Roughing in bathroom plumbing is far less daunting when you understand how the system works. There are generally accepted plumbing rough-in measurements for sinks, toilets, and bathtubs or showers. In addition, fixture manufacturers typically provide rough-in specifications in their product literature. So, no guesswork or improvisation is needed. Simply follow the rough-in specs for perfect bathroom plumbing.
Understanding Rough-In Dimension Terminology
When speaking of plumbing dimensions, it’s important to understand the terminology. It’s not just a matter of semantics; it’s a matter of standardization and simplification. Centerline, for example, standardizes measurements and makes it easy to understand the distance between pipes without additional complicating factors like pipe width and pipe schedule or thickness. Centerline: As with the term on-center, which is used for construction, the term “centerline” is an imaginary vertical line drawn through a key reference point, such as a drainpipe. For an example of centerline: if two pipes are specified to be 10 inches apart centerline, you start the measuring tape or straightedge at the center of one pipe, then you measure 10 inches over to the center of the next pipe. You do not measure 10 inches between the edges of the pipes. Base floor height: The base floor is considered to be the subfloor in new construction or the top of the finish floor (or floor covering) for bathroom remodel work. Not all dimensions are set in stone; consider these dimensions to be general guidelines. They will vary according to your bathroom. Consult the instructions that come with the fixture (sink, tub, etc.) for more precise dimensions. Supply line/discharge or drain: With bathroom plumbing, pipes either bring water in or take water out. Pipes that deliver fresh water to the bathroom are called supply lines or supply pipes. The braided flexible line that leads into the toilet to fill the tank is an example of a supply line. So are the hot and cold lines under the sink or behind the wall of the shower. Yet the thicker pipe under the sink that removes gray water is a drain line or discharge line.
