How to Repair Pipe Leaks With a Foam Gap Filler

Updated February 21, 2017

A small leak in your plumbing can cause big problems in your home. Warped wood and damaged drywall are just some of the problems associated with leaking water. Fortunately, you don't have to replace entire sections of piping if you're dealing with a small leak. Use foam gap filler to create an airtight seal around the leak. This prevents air from entering the pipe and water from escaping. This simple solution gets your pipes in working condition in short order and saves you the trouble of making a substantial plumbing replacement.

Turn off all water to the house. You do not want any water leaking from the pipes during the repair process.

Dry off the pipe section that needs the repair. Also, inspect the area for any dirt, debris, or grease. Debris and grease prevent the foam from adhering to the piping properly and prevents the formation of an airtight seal. Use a clean towel and water for dirt and use a grease cleaner to remove any grease build-up.

Hold the foam gap filler spray can in an upright position and spray around the pipe. Make a ring around the entire circumference of the pipe and make sure the foam covers the leak area. Remember that foam gap filler expands in size by roughly 10 per cent, so you don't need to spray excessive amounts of this chemical to cover the leak. The foam enlarges and covers a wider surface area.

Shape the foam with a putty knife after it has expanded. Complete this step if any part of the foam is viewable to the public, as foam gap filler dries with a lumpy and rather unappealing appearance. You can flatten and reduce the amount of foam with a putty knife, which helps improve the foam's appearance.

Allow the foam to dry completely. Test the foam by touching it with your putty knife. You can turn the water back on if no foam applies itself to the putty knife.


Keep foam gap filler way from open flames (i.e. gas pilots) as the chemicals are highly flammable.

Things You'll Need

  • Towel
  • Water
  • Grease cleaner
  • Foam gap filler
  • Putty knife
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About the Author

David Montoya is an attorney who graduated from the UCLA School of Law. He also holds a Master of Arts in American Indian studies. Montoya's writings often cover legal topics such as contract law, estate law, family law and business.