Saturday, October 12, 2019

Construction - Plumbing Rough-In Completed - A Challenge for This DIYer

The plumbing rough-in was started in late summer
The original rough-in under the slab floor showing the PEX
 lines emerging from PVC conduits; the black gas pipe was
inserted between the PEX and the PVC to protect the PEX
while shortening the conduits (see photo below).
of 2015 when the waste system and supply lines were installed before the concrete floor was poured.  (Curiously, the
 blog post describing it is by far the most visited post in the blog -- by a factor of 5 to 1 over the next most visited post (rice hull insulation).)  

The supply lines were encased in PVC pipes for protection while slinging the crushed rock base for the concrete and pouring the concrete itself.  Both the waste and supply lines were stubbed up high enough to avoid accidental clogging by concrete.  The present post takes the rough-in from there.  (Clicking on the photos enlarges them for a closer look.)

Waste Lines
The red circles enclose the shortened PVC conduits; the 
green circles enclose PEX stub-outs for two bathroom
 sinks; the OSB is left-over roof sheathing that will provide
 secure anchorage for cabinetry and mirrors
The layout of the waste lines followed standard protocol but was definitely a stretch for this DIYer even after plenty of research ahead of time.  My thanks go out to my stepson, Keith, who, by virtue of owning and managing a host of rental properties, could add his expertise to the project.  And I am almost embarrassed to admit to the amount of pipe we wasted getting to an workmanlike result.   

Despite being so challenging, the waste system is sufficiently standard that it merits little description here.  There were two minor complications though -- a last-minute addition of a full bath adjacent to the second floor bedroom that required a long waste run to the central stack.  And the vent from the auxiliary kitchen sink located on the south wall had to travel quite a distance to avoid protruding through the roof in view of the public or close to a window.  The lack of partitions on the second floor in which to conceal the central stack vent made for a longer run as well.

Supply Lines
The PEX supply lines were far more interesting than the waste system.  It took some online research and a few new and borrowed tools (like a crimper for the crimp rings that secure tubing to fittings) to bring the task into the realm of this DIYer. 

Each supply line originates from a manifold located next to the incoming water main in the "vertical basement" and terminates at a single faucet or appliance -- a "home-run" system.  The cold water passes directly through the manifold from the main into the cold water (blue) PEX lines.  Hot water takes a bypass through the water heater before traversing the manifold to the (red) PEX lines.  Cut-offs are located on the manifold rather than under faucets or next to appliances such as the dishwasher or washing machine.  This means that, in the future, when a line needs to be closed for some reason, like changing a faucet, it will be shut off at the manifold, sort of like flipping a circuit breaker at the service panel for working on an electrical circuit.  
Notice PEX lines entering the PVC
conduits that protrude from the floor;

also notice above the PEX the race-
way containing Romex cables on their
 way to the service panel and,above
 them, the gas line to the water heater
and kitchen range.

As described in the post mentioned in the first paragraph, all the PEX lines were run below the floor inside PVC pipes.  In addition to protecting the PEX until the floor was poured, the PVC also affords the opportunity to use an existing PEX line to pull a new line in place in the unlikely event of a leak below the floor or some other unexpected problem crops up. The nearby photo shows the blue cold water lines taking circuitous routes from the manifold to the PVC pipes while the red hot water lines emanate from the bottom of the manifold and enter the PVC pipes immediately thereby minimizing the time it takes for hot water to reach its destination.

Tankless (on demand) Water Heater
The ubiquitous tank-type water heater heats water ahead of time, then, if it isn't used right away, it keeps heating it anytime the temperature in the tank falls below a certain mark.  A tankless heater is much more energy efficient because water is heated only once when it is actually being used.  Also, the amount of energy needed to heat a given amount of water the first time is much less for the tankless heater than for the tank type.  Still another energy-saving feature of tankless heating is that heaters come in many sizes for matching hot
Tankless water heater before the
  gas line and vent were connected.
water demand with, say, number of bathrooms.  And it seemed to me while researching water heaters that there are more Energy Star models available among tankless vs. tank type.

Flood Protection
Red arrow points to the master cut-off valve;
the green arrow points to the automatic emergency
cut-off valve.
As is typical, the water line from the street has a master cut-off valve that controls the flow to the entire house.  What is not typical is a secondary emergency-activated cut-off such as the Water Cop System that automatically closes an auxiliary valve just upstream from the master cutoff should any of its wireless senors on the floors of the bathrooms, kitchen and laundry room detect excessive water on the floor from a leak or overflow.  This backup system will give us peace of mind, especially when no one is at home.

Gas Lines
The gas lines to the water heater and kitchen range were also a challenge.  My prior experience had been with black pipe so using flexible tubing required considerable prior research and new-found familiarity with unique fittings.  It helped to have, a phone call or email away, a plumber acquaintance in a distant state who didn't mind sharing his expertise.  My fears that the system would not pass pressure testing were realized at first but, the only leak was finally found and fixed and air pressure was maintained for the requisite 20 minutes.