materials. 

It‘s important to note that specific installation requirements and guidelines may be subject to updates and revisions over time. For the most current and accurate information regarding movement joint requirements for ceramic tile and stone installations, it is recommended to refer directly to the latest version of TCNA’s EJ171 publication or consult with a qualified tile installation professional. 

Perimeter Joint

The perimeter joint, also known as the perimeter gap or edge joint, plays a significant role in tile installation. It refers to the space left between the tiles and surrounding elements where the tile is installed. The diagram below represents the view of a perimeter joint.

TCNA EJ171G-11 states that perimeter joints are essential to accommodate building movements and prohibit cracks in the substrate from telegraphing to the tile finish. This detail illustrates a perimeter expansion joint where the tile floor terminates into an inside corner of the tile walls.

Section EJ171G-11 also states that all underlying movement joints in the substrate must continue through the tile assembly. This means that tile installation requires additional movement joints in conjunction with honoring the substrate movement joints. If there is a mortar bed over the substrate, then the movement joint must be continuous through it to the tile surface, which is considered an expansion joint. If the tile is being bonded directly to the substrate, and there is no substrate movement joint continuing up from beneath, it is called a generic movement joint. 

Movement joint recommendations for food service, corporate workplace, hospitality, and multi-family projects are crucial to ensure the integrity and longevity of these installations. Here are some key considerations and recommendations for incorporating movement joints in commercial installations: 

• Type of Material: Materials such as ceramic tiles, stone, or fiberglass, have different coefficients of thermal expansion. It’s essential to account for these variations when designing movement joint placement. 
• Expansion and Contraction: Temperature fluctuations and moisture exposure can cause materials to expand and contract. Movement joints must be strategically placed to allow for these changes without causing stress and damage to the surrounding structures. 
• Perimeter Joints: In hospitality, multi-family and other projects, bathtubs and showers should have movement joints around their perimeter. These joints should be placed between the edge of the fixture and the surrounding walls or floor to accommodate any movement. 
• Changes in Plane: For different planes, such as wall or floor transitions, movement joints should be incorporated to prevent cracking at these junctions. 
• Control Joints: Control joints are designed to help control cracking in large surface areas. For large commercial showers or multiple shower stalls in a row, control joints may be necessary to manage the potential for cracks due to thermal expansion. 
• Manufacturer Recommendations: Follow the manufacturer’s recommendations and guidelines for movement joint placement in the specific bathtub or shower installation. Different products may have varying requirements based on their design and materials. 
• Adhesive and Grout Selection: Use flexible adhesive and grout materials that can accommodate slight movements without cracking. Consult with the manufacturer for appropriate product choices. 
• Expansion Joint Covers: In commercial settings, where heavy foot traffic or frequent cleaning may be expected, consider using expansion joint covers to protect and maintain the integrity of the joints. 
• Regular Inspections: Perform regular inspections of the movement joints to identify any signs of damage or wear. Address any issues promptly to prevent further damage. 
• Consult with Professionals: For commercial building projects, it’s essential to work with experienced architects, engineers, and tile installation specialists who are familiar with the specific movement joint requirements and can ensure compliance with industry standards. 

By following these movement joint recommendations, commercial buildings can maintain durability, enhancing the overall safety and aesthetics of the facility. 

To ensure a long and successful installation, strategically incorporating movement joints and using the proper types of sealants are a must – not an afterthought. (If you’re familiar with past Tile Talk Blogs, you’re likely familiar with Mapei.)

As always, for tile technical assistance. contact any member of the QA&T Team. Your success equals our success.