Careful planning and commonsense rough-in make a well-performing, safe, and easily maintained system. Guaranteed.
Synopsis: According to plumber Dave Yates, good plumbing isn’t rocket science; it’s applied science. He also says that it’s possible to control costs and to do things right when plumbing a house. The start to sensible plumbing in a house is calculating peak-demand load (PDL), or the amount of water needed to accommodate the primary fixtures should they be used simultaneously. With an accurate PDL number, you’ll be able to design a system that gets water to where it’s needed, fast and hot. Other important parts of a well-designed plumbing system include a water heater that’s the right size for the house, valves that work properly, good connections to waste lines, trouble-free venting, adequate insulation around pipes in open walls, properly sealed penetrations, and the proper scald-protection steps.
I saw the problem almost as soon as I descended the stairs to the basement: a single pair of ½-in. PEX lines — one hot and one cold — running 75 ft. along the ceiling, with T-fittings spliced in at intervals to serve fixtures on the three floors above. The master bath’s lines were last along this undersize flow-through system, and as you might guess, the master bath was on the third floor.
What were they thinking? Simply put, they weren’t. Good plumbing isn’t rocket science; it’s applied science. Boil it down and you’ve got about 25% knowledge and 75% common sense. The problem is that most rough-plumbing jobs are won or lost by a bid process that emphasizes cost-cutting over performance. But doing things right and controlling costs are not mutually exclusive ideas. Both of them need to be engaged in designing and installing a plumbing system that makes sense.
At its most basic, plumbing is simply the practical application of hydraulics and physics to…