Seams or gaps that exist where you have PVC piping for drains or vents must be sealed. A quick and easy way to seal PVC is with silicone. The pipe must be dry before you apply the silicone; this allows the silicone to set up properly. To seal a PVC pipe with silicon you must first obtain one or more tubes of silicone, then prepare the PVC pipe.

Step 1

Clean the PVC pipe's surface with a damp cloth or rag to remove dirt and debris.

Step 2

Cut 1/4 inch from the tip of a tube of silicone caulk with the utility knife. Insert a nail or a small wire into the tip of the tube to puncture the seal.

Step 3

Insert the tube of silicone caulk into the caulk gun. Press the push plate against the bottom of the tube.

Step 4

Press the trigger to force the push plate into the tube of silicone.

Step 5

Locate the seam or gap at the joint of a piece of PVC. Place the tip of the tube on the seam or gap that you need to seal.

Step 6

Press the trigger until the silicone comes out of the tip. Slide the tip of the tube along the seam or gap to apply a bead of silicone.

Step 7

Dip your finger in a bowl of water to get it wet. Slide your finger over the silicone to create a smooth texture.