7 Bathroom Rough-in Mistakes That Cost You Dearly After Tiling

Every year we get calls from people who renovated their bathrooms a few months earlier and now have a leak, a slow drain or hot water that never arrives. Usually the problem isn't the tiles or fittings — it's the rough-in underneath.

1. Wrong drain slope

Drain pipes need a small, measured fall. Too little and waste settles and blocks; too much and water rushes past, leaving solids behind. Ask to see the slope checked with a level before anything is closed.

2. No cleaning eye

The cleaning eye is the access point for clearing a line without breaking. Leaving it out for looks means breaking tiles at the first blockage.

3. Hot and cold lines touching

Without spacing and insulation, hot water cools on the way and cold water turns lukewarm — especially in summer.

4. Tiling before a pressure test

The biggest mistake. The system is filled at higher-than-normal pressure and watched; a weak joint shows up while it's still exposed.

Don't let anyone tile until you have seen the pressure test with your own eyes and the gauge has held steady.

5. Outlets in the wrong place

Choose the basin, toilet and mixer before the rough-in and give the plumber their dimensions.

6. Wrong pipe diameter

A small toilet drain or a narrow supply for a rain shower causes problems from day one.

7. No bathroom isolation valve

A dedicated valve lets you shut off just that bathroom in an emergency instead of the whole house.

Checklist before tiling

• Drain slope measured with a level.
• An accessible cleaning eye.
• Hot and cold separated and insulated.
• Pressure test done, gauge steady.
• Outlets match the fittings.
• A bathroom isolation valve.
• Photos of the pipes before closing.

Our service

With our bathroom renovation service we follow this checklist in every bathroom, pressure-test in front of you and fit sanitary ware neatly with a warranty.

Summary

Good rough-in is invisible; bad rough-in shows up fast. Need a plumber to rough-in your bathroom or check a contractor's work? Contact us.