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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.

A cracked concrete surface
Don’t get tripped up on cracks in sidewalks and other concrete surfaces. This short guide explains how to seal them with concrete caulk.


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. Its versatility makes it the best concrete sealant for a variety of projects.

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 concrete sealant that can be used for additional projects, check out Loctite’s range of caulks and sealants.


  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 concrete sealant. It is a good idea to use a stiff, high-density backing 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; concrete 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 concrete 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 concrete 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 concrete 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 concrete sealant with a sharp-edged tool.
Thin cracks in a concrete wall.
Although cracks like these have a certain aesthetic appeal, you should apply concrete sealant to them before they cause problems.


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 or crack sealants.

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’s a concrete sealant that 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 concrete joint 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.

Products used

  • loctite pl concrete non sag 10oz cartridge
    Loctite PL Non-Sag Concrete

    Forming water and weatherproof seals in all exterior concrete and masonry gaps and joints.

  • loctite pl concrete self leveling 10oz cartridge
    Loctite PL Self-Leveling Concrete

    Repairing and sealing concrete and masonry. One-component, self-leveling.

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