7 Things to Consider When Specifying Expansion Joints

There are a number of things to consider when specifying expansions joints, but before we get into the specifics, let’s review the details on why building joints are so important.

Why do we Need Building Joints?

A building can move in any direction—expanding, contracting, or sliding along the X and Y axis as well as up and down along the Z axis. Joints are needed to relieve this movement where there are long expanses and where the structure would crash into another fixed or independently moving structure.

What Type of Movement is the Building Subject to and How Much?
The type of movement a building is subject to impacts the joint. A standard expansion joint system allows for a range of motion of ±25 percent of the nominal joint width. For example, a 102-mm (4-in.) nominal expansion joint system will support a gap dimension of 76 to 127 mm (3 to 5 in.). An expansion joint specified to seismic standards supports movement of ±50 percent or, in this example, a gap of 51 to 152 mm (2 to 6 in.).

It is recommended that you form a close relationship with the structural engineer to be able to share ideas and ensure you are both on the same wavelength. It is also very important to remember that nominal joint size is slotted in the building and it expands and contracts from this size. However, you are designing to minimum and maximum sizes, so your joint needs to cover the worst case.

Joint Performance Considerations

Joint systems basically close off the gaps in a building system and still allow it to move while permitting persons to move about freely inside without tripping or slipping, and also maintaining the ability to carry the floor loads that have to be moved or rolled over it. The following are seven things to consider when specifying expansion joints from both an internal and external aspect. You should choose joints that:

  1. Minimize slipping or tripping hazards over the joint.
  2. Support necessary floor loads.
  3. Maintain fire separation integrity.
  4. Maintain sound separation integrity
  5. Maintain thermal separation integrity.
  6. Maintain moisture barrier integrity.
  7. Provide acceptable continuation of the finish.

In-depth Information About Building Movement

There are various types of building movements caused by the different forces to which a building is exposed. These forces, which have a bearing on joint integrity, include:

  • Thermal expansion and contraction caused by seasonal temperature changes
  • Moisture (rain/snow/humidity)
  • Sway caused by wind
  • Differential movement (seismic events, etc.)

Be assured that all these types of movements occur in every building and you should consider if the magnitude of the movement poses a threat to the structure or integrity of the finishes used to cover the structure?

Thermal Expansion and Contraction

This is a simple linear equation: Large temperature swings and expansive materials like steel and longer lengths create conditions for expansion and contraction. Understanding the thermal sensitivity and coefficient of expansion of the structural material is key to determining movement needs. Glass and wood generally have a lower coefficient of thermal expansion than metals. Question: Will your building be exposed to the full climatic range of temperature swing due to loss of power or off-hours energy conservation? If so, then the full climatic temperature swing should be calculated.

Moisture

Porous materials are prone to expansion (swell) and contraction (shrink) from moisture (rain, vapor, etc.). The swell and evaporation of water in building materials may impact the integrity of the structure over time. Freezing water inside structural components is of particular concern in colder climates as this causes significant strain on structural materials. Parking garages are examples of movement under sidewalks and drives.  They have considerable support structures beneath the surface. Moisture is mostly prevalent in gymnasium floors as architects will manage for moisture in all other applications. Wood fibers expand when wet—they get fatter, not longer. Wood expands in direct proportion to its moisture content. Different species of wood are more or less susceptible to expansion due to the varying structure of the grain. 500 inches of wood gym floor with an expansion coefficient of .0037 and a moisture change of 3% will expand 5.55 inches.

Wind

Wind on the face of a long expanse can cause the building to move perpendicular to the thermal expansion and contraction resulting in differential motion. Some joints are not capable of moving in two directions. (Use your hands flat to the ground to demonstration motion in two directions—side to side and towards and away from you.)

Remember it is important to take into account that all of these elements: heat, moisture and wind have an effect on the amount your building moves. Therefore, the kind of joints you specify will play a key role to helping minimize tripping hazards, provide support, maintain separation integrity for fire, sound, thermal and moisture barriers, and provide an acceptable continuation of the finish.  


Nystrom expansion joints are manufactured to solve a variety of expansion joint scenarios. Custom sizing, materials, and color finishes ensure that whatever you need for your project, we’ve got you covered. Our commercial building products are shipped direct from our central manufacturing facility or from one of our strategically located stocking locations, Nystrom delivers the expansion joints you need.


About Nystrom

Since 1948, Nystrom has been the go-to manufacturer of specialty building products offering a wide range of floor, roof, wall, ceiling and stair access products that create safer, more accessible buildings. Nystrom is also proud to offer hassle-free services like access to technical experts, REVIT tools for BIM, HPDs for LEED v43-part specifications and AIA continuing education courses.

Nystrom partners with BSD SpecLinkMasterSpec and BIMsmith for specification tools and are proud members of AIA, CSI, LBC, Sustainable Minds, HPDC and USGBC. Many Nystrom products meet the following standards: ADA, ASTM, Florida-Approved, FM Approved, IBC, IFC, Intertek Warnock Hersey, Miami-Dade Approved, NFPA, NYCBC, OSHA & UL.

Need help with your specification coordination?

We can help!

