Wrap a piece of string around a pipe one time and measure the coiled length of the string with a measuring tape to determine the diameter of the insulation you must purchase.
Measure the length of each water pipe with a tape measure to determine how much insulation to purchase.
Cut the insulation to the length of the pipes with a utility knife.
Open the seam at one end of the insulation and press that end over one end of a water pipe with the seam facing downward.
Press the insulation onto the length of the water pipe with the insulation seam facing downward.
Secure the insulation in place with zip ties positioned approximately every 12 inches along the length of the insulation.