Repairing & Sealing Horizontal & Vertical Expansion Joints | QUIKRETE: Cement and Concrete Products
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A great way to view and understand your building or repair project before you get started. Find out just about everything you need to know by watching the video below.

Repairing & Sealing Horizontal & Vertical Expansion Joints

Expansion joints are cuts in concrete slabs, or the joints between walls and concrete slabs, that go completely through the slab to the base material. The purpose of an expansion joint is to allow the concrete slab to expand and contract with temperatures changes, without cracking the slab. Expansion joints must be sealed with a flexible sealant, like QUIKRETE® Self-Leveling Polyurethane Sealant or QUIKRETE® Non-Sag Polyurethane Sealant…or an expansion joint strip, to prevent water from penetrating the joint and deteriorating the sub-base. Repairing and sealing horizontal and vertical expansion joints is a project that can be successfully achieved with the right tools, materials and proper surface preparation. Watch the video, to learn how!

Project Instructions

When working with cement-based products, always wear eye protection and waterproof gloves.

Step 1
Sweep out the expansion joints to ensure that any pebbles, dirt or loose debris are removed.

Step 2
Scrub and clean the surface of the repair area with QUIKRETE Concrete and Asphalt Cleaner and a stiff bristle brush.

Step 3
Thoroughly rinse the area, after cleaning, and wait for the area to dry, before applying any sealant.

Step 4
Once the area is dry, add the backer rod (if needed). Backer Rod should be pressed into the joint, allowing a sealant depth of between 1/8 inch and ½ inch.

QUIKTip: Backer rod should be used for joints over ¼ inch.

Step 5
Then, using a utility knife, cut the tip of the nozzle, and insert the tube into a standard caulk gun. Make sure to match the cut to the width of the crack.

Step 6
For Horizontal Applications:

a. Use QUIKRETE Self-Leveling Polyurethane Sealant, and move the nozzle slowly along the length of the joint, allowing the sealant to settle. No additional tooling is necessary.

b. UIKTip: Self-Leveling Sealant is highly fluid and may require an additional application. If this is the case, this should be done immediately, so that the two applications will mend into each other.

For Vertical Applications (or Stucco Walls):

Use QUIKRETE Non-Sag Polyurethane Sealant, and move the nozzle slowly along the length of the joint, pressing the sealant into the joint. Use the tip of the nozzle to smooth the sealant, if needed.

Step 7
Immediately clean up any excess sealant with a commercial solvent or a citrus-based cleaner.

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