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Synthetic Water Supply Pipes? Yes!

Posted February 19th, 2014 under renovations and repairs.

I never thought I would see myself write the headline above!

New ideas in construction always meet with a fair amount of resistance because they have not been tried and proven.

This happened with drywall, particle board, and composite engineered joists and beams, but these are all things we accept as beneficial today.

With plumbing, ABS plastic for waste pipes faced similar resistance.

The latest innovation that is slowly starting to catch on is synthetic water supply pipes (PEX), replacing the familiar copper pipes.

Although synthetic water pipes have been around in Europe for close to 40 years (and one company has been testing them under continuous pressure for more than 35 years with no problems), they are only now starting to gain acceptance in the North American building industry.

A Flexible Material

PEX is flexible, which allows it to change direction without necessarily needing an elbow joint.

Although PEX cannot handle a sharp 90° turn, a wide 90° turn is possible, and so are short, shallow turns.

You could potentially push a single length of PEX pipe all the way from the supply end to the faucet connection without any cutting and fitting of joints.

Not only does this make installation easier, it also gives improved water flow. Some corners that would need to be 90° elbows in a copperpipe system can be replaced with a gentle 90°l bend in PEX.

Each joint eliminated by using PEX also means one less potential point of failure (weak spot) in the system.

Easier Installation

PEX does not require soldering or glue. This removes a time-consuming step, reduces the number of tools and materials, and eliminates the danger of fires from soldering.

Instead, PEX is connected using compression fittings, which are easy to work with.

Where PEX needs to be matched up with existing copper fittings, adapters are available.

Other Benefits

PEX is colored, which gives the option of using red pipes for hot and blue for cold.

PEX can withstand freezing better than copper or PVC. Whereas copper will typically burst with one freeze, PEX can potentially withstand several freeze/thaw cycles. This can be a great boon if the home is left unheated in an emergency.

Some Drawbacks

PEX degrades if exposed to sunlight, becoming brittle. This makes it unsuitable for outdoor installations, or for indoor use in places where it cannot be shielded from sunlight.

PEX may also react to certain adhesives used to apply pipe insulation.However, standard foam-wrap insulation can be used without problems.

But What About Price?

PEX pipe is less expensive than copper pipe, but the fittings for PEX are more expensive than copper.

If you're planning a job that requires many sittings and few feet of piping, the material costs may be cheaper for copper. In most other situations, the material costs for PEX are equal or cheaper than copper.

(Keep in mind that the price of copper has more than doubled in the past 10 years, and may rise further.)

Material costs aside, there's also labour to consider. Remember that PEX requires fewer corners and no soldering. For this reason, labour on a typical job is likely to be less when using PEX.

Overall, it appears that the typical job will be cheaper with PEX, but it pays to do the calculations for your specific situation.

What to Look For

PEX is the common abbreviation for cross-linked polyethylene, and you'll find a number of companies selling PEX piping and fittings.

One particular brand, UPONOR (the company who ran the 35-year pressure test mentioned above) offers a line of PEX parts that come with a 25-year warranty covering not only the pipe itself, but also any water damage caused to the home by any leaks, provided the pipe and fittings are installed by a certified contractor.

Before buying piping and fittings, plan the route the pipe will take and see if you can eliminate some joints by making shallow corners.

And don't forget that you'll need adapters if you're connecting PEX to existing copper pipe.


If you're considering a renovation or addition, think plastic and investigate this great, new, not-so-new material.

Want to know more about plumbing in your home? Just ask me, I'll be happy to help.


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