PEX Tubing

Ideal for Radiant Floor Heating

PEX is a type of plastic tubing widely used for radiant floor heating and for all plumbing applications. Although relatively new to the USA (it has been around since the 1990’s), it has been installed in Europe for more than 30 years. It is growing in popularity due to the increased reliability, ease of installation and lower costs for the material than copper.

Advantages

While copper pipe when frozen will split when the frozen water inside expands, PEX allows enough expansion that it can withstand frozen cycles. This is especially important when installing piping in a slab for radiant floor heat when the slab may be exposed to freezing conditions during construction, or when your log home serves as a vacation home and may be uninhabited during the winter months.

PEX tubing is easier than CPVC to install because it comes in a long roll and is threaded through drilled holes and around corners as a single long piece. CPVC, on the other hand, must be cut and fitted, creating dozens of potential leaks at every joint.

Types

PEX is manufactured in three different grades: PEX-a, PEX-b, and PEX-c. Each grade differs primarily in the way that it is produced:

PEX-a is the strong, uniform, and very flexible. It is made using the Engel method.

PEX-b is also very flexible, strong and uniform. It differs only in the style of manufacturing, using the Silane method.

PEX-c is the most environmentally-friendly method of the three, and it is made using the electronic beam method.

PEX tubing comes in blue and red colors to distinguish between cold and hot water installations, and it is available in sizes from ¼” to 4”, although the most common is ½” and ¾”, especially for radiant floor heating applications.

Applications

PEX is ideal for use in radiant floor heating or hydronic systems, as it can withstand water temperatures as high as 200 degrees. When using tubing for radiant floor heating it is best to use a PEX that contains an oxygen barrier to prevent some of the ferrous system components from rusting. PEX piping also comes in coils ranging from 100' to 2000' making it very versatile for burying in the concrete slab under you cabin.

In radiant floor heat systems, it’s typical to install the tubing in a “home run” system. This means that each area or zone that is heated gets a single length of tubing that runs back to the central manifold. This isolates each area and reduces the chance of leaks or hot or cold spots.

Installation

PEX tubing is easily cut with a knife and it is important not to kink the tubing, which could weaken it. There are specialized tools that make the job a snap: an expander to widen the tip so you can easily slip it on a fitting, copper crimp rings and a crimping tool to join the parts together. There are also systems that use a compression fitting to seal the tubing.

PEX piping is a widely-used, reliable and versatile tubing ideally suited for radiant floor heating and other plumbing applications.

Further Resources:

Log Home Plans for 1BR, 2BR, 3BR and 4BR Cabins

Learn to Build at a Log Home Building School

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