Homeowner Forum / Plumbing / July 2010

I've never used pex pipe, so I hesitated to answer.  I assume it's
rated for use underground.  Plumbers have been doing this with soft
copper for years.  Especially where winters are rough, how else would
you pipe in a slab house?  The key is to have no joints underground,
but always loop up into a wall.

Pex is the industry given name for a form of plastic plumbing lines for water
supply in a new home. The correct name is cross-linked polyethylene. A
special manufacturing process has created a durable plastic ideal for use in
water supply lines. PEX tubing is made from a plastic created from molecules
of high-density polyethylene that have been permanently linked together by a
process called cross-linking. There have been attempts in the past to develop
plastic lines and these have met with varying degrees of success or lack
thereof.

Pex may be installed under the slab as well. Where it passes through the
concrete it does not require a sleeve as it does not react with the concrete.
We have found the better way to install is overhead. In our homes there are
no water lines in the foundation. Consideration must be given to protection
from freezing when installed in such a manner. This of course is no problem
as our entire attic is insulated space since we apply our insulation to the
underside of the roof.

Air ventilation
http://www.airventilator.com