How to use plumber’s tape correctly

Plumber’s tape is known by various names – Teflon tape, thread tape, or PTFE tape – but no matter what you call it, this type of plumber’s tape is essential for ensuring clean, leak-free connections when working with threaded pipes and fittings. Plumber’s tape is made of polytetrafluoroethylene (PTFE, also called Teflon) to create a watertight seal between threaded connections.

When plumber’s tape is wrapped around the external threads of a pipe or fitting, this layer of Teflon fills the gaps between the threads and prevents water from getting through. However, if plumber’s tape is not applied properly, it can fray or contract as the threads are screwed in, destroying the seal. This guide will teach you how to properly use plumber’s tape.

What is plumbers tape used for?

Before you pick up a roll of plumbing tape, make sure you know exactly how to use Teflon tape in plumbing. While plumber’s tape helps prevent leaks, it is not emergency plumber’s tape for existing leaks. Instead, Teflon tape is an “incredibly effective tool for creating a tight seal around pipe thread connections,” says Dustin Smith, founder and master plumber at Smith’s Plumbing Services in Memphis, Tennessee. “Plumber’s tape is a thin plastic tape coated with PTFE, a material known for its non-stick properties. PTFE helps prevent leaks by creating a barrier between the threads of the pipe and the fitting,” he explains.

Plumber’s tape has many uses for residential plumbing, including:

• Faucet installation: Wrap the tape around the male threads of the supply lines when connecting them to the faucet body.
• Garden hose connections: Seal the threads between garden hose connectors to prevent wasteful water leakage.
• Connections for irrigation systems: Seal screw connections in sprinkler systems and other irrigation system components.
• Pipe repair: Replace old plumber’s tape with new plumber’s tape to fix a slow leak between threaded connections.
• Installing the shower head: If replacing a leaking shower head, seal the threads on the shower arm before attaching a new shower head.
• Toilet installation: Seal the threads of the water supply pipe to prevent leaks from the bottom of the toilet tank.
• Valve installation: Before installing a threaded valve, tape the threaded pipe with tape to prevent water from entering.

Before you begin

There are a few things you should consider before learning how to apply plumbing tape. Pipe threads are primarily sharp. If you don’t pay attention to how much pressure you apply, you could end up cutting your thumb or finger. Additionally, you should typically wrap plumber’s tape around the threads two to three times. Exceeding this amount can cause the threads to not close properly, resulting in leaks or even damaged connections. Additionally, you should never burn or heat tape as the resulting gas can be dangerous indoors.

Smith points out that “plumber’s tape is typically sold in rolls of varying widths.” The most common widths are 1/2-inch, 3/4-inch, and 1-inch. “In general, you would use ½-inch tape for ¼-inch to ¼-inch tape Use ½-inch pipe, ¾-inch tape for ¾-inch pipe, and 1-inch tape for pipe 1 inch or larger wide. Teflon tape also comes in different colors depending on the specific purpose of each type of tape.

• White tape: Commonly used by DIYers and plumbers for copper or brass water pipe connections.
• Pink tape: High density tape used by plumbers and pipe fitters for water pipe connections.
• Yellow adhesive tape: Used to seal the threads between gas line pipes and fittings for propane, butane and natural gas.
• Green ribbon: The grease-free and non-flammable version is intended for use on oxygen lines.
• Gray tape: The gray tape is thicker than the other tape types and is designed for stainless steel fittings.

STEP 1: Clean the threads of the pipes and connectors.

First, ensure that the threads of the pipe and fittings are completely clean and free of debris. Even a little dirt can prevent the tape from providing a waterproof seal. If the threads appear dirty, spray them with an all-purpose cleaner and then clean them with a soft cloth.

Although plumbing tape is waterproof, if water gets trapped in the threads, it can cause the tape to not seal completely. Therefore, be sure to clean both the male and female threads and allow the threads to dry before applying tape or attempting to connect fittings.

STEP 2: Align the tape with the second thread on the outer tube.

Locate the start of the pipe’s external threads as the tape will be applied in line with the second thread from the end of the pipe – the first thread should be left uncovered. This starting position prevents excess tape from running over the end of the pipe and blocking water flow. Over-winding a pipe can cause its threads to not seal tightly and can place external pressure on the fitting, potentially causing leaks and damage.

Grasp the band with your dominant hand and hold the male tube with your other hand. Align the edge of the band with the second thread. As you wrap the pipe, use your thumb to smooth the tape so that it lies completely flat against the threads.

STEP 3: Apply the tape in the thread direction.

Continue wrapping the tape around the pipe, following the thread direction, to ensure a perfect seal once you screw the valve or fitting into place. Each new wrap should overlap the previous wrap by approximately half the width of the tape.

For most residential plumbing, you should use about two to three wraps of plumber’s tape, making sure to wrap the tape in the direction of the thread spiral. Although most pipe threads run clockwise, it’s always a good idea to double-check the direction before you start winding the tape.

• Small ¼” to ⅜” pipes Only about one or two windings are required.
• Medium ½” to ¾” pipes should have about two to three windings.
• Large 1″ to 1 ¼” pipes need about three to four packs.

STEP 4: Press down on the tape and pull to tear it off.

Once you’ve wrapped the tape around the threads, press the tape down with your thumb and smooth it along the threads. Ideally, the tape should fit tightly between the threads so that you can clearly see their shape. If there are any bubbles, bunched edges, or foreign objects that may have been missed during the cleaning process, you will need to remove the tape, clean the threads, and reapply them.

DIYers who want a little more leak-proofing should consider applying a pipe thread sealant to plumber’s tape. After the tape is attached, you can screw in the threaded piece. Hand-tighten the connectors until they stop, then tighten the connection with a wrench or pliers.

Final thoughts

Plumbing tape has a wide range of uses in domestic plumbing and is therefore an indispensable part of every plumbing toolbox. It is both affordable and effective and ensures that threaded connections remain leak-free when used correctly. If you find that the tape frays or contracts when installing the threaded connector, simply unwind the tape, clean the pipe and threaded connectors again, and try again. The band should tighten with the fitting and not be forced to loosen.