Rough-in plumbing is the initial process of installing water lines, sewer connections and vents. This process begins once the home's foundation has been back-filled and consists of digging trenches for water and sewer lines before laying pipes in their approximate position and filling the trenches with gravel to facilitate drainage. Gravel is then covered by plastic before pouring concrete over the foundation.
The entire rough-in plumbing process typically takes two to four days depending on the overall complexity of the planned plumbing system. Install rough-in plumbing beneath the concrete structure or foundation slab of a home. Place any below-ground electrical wiring in protective tubes or pipes, and lay them at the same time as the rough-in plumbing to ensure an orderly installation.
Create a rough-in plumbing diagram before beginning any construction. Diagrams should include all lines and pipes as well as the materials required to complete the installation process. Install the bathtub water lines before the other pipes because bathtubs are typically large fixtures that cannot be easily moved during or after the rough-in plumbing installation. Keep plans for rough-in plumbing flexible so they may be adapted to a range of different finishing materials that may be used later in the process.