Charleston Home Inspector Discusses Plumbing Pipe Supports

Submitted by Ray Thornburg on Sat, 09/15/2012 - 17:28

blue palmetto home inspection serves charleston

Common  Required Horizontal Pipe Support Intervals




Type of Pipe Commonly Used for  Horizontal Support Requirements
ABS Sewer 4 feet
Copper Sewer 12 feet
Copper less than 1 1/4" in diameter hot or cold water 6 feet
Copper  greater than 1 1/4" hot or cold water 10 feet
PEX hot or cold water 32 inches
Pex-al-pex   32 inches
Cpvc less than 1" hot or cold water 3 feet
cpvc more than 1" hot or cold water 4 feet
PVC cold water, sewer 4 feet
Lead pipe   continuous 
steel pipe   12 feet


Improper pipe support under the home is one of the most common defects that I find during a home inspection. Since space is limited under the home I guess workmen get a little lax thinking no-one is going under there to check it out. However; lack of proper support for piping can cause all sorts of problems. Sagging sewer lines can cause backups and sagging condensate line can clog causing problems. In addition some types of piping need particular types of support. For example copper pipes with galvanized plumbers tape type strapping will result in galvanic action and corrosion. Let's take a look at a few pretty pictures.

Sagging condensate line

       Here is a sagging condensate line with almost no support. You can actually see moisture dripping off of it. Condensate lines should be insulated. They should be continuously sloped downward. Looks like they got a little lazy and stuck it out of the foundation vent to save time.






rusted strap       This metal strap is severely rusted. A sign of moisture problems in the crawlspace. It's touching a copper pipe which will accelerate corrosion. Metal straps should not be used on plastic piping. Another sign of moisture problems in the crawlspace....falling insulation and corrosion on copper piping.






pex no support     Pex should be supported every 32". No matter the type of pipe a provision must be made to allow for expansion and contraction (movement) of the piping material when choosing a hanger type.





Piping in exterior areas, outside walls, attics and crawlspaces or where subject to freezing are required to be protected by insulation, heat or both heat and insulation. This is for areas where the winter design temperature is above 32° or lower (that's most of us that live north of the top portion of Florida). reference 2012 P2603.5 IRC






no insulation or support     Interesting picture shows piping being supported by the refrigeration lines to the air handler. Piping should be independently supported. Using other piping     for support is not allowed.  Sag is clearly seen. Not insulated and dripping condensation. Sewer lines in the background not properly supported either. Horizontal refrigerant lines should be supported at maximum 8 foot intervals (per lennox installation manual).




using brick for support

     Using a brick to support piping is not allowed. Piping must be supported using the structure of the home. In other words laying a pipe on the ground no matter if its a gas line, water supply or drain line is not allowed. It must have a hanger on it.






Blue Palmetto Home Inspection serves the entire Charleston Lowcountry area!

Submitted by Ray Thornburg on Sat, 09/15/2012 - 17:28


Anonymous | Fri, 09/21/2012 - 05:36

I just signed up to your blogs rss feed. Will you post more on this subject?

Ray Thornburg | Fri, 09/21/2012 - 06:49

I don't know as I'm all over the place with my blogs.... thanks for reading