how to

seal concrete cracks


recommended products:
DAP® 3.0™ Advanced Self-Leveling Concrete Sealant, DAP® Concrete Watertight Filler and Sealant, and DAP® Concrete Patch can be used to fill and seal cracks and gaps up to ½" for a smooth surface, for energy savings, and/or to prevent the gap from filling in with water after rain. For gaps above ½ " in diameter, use a foam backer rod first, then apply the caulk over the backer rod.

project instructions:

  1. Be sure to read the entire package to ensure you have all materials the job will require and to budget for dry times in your project. Carefully review safety precautions on the package.
  2. Clean and dry the surface you will be sealing to ensure it is free of all dirt, dust, grease, old caulk, oil, debris and loose or damaged concrete. (To remove old caulk, use DAP® Caulk Be Gone® for latex caulks or DAP® Silicone Be Gone® for silicone caulks; or a utility knife or a caulk removal tool. Once completely removed, wipe away any debris.
  3. Apply duct or electrical tape to mask off areas around the joint where the sealant should not appear and to help give a straight line.
  4. There are many different nozzle designs on caulk cartridges. Read the instructions of your selected product for instructions on cutting the nozzle. Some nozzles have an inner-foil lining that needs to be punctured or a removable nozzle covering an inner plastic seal that also needs to be cut. If you have selected a product in a squeeze tube, cut the nozzle at a 45° angle with scissors or a utility knife and squeeze the product into the joint.
  5. Load the cartridge into the caulking gun. Applying steady pressure to the trigger, fill the joint in the concrete with an even bead of sealant. It is best to push the caulk ahead of the nozzle to ensure that it gets in the joint for a proper seal. Follow using a finishing tool such as the DAP® Pro Caulk™ Tool Kit to smooth the bead for a professional- looking finish.*
  6. If you applied duct or electrical tape, remove the tape prior to the sealant skinning over. To correctly remove tape, lift the edge up at a 45° angle away from you, and carefully place in a trash can.
  7. Wipe away excess sealant with water and a damp cloth before the caulk dries.
  8. The DAP CAP™ is ideal for storage if later use of a partially-used container is desired.
  9. * self-leveling sealants: If using a self-leveling sealant, a more uniform fill or neater appearance may be obtained by wetting a trowel or putty knife with water and tooling the sealant lightly.

clean-up and other information: Generally, latex-based products are soap and water clean-up. Silicone products must be cleaned up with solvent cleaners. Carefully read all label instructions before beginning your project. See the following product attribute chart for select DAP products providing valuable information to aid in your product selection.

which product should I use?

DAP® 3.0™ Advanced Self-Leveling Concrete Sealant DAP® Concrete Watertight Filler and Sealant DAP® Concrete Patch
quality advanced better better
paintable yes yes yes
time before painting 3+ hours 72 hours 72 hours
clean-up mineral spirits soap & water soap & water
unique feature Caulk and expose to water after just 3 hours can be used on vertical concrete cracks squeeze tube eliminates need for caulk gun

this is a great project to:

  • prevent water from entering the crack after rainfall (especially in cold weather when this water build up can freeze and make cracks wider and deeper)