Four Common Pipe Sealing Methods And How To Know Which One To Use


One of the most frustrating problems for homeowners is dealing with a leak. Whether it's water, air, natural gas, or sewage, leaks can be annoying or even dangerous in some circumstances. However, while many homeowners are capable of performing basic plumbing jobs around their home, there is one aspect that is often overlooked: knowing the proper sealing methods when joining pipes to fittings. Below is a guide to the most common methods and how to know which method to choose for your situation:

Common pipe sealing methods

There are several methods for successfully sealing pipes to fittings and to each other,  Below are some of the most common that are in-use today:

  • Cement - smooth PVC pipe and fittings are joined using a special cement that softens and "welds" the plastic together. The joint created by PVC cement is strong and permanent.
  • Tape - thread-seal tape, which is made from polytetrafluoroethylene (PTFE), is ideal for using on pipe and fitting threads. It consists of a thin, non-adhesive tape that is wrapped around threads several times before insertion into the female end of the fitting or pipe. Thread-seal tape provides lubrication for the threads during insertion and removal, and it also acts as a gap sealer to create a leak-proof connection.
  • Dope - pipe dope is a sealing material that is applied to threads. There are various kinds of pipe dope made by several manufacturers, but it usually consists of some type of base material, such as clay, and lubricating materials. The compound acts as a lubricant for the threads during insertion and removal, and it fills any gaps between the threads. Pipe dope is non-hardening and non-permanent.
  • Inherent - some pipes and fittings are designed to create a leak-proof connection once the two are attached to each other. Tapering threads on the end of a pipe permits the pipe to deeply enter its fitting; when the threads from the pipe and fitting match up with each other, it creates a tight seal due to the compression of the components.

Knowing what to use

Knowing what options are available is helpful, but you should know which one is best for your specific application. The wrong method can lead to more leaks or cause damage to attached components. So if you have any questions you should look at sites like Here are some hints to keep in mind when choosing a pipe sealant:

  • If you need to be able to take apart your pipe and fitting, you need to use threaded connections. PVC pipe can be slip-fitted, but the connection is prone to leakage and will also fail if disturbed too much. The only way to securely join PVC is with cement, and you will not be able to take the pieces apart once joined.
  • Never use pipe dope on PVC or other plastic pipe threads. The oily materials inside of pipe dope can chemically react with the PVC and weaken the threads.
  • For sensitive applications that need to maintain the highest levels of purity, such as hydraulic lines, avoid using thread-seal tape. Tiny pieces of tape can break or come free from the joint and clog the lines or downstream components.
  • With many tapered pipe connections, no thread sealing method is necessary to form a leak-proof connection. However, tape or dope can provide lubrication which is helpful should you need to take apart the pipe in the future; otherwise, the compressed connection may be nearly impossible to undo.
  • For iron and other corrosion-suspect pipes, dope is the recommended way to seal the joints. Rust can eat away at a joint, resulting in leaks or failure, but the oils contained in pipe dope will help create a corrosion-resistant seal.
  • Large diameter threaded pipe should be sealed with pipe dope whenever possible, as tape can be difficult to wrap around the bigger pieces.


21 January 2015

inspecting the roof on your home

When was the last time you really looked at your roof? I had no idea how important yearly inspections of my roof was until I found myself footing the bill for a full roof replacement and interior ceiling replacement. Since then, I have learned how to inspect my own roof twice each year. I always inspect it each spring after the harsh winter elements have gone away and again in the fall before winter weather sets in. You can use the information compiled on my website to inspect the roof on your home and make the small repairs that will save you from full roof replacement.