Plumbing Rough In
Plumbing rough in is a topic that we cover on every new home project. It is important to understand that plumbing rough in for your home begins in the basement if you are planning one. With a basement you need an exact layout of your plumbing rough in before the concrete floor is poured.
Plumbing rough in describes the piping that is installed before the finished walls are in place. The most common products used for plumbing rough in today are PEX tubing for potable water systems and PVC (polyvinylchloride) rigid piping for DWV (drain-waste-vent) systems.
PEX has become the drinking water supply product of choice because it has the following desirable properties. PEX resists corrosion and scale buildup, it maintains its strength and flexibility at temperatures ranging from below freezing to 200 degrees Fahrenheit. PEX is a cross-linked polyethylene which is relatively new technology but it has been around since the 1980’s.
Let’s talk about the fresh water system of our plumbing rough in system first. PEX stands for Poly Ethylene Cross (X)-Linked. It is the cross-linking process that makes PEX strong, safe and reliable, and it is how this process is done that determines what grade, or category, the PEX belongs to. Depending on the grade of PEX that you choose, the flexibility, strength, and uniform nature of the material will be affected.
The letters tell you how the PEX was created and the quality of the PEX, with “A” being the highest grade, followed by “B’, and finally “C”. PEX-a is made using the Engel (or peroxide) method to crosslink the molecules of polyethylene. With this method, the crosslinking is done at a high temperature above the melting point of the crystals. This “hot crosslinking” produces an incredibly uniform material with no weak spots.
The Engel method produces the strongest, most flexible PEX tubing possible, allowing for an installation with fewer joints and fittings than any other type of PEX. PEX-a also features a strong thermal memory and freeze protection, which means that once the tubing is expanded or contracted, it will naturally go back to its original shape. Since the process takes more time and more sophisticated equipment, PEX-a tends to be a bit more expensive than PEX-b or PEX-c. AquaPEX is the only PEX-a material available for plumbing applications.
If you have ever experienced the sound of a gurgling drain after a toilet is flushed or a tub drain empties then you have experienced the result of an inappropriate or improper vent system.
Each drain outlet needs a venting line that runs up and out of the home. These vents can be connected in an attic space so that they discharge from a common location out of the building so long as the venting system continues to flow in a natural upward direction with no restrictions.
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