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Concrete sealants: Simple solutions for heavy-duty projects

Reach for your concrete sealant if you need to fix cracks in sidewalks, walls, floors, or other concrete surfaces. While some of these occurrences are simply unsightly, others, like gaps in sidewalks, can be dangerous and need to be repaired quickly. If your next DIY project involves sealing a concrete joint or crack, read on for tips on selecting and applying the proper concrete sealant to a range of materials.

What is concrete sealant, and what can you use it for?

Generally speaking, you can use concrete sealants to repair or protect concrete surfaces.

If you have a repair project at hand, you will want to use a flexible filling material like Loctite PL Concrete Self-Leveling Polyurethane Sealant to repair driveways, garage floors, concrete floors and decks, and sidewalks. If you think the name is the game, you might be surprised to learn that some concrete sealants can repair materials besides concrete. For example, you can also use Loctite PL Concrete Non-Sag Polyurethane Sealant to bond materials to brick, stucco, metal, wood, vinyl, fiberglass, and other substrates.

While this guide focuses on repairs, it is worth noting that you can seal entire surfaces like concrete floors to protect them and make them easier to clean.

The name of the right product for your project might not contain the word “concrete.” If you are looking for a product you can use for other projects as well, check out Loctite PL Heavy Duty Sealant.

Applying concrete sealant

  1. Clean the surface of all dirt and debris, including unsightly stains on the area you want to seal, and remove any substances like oil, grease, wax, and mastic compounds. If you use a fluid cleaner, let the area dry before you apply the sealant. It is a good idea to use a stiff, high-density back-up material or backer rod for joints that might easily be punctured—for instance, in areas where stilettos are worn.
  2. Wear gloves to protect your skin; the sealant may cause temporary stains.
  3. Check for temperature restrictions for your product and make sure you can apply it under the planned conditions.
  4. Cut the nozzle to the desired bead size at a 45-degree angle and puncture the inner seal.
  5. Test one joint or area before applying the concrete sealant to your entire project to make sure you get the results you want.
  6. Prime the surface if your sealant requires primer. Let your primer dry before applying the sealant. Depending on the ambient conditions, your primer will be ready for sealant after 15 to 30 minutes. Make sure to prime and seal on the same day.
  7. Apply your sealant with a steady pressure, forcing it into the joint in the proper direction – check the manufacturer’s instructions to find out if you need to fill joints from the bottom and when to perform dry tooling, if required. The instructions are generally valuable sources of information; even within the same product family, sealants may have different cure times, for instance. If you use Loctite PL Concrete Self-Leveling Polyurethane Sealant or Loctite PL Concrete Non-Sag Polyurethane Sealant, the depth of the sealant you apply should be half the width of the joint.
  8. Clean your tools and any uncured sealant residue immediately upon completion of your project using mineral spirits. If necessary, do this in a well-ventilated area that opens up to the outdoors. You can carefully cut away cured sealant with a sharp-edged tool.

When should you use which concrete sealant?

Not all sealants are suitable for all projects. Since Loctite never lets you down, it has a range of products that will make your project a success, whether you use them as concrete joint caulk or sealants for concrete.

Foundation, walls, and masonry. If you need to repair concrete, brick, stone, or masonry, you will need a product that forms permanent waterproof and weatherproof seals for all kinds of exterior gaps and joints and that can withstand harsh environments. That means Loctite PL Concrete Non-Sag Polyurethane Sealant is the right choice: it is suitable for repairing cracks in vertical and horizontal surfaces and bonds to concrete, brick, stucco, metal, wood, vinyl, fiberglass, and other substrates. This product generally does not require a primer for applications involving concrete. Make sure your concrete is fully cured before applying this sealant.

Driveways, sidewalks, floors, and decks. These surfaces are exposed to pedestrian and vehicular traffic, so your sealant will need to resist abrasion and tear. Additionally, if you are sealing contraction/expansion joints on these surfaces, you will need a sealant that forms flexible bonds that withstand joint movement without distortion or failure. Loctite PL Concrete Self-Leveling Polyurethane Sealant does all that and more: it is virtually unaffected by extreme temperature changes and can be painted to blend in with surroundings for a professional look. You can use it for old or new concrete. If you are applying it to fresh concrete, make sure it is fully cured before you start sealing.

Stay flexible! Flexible, elastic bonds expand and contract when construction materials move. That flexibility protects the original seal and helps it stay resistant to weather, stress, and movement.