Why a post-tension slab changes the job
A post-tension slab has steel cables running through the concrete, pulled tight after the pour. They are what hold the slab together on Arizona soil. Cutting or nicking one is dangerous for the crew and can damage the foundation, and the repair is expensive.
A curbless shower needs the shower floor to sit lower than the bathroom floor so water runs to the drain. In a home with a wood subfloor you drop the floor between joists. On a slab there are no joists, so the height has to come from the concrete or from the floor around it.
How to tell if your slab is post-tension
- Look for a stamp in the garage floor, usually near the door, warning that the slab is post-tensioned and must not be cut or cored.
- Homes built after the mid-1990s in Gilbert, Chandler, Queen Creek, Peoria, Surprise and much of north Phoenix are commonly post-tension.
- Older homes in central Phoenix, Tempe, Mesa and Arcadia are more often conventional slabs.
- If there is no stamp and no plans, a ground-penetrating radar scan maps what is in the concrete.
Three ways to get a flush entry
| Method | Concrete work | Best for |
|---|---|---|
| Linear drain with a shallow one-way slope | Light, between the cables | Most post-tension homes |
| Raise the bathroom floor around the shower | None | Full remodels replacing all the floor tile |
| Recess the slab in the shower footprint | Heavy | Conventional slabs; on post-tension only with a scan and an engineer's approval |
On a post-tension slab we plan the drain location around the cables, not the other way around. Sometimes that means the drain lands at the entry or along a wall instead of the center.
Waterproofing and water control
With no curb to stop water, the waterproofing has to run past the shower into the bathroom floor and up the walls, tied into the drain. The floor slopes ¼ inch per foot toward the drain, and a fixed glass panel keeps spray in. The pan gets flood-tested before tile.
Cost, permits and timing
Cutting a slab or moving a drain is permitted work in Valley cities, and the drain is inspected before the concrete is patched. Confirm the requirements with your city. A curbless walk-in shower typically runs $9,800 to $24,000, and an accessible build with a bench and grab bars runs $9,500 to $28,000. The scan and concrete work usually add a day or two to a normal shower schedule. We confirm the slab type and the method at the free consultation, before you get a price.
Key facts
- Possible on post-tension?
- Yes, with a scan before any cutting
- Most common method
- Linear drain with a shallow slope
- Floor slope
- ¼ inch per foot to the drain
- Walk-in shower price range
- $9,800–$24,000
Related questions
Where we do this work
Services: Walk-In Shower Remodel · Accessible & Aging-in-Place Bath
Bathroom remodeling in Gilbert, Chandler, Queen Creek, and across the Valley.