How Are Expansion Joints Installed in Flooring?

Expansion joints are an essential component of any extensive flooring system — particularly in commercial, industrial, or outdoor environments. Without them, flooring material will crack, buckle, or warp as a result of temperature fluctuations, structural movement, or moisture variation.

What Are Expansion Joints?

An expansion joint is a regulated opening inserted between two flooring or structural sections. It provides for:

Thermal expansion and contraction
Absorption of vibrations
Movement between various building materials

These are filled with elastic materials (such as sealants or rubber profiles) that get compressed and expanded by the floor movement.

Step-by-Step: How Expansion Joints Are Installed in Flooring

Step 1: Design and Planning

Prior to installation, it is necessary to:

Establish the spacing and location of joints dependent on slab size, climate, type of material, and building structure.
Refer to building codes and industry standards (such as ACI 224R for concrete).
For epoxy or tile floors, align the joint pattern with the substrate’s control joints.

Typical spacing for expansion joints:

Every 20–30 feet for concrete slabs
Near columns, walls, and structural breaks

Step 2: Joint Creation (During Concrete Pouring or Surface Prep)

Depending on flooring type, joints can be:

Created during concrete pouring with removable joint formers or expansion joint strips
Cut into cured concrete with a saw (saw-cut joints)
Built into overlays or toppings as part of surface preparation (particularly with epoxy or polyurethane floors)

Joint width is generally between 6 mm and 25 mm (1/4″ to 1″) depending on anticipated movement.

Step 3: Joint Cleaning and Preparing

Once the joint has been formed or cut:

Clean away all dust, debris, and laitance
Vacuum or use compressed air for a dry, clean surface

If sealants are used, place a bond breaker tape or backer rod along the bottom of the joint to:

Restrict sealant depth
Avoid adhesion at the bottom

Step 4: Joint Filler or Sealant Installation

Depending on the type of floor and loading needs, various materials are employed for joint fillers:

Elastomeric sealants (polyurethane, polysulfide, or silicone)
Pre-formed rubber or neoprene strips
Flexible epoxy fillers
Metal or PVC expansion joint profiles

Sealant is applied with a caulking gun and finished with a tool to provide a flush finish.

Pro tip: Use chemical-resistant sealants in industrial settings.

Step 5: Installing Surface Coating or Flooring Material

When the joint filler has cured:

The remainder of the flooring material (epoxy, tile, polyurethane, etc.) may be installed.
Make sure that the expansion joint passes through the finish and isn’t capped over — it has to be exposed and operational.

Certain systems call for a metal cover plate or joint profile to span the opening for appearance and increased protection.

Important Considerations

Expansion joints need to be regularly aligned from the slab up through toppings or coatings.
Never grout joints with hard materials unless specifically formulated to do so — they will break under tension.
Occasionally inspect and re-seal expansion joints as part of regular maintenance.
Utilize load-rated joint systems in forklift or vehicle-traffic areas.

Where Are Expansion Joints Typically Used?

Concrete floor slabs
Epoxy, polyurethane, or resin flooring systems
Tile or stone floors
Parking decks and ramps
Industrial warehouses
Commercial kitchens
Airports and malls

Tools & Materials Often Used

Diamond saw or joint cutter
Backer rod
Flexible joint sealant
Caulking gun
Bond breaker tape
Joint profile (optional)
Cleaning tools (vacuum, blower)

Final Thoughts

Expansion joints might be a minor detail when installing your flooring system, but they work hard to keep your system crack-resistant, buckling-preventative, and damage-proof in the long term. Whether pouring new concrete, coating with resin, or tiling, expansion joint installation means flexibility, safety, and longevity.

Need Help With Expansion Joint Work?

If you are doing a new flooring installation or retrofitting expansion joints into a new space, our staff can assist with:

Joint design and layout
Material selection
Professional installation