Notes from Windward: #70


Replumbing Finney

PEX is so much better


     After much cleaning, painting, and general repairs Finney Trailer has become a clean, comfortable place to live. The last major project is to get running water.

     When the trailer was vacant for a number of years, it underwent many freeze and thaw cycles. Efforts had been made to repair the split copper with hose clamps and radiator hose, but most of the remaining copper was split or joints pushed apart. After assessing the situation I decided it would be cheaper and easier to replace the longest, most damaged runs of pipe with PEX tubing.

brass PEX tee and clamps

     PEX tubing is made from cross linked HDPE (high density polyethylene) polymer. The HDPE is melted and continuously extruded into a tube. PEX plumbing has been in use in Europe since about 1970, and was introduced in the U.S. around 1980. The use of PEX has been increasing ever since, replacing copper pipe in many applications, especially radiant heating systems installed in the slab under floors or walkways. Interest in PEX for hot and cold water plumbing has increased recently in the United States.

      PEX has several advantages over copper, iron or rigid plastic pipe. It is faster and easier to work with, and since it is flexible it requires fewer fittings (no elbows). Fittings have a hose barb that fits into the tubing, and a metal clamp cinches the tubing tight over the barb. A special tool crimps the clamps, and since it takes 20 seconds (with the tool) instead of 20 minutes (without the tool) to install a fitting, I found it worthwhile to personally invest in the crimp tool (about $56.00).

the nifty PEX crimping tool

     PEX is also cheaper than other options, partly because it is lightweight and can be shipped in rolls, so saves freight and fuel costs. Because PEX is flexible, water hammer effects are not much of an issue so it is much quieter than metal pipe. PEX resists freezing because it expands more than metal pipe and does not conduct heat to the air as readily as metal pipe.

      Lindsay helped me stretch the coil of PEX pipe from the kitchen to the bathroom to cut two lengths of about 40 feet. I duct taped the two pipes (hot and cold) together and we fed them into the access hole beneath the kitchen sink. Then I donned my Tyvek coveralls and crawled under the trailer.

      When I removed the old pipe, I tied a string to one end so the string was pulled through where the pipe used to run. I now tied and duct taped the string to the new pipes, and with Lindsay in the kitchen pushing the pipe down the hole I used the string to help pull the new pipe into position beneath the floor. We measured correctly, and after much grunting, pulling and flailing about in fiberglass insulation, the new pipe was in place.

      To prevent freeze damage in the future, I ran 50 feet of rope lights next to the new pipes. I have used rope lights in the past to protect plants from freezing weather, and they were cheaper and more streamlined than heat tape designed for pipes. Fire danger should not be an issue since they are not touching anything flammable, and are pretty safe anyway. Just to be sure, I will plug them in to an appliance timer that will cycle 4 hours on, 1 hour off through the night. They will only get plugged in when temperatures are forecast to dip into the low 20s or teens.

      Once I replace the insulation in the holes under the house, the lights are probably overkill for freeze protection. My philosophy is "do it right, do it once." When I install something, I don't want to have to repair it for at least 20 years. While it may take a little more time upfront to do a quality job, the time saved down the road by not having to deal with leaks, breaks, or other mechanical failures is more than worth it.

      I have one more trip to the hardware store for the correct length of galvanized pipe to hook up the shower, then I can pressurize the system and see if anything leaks.

     If I'm really lucky, I'll soon have one of my favorite things about our industrial society; pressurized hot water!

Notes From Windward - Index - Vol. 70