Rough in plumbing is, in essence, a "rough draft" of your plumbing installation.
The plumbing rough in is the first step in the complex process of your home's plumbing installation, and one that requires precision on your part. A mistake could lead to problems with waste drainage or water pressure that would need to be remedied later on-an an expensive and time-consuming fix. A plumber can complete plumbing fixture or new construction plumbing and pass inspection by building inspectors.
To help make sure you get things right the first time, here are some tips to keep in mind as you begin your plumbing rough in work.
The best advice for choosing a sink location is this: put it where you want it. But because of restrictions and limitations placed on by local building codes and other regulations, you must take certain things into consideration before the job is completed to avoid confronting a plumbing inspector or to pass inspection by a building inspector. Typically, the sink location should produce the smallest possible bump in your walls that will still allow for proper drainage.
Before cutting into any wall or floor space, consult with local building regulations for validation purposes in order to determine the necessary location for sinks and fixtures to pass inspection by a plumbing inspector.If you use a P-trap, the drain is connected across from the sink or on the other side of the wall where it enters into the main waste supply pipe. If an S-trap is used, then it is connected at the opposite of the drain line, or on the other side of the wall. For example, if you use a P-trap with your sink's drain, it's best to have the sink wall bump out so that both ends of your P-trap are accessible for connection.
If you're unsure which type of trap you'll be using, talk to your local building inspector.
You'll need at least 4" of pipe coming out of the wall into which you're connecting your sinks and toilets. This is because 2"-4" of that length will be inside the wall as it makes connections to either a P or S-trap under the sink or to the main waste line. For toilets, you'll need to install one trap or T-connector for every toilet that's within distance of another.
The best way to access your future plumbing connection points is by removing the drywall and accessing the framing from inside the wall cavity. But this can be a bit tricky if you're not experienced. An easier way to provide access to these points is by cutting holes through the wall below sinks and toilets. If you're not sure where the waste lines are, then it's best to cut out a larger area to avoid drilling into one.
It's up to you whether or not you want to connect wood and plastic pipes using a transition coupling. Transition couplings are either flexible or rigid and can be connected together if necessary. For example, if you run a plastic drain line and need to make a 90° elbow while still staying within your 4" of pipe, you can cut out part of the coupling and install a threaded elbow after connecting it.
The process of plumbing rough in or rough in process involves placing the supply lines that carry water for drinking and washing into bathrooms and kitchens where they connect to faucets and other fixtures. Before any permanent installation can be made, these drain lines must be run through walls, floors, and ceilings. It is called "roughing" because the pipes usually haven't been connected permanently to faucets or fixtures yet and it's just being laid into position temporarily before final connections are completed.
The distance between the water supply lines and drain lines varies for different types of buildings, but it can be as little as 4 inches or as much as 12 feet between water supply lines in older homes. Such a construction project differs from house to house such as for a framed home, the water hammer end is not left unchanged and the same goes for steel frames depending on weather conditions. Plumbing codes dictate the minimum amount of space required throughout different zones of a building, so if there's not enough room near water supply lines or water supply pipes to installing fixtures where they're needed, then additional space must be created.
This is typically completed by creating offset holes in walls to accommodate floor joists or studs that may otherwise prevent the installation of plumbing pipes. If you plan on installing offsets, talk to your local inspector before starting any work to make sure this will meet code requirements with water supply lines or water supply pipes in your area. In New South Wales, plumbing rough in work may require sign-off from a certified professional. Be sure to check your local requirements.