Remodelers Guide

Plumbing Rough Install

TLDR

  • Get rough in valves, tubs, shower trays, shower liners on site for the plumber to set
  • Mark out toilet rough in dimensions
  • Confirm drains don't land on joists or beams in the floor system below
  • Plan for vent pipes through the roof
  • Mark out cabinets and trim so valves and shutoffs avoid interacting

Overview

Plumbing typically encompasses the piping in a home, which includes water supply, drain/waste/vent, as well as gas. In some cases the plumber may also work on hot water or steam radiant head systems. There are many different types of tubing from copper to iron pipe and plastic.

Prerequisites

  • Concrete slab removed or not poured to allow plumber to install underground drains.
  • Framing should be complete but in remodel situations you may need to leave the subfloor loose for the plumber to install drains.
  • Rough-in valves, tubs, showers, and shower pans should be on site for the plumber to install.
  • Toilet rough in distances should be marked, or specs available.
  • Baseboard trim height marked on wall where toilet goes.
  • Vanity cabinets marked, especially floating cabinets, as well as wall hung or pedestal sinks.
  • Centers for site built tiled showers and shower head height.

Materials / Tools Needed

  • Fixtures: Shower valves, diverters, shower trays, tubs, shower surrounds.
  • DWV: PVC/ABS pipe & fittings, test caps, solvent/cement, cleanout tees & plugs.
  • Water: PEX/copper, fittings, manifolds, stub-out elbows/plates, valves, washing-machine/ice-maker boxes.
  • Gas: black iron/CSST, striker plates, union/drip legs, test gauge.
  • Misc: tub/shower protection, nail plates, firestop caulk.
  • Testing: test plugs, pump.

Layout & coordination

  • Walk the site with the plumber: go over fixture locations and heights, vent paths, joist bays to use/avoid.
  • Mark centerlines and finished-floor (AFF) elevations; confirm tub drains, valve depth vs. tile thickness, and niche locations.
  • Pull specs for hand showers/slide bars.

Inspections

  • Plumbing Rough Inspection: Drains may be required to be pressurized to check for leaks; the inspector will check for proper slope, venting, cleanouts, supports, protection, and firestopping.
  • Gas Pressure Test: New gas lines should be capped and put under pressure to check for leaks with a pressure gauge on.
  • Shower Pan Inspection: Flood test confirmation before tile/backer goes in, after the shower pan has been waterproofed using a rubber Oatey liner, Schluter shower tray or similar product.

Best Practices / Pro Tips

  • Pull valve & trim cut sheets before rough, keep trims on site for your tilesetter to reference. Make sure they are the correct depth in the wall.
  • Keep tub/shower protected.
  • Install shutoffs local to each fixtures. Shutoffs for each group of fixtures may be helpful to service later.
  • Leave the job inspection-ready: tidy, plans open, gauges visible, test levels marked; inspectors appreciate clean sites and clear follow-up.

Client Interaction / Communication Notes

  • Let the client know that there will be an interruption in water and drain service, and that they may need to avoid running water or flushing toilets.
  • Photograph rough ins after they are installed.

Common Issues and How to Avoid Them

  • Mock up a wall to plan for valve depth location
  • The builder should keep plumbing nail plates on hand during inspection
  • Builder should have fire caulk on hand during inspection and do check before the inspector arrives
  • Cover tubs or shower trays before they are installed, leave space around the flange and drain location
  • Make a story pole or mark up the floor plate with tile thickness, backer, centerline etc so plumber doesn't have to guess.