Hassel-Free Assistance

Every project is unique. Every location requires different building codes. And even though our products are well-made, and our services are hassle-free, we know we’re not a perfect fit for every project. However, we are a trusted resource that assist you on product selection, specifications, design build, HPD, code requirements and any other solution from small hiccups to big challenges.

Nystrom is proud to provide hassle-free building products serving divisions 05, 07, 08, 10 and 12 through 10 product lines. Our expert team of sales, service and engineers, valued partners and website can help with your specification coordination.

Architect Specifications

Specifications may seem like a no-brainer, but we want to highlight that Nystrom offers 3-part specifications in formats that work for you. You may download product specifications on our website or through our valued specification providers BSDspeclink and MasterSpec as well. You may view or download your selected file type from the following list of specifications:

• Access Doors
• Entrance Mats + Grills
• Expansion Joint Systems
• Fall Protection
• Fire Safety
• Floor Doors
• Luminous Egress Products
• Roof Hatches
• Smoke Vents
• Stair Treads + Nosings
• Wall + Door Protection

Design Build Resources

We understand that every construction project has a different level of complexity and challenge. That is why Nystrom often partners with project managers that require direct access to our people, products and process to ensure that their specific needs are addressed. No matter how complex or custom the product requirements are, our team will support a seamless project workflow. We offer service at every step from schematic to design and development to bid and procurement through construction and commissioning. Whatever information you need to complete your project is available on our website.

Technical Documents

Complete information and technical documentation is critical to your project. Information like CAD, Shop Drawings, Data Sheets and Warranty. All Design Build Resources are available on our website.

Revit/BIM Design Tools

We want to make your job easier by providing 3D tools for your projects. We have CAD resources for all products on our website. Nystrom also partners with BIMsmith for single source Revit/BIM content for the architecture community. Compare similar products to see their differences, then download your final selection for your Revit or AutoCAD projects quickly and easily.

Code Resources

Building codes vary from state to state and county to county and we know that it can be difficult to track how our products will fit in with your projects. Nystrom is happy to help you answer code questions as part of our hassle-free service. Some may be found on our website, or you can always reach out to our customer service team.

LEED & HPD

LEED has become the international standard for the design, construction and operation of high-performance structures. LEED v4 is designed to provide a more flexible, performance-based approach to calls for measurable results throughout a building’s lifecycle. If you have projects that require pursing LEED certification, Nystrom offers Health Product Declarations (HPD) to satisfy LEED v4 requirements. You may view or download your selected file type from the following list on our website.

Literature & Samples

While we’re living in a digital age, we know that hard copies of product information like catalogs and information sheets are still useful. Nystrom catalogs are available for digital download and printed catalogs may be ordered, both through the website. Product collateral and services may also be obtained through working with a regional partner with locations throughout North America.

Although our product images are of the highest quality, there is no substitute for seeing a product in person. We know you want to see, feel and touch to better understand our products. Of course, you care how it looks, but we know that you also care about its durability, how it performs and how it will look pared with other products. The Nystrom sample program can be accessed on our website.

Installations & Repair Made Easy

We know that videos are an ideal way of demonstrating the installation process. Nystrom not only provides Installation & Operation Manuals for all its products, but we provide video tutorials as well. Whether you’re working with a general contractor, project manager or specialty contractor, we are the go-to source for installation methods required for projects, regardless of the complexity.

Where applicable, videos can be accessed directly from the product information pages or through the Nystrom YouTube channel.

Project Profiles & Galleries

We know that providing a complete picture of projects if essential when specifying products. And, we understand seeing the finished project is not only appealing, but useful when specifying products. Nystrom provides project profiles and galleries for projects of all types.

Nystrom offers its design professional clients an in-depth array of information when it comes to architect specification assistance and design build resources.


About Nystrom

Since 1948, Nystrom has been the go-to manufacturer of specialty building products offering a wide range of floor, roof, wall, ceiling and stair access products that create safer, more accessible buildings. Nystrom is also proud to offer hassle-free services like access to technical experts, REVIT tools for BIM, HPDs for LEED v43-part specifications and AIA continuing education courses.

Nystrom partners with BSD SpecLinkMasterSpec and BIMsmith for specification tools and are proud members of AIA, CSI, LBC, Sustainable Minds, HPDC and USGBC. Many Nystrom products meet the following standards: ADA, ASTM, Florida-Approved, FM Approved, IBC, IFC, Intertek Warnock Hersey, Miami-Dade Approved, NFPA, NYCBC, OSHA & UL.

Specifying Fire Extinguisher Cabinets

6c8e95a9feefa98ae7cf295fb763In the event of a fire, a missing, empty or tampered fire extinguisher can lead to catastrophic loss. It is this reason that the installation of fire extinguisher cabinets is necessary. Fire extinguisher cabinets are designed to keep fire extinguishers, hoses and blankets secure while still providing accessibility in the event of a fire emergency. Although there are many options for fire extinguisher cabinets, we will cover the top three commercial uses.

Continue reading

3-Steps To Design Effective Joints

Picture1As a manufacturer of Expansion Joint Systems, we see a lot of mistakes on expansion joints that cause biding confusion and the inevitable change order. Some of the most common problems Continue reading