Converting a Tub to a Walk-In Shower: What Is Involved
Moving the drain, sloping the floor, waterproofing, curbless or curbed, and whether losing your last tub hurts resale. What the job actually involves.
Most homeowners arrive with the tub already written off. What matters is the order of decisions after that. Two of them are hard to reverse once demolition starts.
Settle the last tub question first
If the tub coming out is the only one in the house, that is a resale conversation as much as a comfort one. Families with young children often want at least one bathtub, and the preference surfaces when you sell. That is not an argument for keeping it. It is an argument for deciding knowingly. In a one bathroom house, a tub with a fixed glass panel is sometimes the smarter answer.
The drain moves, and the floor has to slope to it
A tub drain sits at one end, tight to a wall. A shower drain sits mid floor or in a linear channel along one edge. Relocating it is the real work here. How hard depends on what is under your floor.
With a raised foundation, a plumber works from the crawlspace and reroutes the waste line with room to set proper fall. On slab on grade, which describes a lot of Southern California housing, the concrete gets cut, new pipe run, and the slab repoured. Both are routine. They are not the same amount of labor, and your quote should say which applies.
The floor then has to slope toward that drain. The amount of fall required is set by the plumbing code your city has adopted, so confirm the figure with your local building department. Slope is what actually moves water, so nobody gets to skip it. That is also why large format tile on a shower floor is harder than it looks. Mosaic conforms to a sloped plane. Big porcelain does not, which is where a linear drain helps, letting the floor pitch in one direction.
Waterproofing is the part you never see again
Under the tile sits an assembly: sloped pan, membrane up the walls, sealed corners and seams, correct connection at the drain. Built properly it stays invisible for decades. Built poorly it becomes a stain on the ceiling below or rot in the framing, and the repair means removing all the tile you just paid for.
Ask which waterproofing system a contractor uses and how the corners and drain flange get sealed. Ask whether they flood test the pan before tile is set. That test is the last chance to find a leak before it is buried.
Curbless or curbed
A curbless shower sits level with the bathroom floor. It looks better, it is far easier to use with a walker or wheelchair, and it takes more structure. The floor has to be recessed so the slope happens below the surrounding finished floor, which means modifying framing between joists or building up the rest of the room. On a raised foundation that is usually workable. On a slab it means cutting concrete. A curb avoids all of it. If aging in place matters to you, curbless earns the extra work.
Glass and blocking go in before the walls close
Frameless glass gets measured after the tile is set, then fabricated, so it arrives weeks after the tile crew leaves. Plan for the gap. Heavy glass also needs solid backing at the hinge points, which goes in during framing.
Grab bars follow the same rule. Put blocking in every wall of the shower while it is open, whether or not you want bars today. Adding plywood behind the finished surface is simple work while the studs are exposed, and a demolition project afterward.
Price drivers, and how to compare two quotes
What moves the number:
- Foundation type, and how far the drain travels
- Curbless versus curbed
- Tile size and layout complexity
- Glass, from a fixed panel to full frameless
- Whatever the wall hides, meaning galvanized supply lines, missing blocking, soft framing at the base of the wet wall
Request a line item scope instead of one number. You want demolition, plumbing, the waterproofing system named, tile labor, glass, and a stated allowance for anything not yet selected. Quotes that look far apart usually differ in their allowances and in what each contractor assumed was behind the wall.
Permits
Relocating a drain is plumbing work and generally requires a permit and inspection. Requirements vary by jurisdiction across Los Angeles County, so confirm with your local building department. The contractor should pull the permit under their own license. Being asked to pull it yourself is a warning sign.
The part nobody puts in a brochure
In a room this small, something behind the wall is usually not what anyone expected. Ask every contractor what happens at that moment: who calls you, how a change order gets priced, whether the schedule is updated in writing. Our license is CSLB 1063782. Look it up at cslb.ca.gov, along with everyone else you are considering.