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Set Shower Base in Concrete — Backfill and Repair Floor

Intermediate20 hours

Part of project

How to Install a Backwater Valve to Prevent Sewer Backups · Step 6 of 6

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In this video

The wet concrete is poured onto the floor in the shower area using a makeshift chute made from a piece of metal flashing. The concrete is spread out to cover the entire footprint of the shower base. The shower base is then carefully lowered into the wet concrete. The installer pushes it down to ensure it is fully bedded and uses a level to confirm it is perfectly flat and sloped correctly towards the drain. He taps on the base to check for hollow spots, confirming it is solidly supported everywhere.

Goal: Install Shower Base

  • Work quickly once the concrete is poured, as it will begin to set. Ensure the shower drain is covered to prevent concrete from falling in.

Used in this video

  • Metal Flashing/Chute (Material: Metal) · optionalDirecting the flow of concrete into hard-to-reach areas.
  • Level (Tool Type: Measuring Tools)Ensuring the shower base is perfectly level after being set in the concrete.
67.9K views18045-60 minutes
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FAQs

Is installing a backwater valve a feasible DIY project, or should I hire a professional plumber?

This is an intermediate-level project requiring significant physical labor, specialized tools (like a concrete saw or a heavy-duty sledgehammer for breaking concrete), and a good understanding of plumbing codes and concrete work. While possible for experienced DIYers, if you're not comfortable with breaking concrete, excavating near sewage lines, or ensuring proper slope and sealing, it's highly advisable to consult a licensed plumber. Improper installation can lead to leaks, blockages, or failure to prevent backups.

What permits or inspections are typically required before starting this kind of major plumbing work?

Absolutely, permits are almost always required for altering your main sewer line. You'll need to contact your local municipal building department or plumbing authority to understand their specific requirements for plumbing and excavation permits. Failing to obtain permits can lead to fines, stop-work orders, or requiring you to remove and reinstall the work if it doesn't meet code. Plan for inspections at various stages, such as after excavation and after the valve installation but before backfilling.

What are the most critical safety precautions I should take when breaking concrete and working with sewer lines?

When breaking concrete, always wear safety glasses, hearing protection, work gloves, and steel-toed boots. For working with sewer lines, always wear impermeable gloves (like nitrile or rubber) and a mask to protect against biohazards and odors. Ensure proper ventilation in the work area. Be extremely cautious of other utility lines (water, gas, electrical) that might run through the concrete slab; call 811 before you dig to mark utilities.

What size backwater valve do I need, and are there different types or brands I should consider?

The valve size must match your existing main drain pipe, which is typically 3-inch or 4-inch PVC in residential homes (e.g., Oatey 3 in. or 6 in. valves are listed as materials). Visually inspect your drain pipe to confirm its diameter before purchasing. There are two main types: normally open (most common, stays open until activated by backpressure) and normally closed (requires manual opening for regular flow); ensure the valve you choose is suitable for your application and approved by local plumbing codes.

Set Shower Base in Concrete — How to Install a Backwater Valve to Prevent Sewer Backups (Step 6, Video 1) | Stesso