How Do You Rough In A Bathroom Plumbing On Concrete Slab

Roughing in bathroom plumbing on a concrete slab requires careful planning and precise execution. Here is a comprehensive guide to help you navigate the process successfully.

Planning

Start by determining the exact location of your bathroom fixtures, including the toilet, sink, and shower/tub. Sketch out the floor plan and mark the drain and supply lines for each fixture. Ensure that the drainpipes will have an adequate slope of 1/4 inch per foot to prevent clogs.

Materials

Gather the necessary materials, including:

PVC pipes and fittings (1-1/2 inch for drains, 1/2 inch for supply lines)
Toilet flange
Sink drain and P-trap
Shower/tub drain and overflow
Concrete screws or powder-actuated fasteners
Shims
Caulk

Roughing In the Drain Lines

Use a hammer drill or concrete saw to cut holes in the concrete slab for the drainpipes. Install the drainpipes and secure them using concrete screws or powder-actuated fasteners. Slope the drainpipes towards the main drain line using shims.

Connect the toilet flange to the drainpipe and bolt it down. Install the sink drain and P-trap.

Roughing In the Supply Lines

Drill or cut holes for the supply lines, which typically run parallel to the drainpipes. Install the cold and hot water supply lines, and secure them using clips or straps.

Bring the supply lines to the desired height and location for each fixture. Use adjustable shutoff valves to control water flow.

Testing and Inspection

Once the plumbing is roughed in, test the drain lines by pouring water down each drain. Check for leaks and ensure proper drainage. Test the supply lines by turning on the water and checking for leaks at the fixtures and connections.

Before closing up the walls and floors, have the plumbing inspected by a licensed plumber to ensure that the installation meets building codes and is safe for use.

Additional Considerations

When roughing in bathroom plumbing on a concrete slab:

Use a level to ensure that the fixtures are properly aligned.
Consider installing a cleanout near the main drain line for future maintenance access.
Caulk around the drainpipes and supply lines to prevent water damage.
Protect the plumbing from potential slab movement by using flexible connectors at the fixture connections.