How to Insulate Pipes in a Crawl Space

The hardest part about insulating pipes in a crawl space is the lack of room.

Water pipes should be insulated against cold conditions.Water pipes should be insulated against cold conditions.
It's best, therefore, before actually starting the job to crawl into the area so see if you fit in the space. Next, free the area of any objects in your way--especially sharp items like forks or garden shears. Chances are that you'll either be lying on your back or side, so assume both these positions for possible height restrictions. If you can, lay down a mat to make the ground more comfortable.

Crawl into position with a roll of plastic insulation tape and either scissors or a tradesman's knife. The tape itself looks much like household adhesive tape, though it is not see-through. This will be applied to all bends in the pipe--where angled couplings have been fitted to change the pipe's direction.

Roll the tape--sticky side down--around the pipe 3 inches away from the bend. Roll it down in a spiral fashion toward the bend, then cover the bend and finish 3 inches past the bend on the other straight pipe. Foam insulation tubes generally don't fit well around pipe bends, so the tape offers good insulation protection. Cover all remaining pipe bends in the same fashion.

Measure the first straight piece of pipe in the area that you want to insulate--this will be from one bend to the next--using the tape measure. Add 1 inch to that length to make it a tight fit. Cut a piece of foam insulation tube to that length, using the tradesman's knife or scissors. The foam has a slit the entire length on one side and is hollow in the middle, so push the pipe past the slit and into the middle of the tube.

Pull away the plastic strips protecting the glue on each side of the slit and squeeze the two sides of the slit together with your hands. Continue in like fashion with all the other straight sections of pipe.

Things You Will Need

  • Insulation tape
  • Foam insulation tubes
  • Tradesman's knife/scissors
  • Tape measure


  • Foam insulation tubes come in different thicknesses. Check with your permit office for the required thickness for your area.

About the Author

Steve Sloane started working as a freelance writer in 2007. He has written articles for various websites, using more than a decade of DIY experience to cover mostly construction-related topics. He also writes movie reviews for Inland SoCal. Sloane holds a Bachelor of Arts in creative writing and film theory from the University of California, Riverside.