There are multiple concerns raised when considering filling options for expansion and contraction joints. Some of the confusing factors revolve around the most appropriate time for filling. Should it be conducted before or after applying an epoxy coating or before or after applying a sealer? This guide seeks to address all concerns pertaining to filling joints in a bid to attain desirable outcomes in the floor finishing.
Distinguishing Between Contraction and Expansion Joints
Contraction joints (control joints) for a typical garage space appear to be a distinctive plus sign dividing the floor space into four slab sections. They are V-shaped and in some instances, feature saw cuts with precise dimensions of 1-inch depth and 3/16-inch width.
In due time, cracking of concrete slabs is inevitable but the presence of joints align such cracks along the intentionally weakened lines. This prevents cracks from taking random alignment across resistant floor surface which would weaken the integrity of the entire structure.
Expansion joints, on the other hand, are alternatively known as isolation joints and they separate different sections of concrete slabs. Their dimensions feature 1/2-inch width minimum and have to integrate compressible fiberboard filling material. Their main function is to avoid damage that would arise from the expansion and contraction of two slabs if they were in direct contact. An example of an expansion joint is the gap between a driveway and garage floor.
Benefits of Proper Joint Filling for Concrete Floors
- Prevents Cracks and Damage: Properly filled joints help direct natural concrete cracks along predetermined lines, preventing random cracking that can damage the structural integrity of the floor.
- Increases Floor Durability: By using flexible materials like polyurea or 100% solid epoxy fillers, joints can expand and contract without causing cracks to surface on the epoxy coating, extending the life of the floor.
- Improves Aesthetic Appeal: Filling contraction joints before applying epoxy coatings creates a smooth, seamless look across the floor. This eliminates visible gaps and enhances the overall visual appeal.
- Reduces Dirt Accumulation: Unfilled joints can widen over time and collect dirt, debris, and moisture. Filling joints after applying a sealer or coating ensures the surface stays clean and requires less maintenance.
- Prepares for Epoxy or Sealer Application: By filling joints before applying coatings, you ensure that the floor is prepped for an even application of epoxy or sealers, resulting in a smooth and consistent finish.
- Prevents Coating Failures: Using the right filler material prevents telegraphing cracks from appearing on the surface of coatings, which can otherwise cause coating failure and damage the floor's appearance.
- Long-Lasting Solution: Polyurethane fillers are self-leveling and do not shrink after curing, providing a long-term, reliable solution for joint filling, and maintaining the floor's condition over time.
- Easy Application: Many fillers, especially polyurethane, are simple to apply using a caulking gun, offering an affordable, DIY-friendly solution with professional results.
How To Fill Contraction Joints Prior To Applying Epoxy Coating
In improving the aesthetic value of garage floors, many property owners prefer to fill contraction joints to create a balance of elements in the entire floor space. It is only safe to do so with the right combination of materials.
In any instance that the joints get filled with inflexible material and a layer of paint or epoxy is applied, the most likely outcome are cracks telegraphing their way up to the surface of the two slabs via the coating.
The solution here is choosing the polyurea or the 100% solid epoxy filler that is designed with a greater rate of elongation. This actively prevents cracking by flexing whenever the joints expand or contract. The coating stays consistent without cracks as it cannot be pulled away due to its flexible nature. Some of the recommendable products include the 2-Part 100% solids epoxy gel and 2-part polyurea crack filler.
How To Fill Joints After Applying Sealers or Epoxy Coatings
With time, joints become too wide hence collecting a lot of dirt which takes away from the physical appeal of your property. The best time to fill such joints is only after sealers and epoxy coating have been applied.
A Polyurethane joint filler or sealer is the best product for the job as it is self-leveling. Even after curing, this product does not shrink. Its application is easy as enabled by a calking gun and is affordable despite offering long term solutions.
Cleaning out individual joints first is advised but sand should not be used to fill the joints as it is not compressible. The concrete used for filling should be dry for it to adhere perfectly. After application, the entire floor space should be given adequate time (3-5 days) to fully cure without interruption.