Tub to Curbless Shower (accessibility)
Tub to curbless shower is the aging-in-place and ADA-accessible conversion — the alcove tub comes out and a zero-threshold walk-in shower goes in with no entry curb at all, a single-plane floor sloped to a linear drain at the back or one side wall, structural blocking installed during framing so ADA-rated grab bars can land anywhere later, an integrated tile bench, and an ADA-compliant single-handle mixer with both a handheld and a fixed shower head. The floor structure gets assessed first — most curbless conversions require the subfloor to be recessed (sometimes a sister-joist) or the surrounding floor built up, so the transition from bath floor to shower floor is truly zero-threshold rather than the cosmetic 1/2-inch "almost curbless" that defeats the wheelchair purpose. Ten to fourteen working days. From $8,000 for a standard ceramic curbless build with a linear drain to $16,000 for the full ADA package with bench, three grab bars, ADA mixer, body sprays, and a frameless glass panel. The in-wall plumbing — drain relocation to the linear position and any valve work — subcontracts to a licensed Washington L&I plumber.
Service
What Tub to Curbless Shower Conversion Covers
The curbless conversion is structurally different from a standard curbed walk-in. The pan slopes in a single plane to a linear drain (instead of a four-way slope to a center drain), the entry is at floor level (no 4 to 6-inch tile curb), and the framing carries structural blocking inside the wet wall so future grab bars have something to back into without re-opening tile. ADA Section 609 sets the 250-pound static-load standard on grab bars; ADA Section 608 covers the shower compartment itself (size, threshold, controls). Most homes are not built for curbless out of the box — the floor structure assessment is step one.
Floor Structural Assessment + Subfloor Plan
The first visit assesses what the bath floor can do. Most second-story baths over a basement or first-floor space allow the subfloor to be recessed 1.5 to 2 inches so the curbless pan sits flush with the surrounding bath floor (the joists below get sister-joisted or strapped to compensate for the recess). Some baths cannot be recessed (on-slab construction, structural issues, finish-ceiling height below) and the curbless requires the surrounding bath floor to be built up to the shower pan height — a different but valid approach. We assess on the estimate visit and tell you which method applies before any work starts.
Demo + Subfloor Work + Drain Relocation (Plumber)
Demo of the existing tub and surround happens as on every conversion. The subfloor work (recess or build-up) happens next, with sister-joists or strapping added below where needed. The licensed Washington L&I plumber comes in for drain relocation — the original tub drain in the center of the alcove gets moved to the linear-drain position at the back or side wall, which is a more involved relocation than a standard tub-to-shower drain conversion. The plumber's visit on a curbless job runs 5 to 7 hours.
Framing with Grab-Bar Blocking + Linear Drain Channel
Framing closes with 2x6 or 2x8 horizontal blocking installed inside the wet wall at three heights — vertical-entry grab bar height, horizontal back-wall grab bar height, and bench-edge bar height — so any future grab bar lands on solid wood rather than requiring a rated solid-mount toggle. The linear drain channel (Schluter Kerdi-Line, Infinity Drain Tile Insert, or equivalent stainless channel) gets framed in at the back or one side wall, with its waterproof flange ready to bed into the membrane.
Sloped Pan + Waterproof Membrane + 24-Hour Flood Test
A single-plane mortar pan gets dry-packed sloped at 1/4 inch per foot toward the linear drain (much simpler geometrically than a center-drain four-way slope — every line on the pan runs in the same direction). The waterproof membrane goes on (sheet Schluter Kerdi or rolled-on RedGard/Hydroban), with the linear drain flange embedded and the membrane carried up the walls 8 inches and over the bench. Then the pan flood-tests for 24 hours. Curbless pans get extra attention at the threshold transition because the membrane has to extend out under the bath floor tile to prevent any wicking back.
Tile Install (Slip-Resistant Floor) + ADA Grab Bars
Floor tile is slip-resistant by spec for accessibility — typically a small-format porcelain (2 by 2-inch mosaic or smaller) or a textured large-format tile rated for wet barefoot traffic (DCOF 0.42 or higher per ANSI A137.1). Wall tile is large-format porcelain or ceramic at homeowner's selection. ADA-rated stainless grab bars (250-pound rated per ADA Section 609) install into the blocking we set during framing — typically a vertical bar at the entry, a horizontal long-grip on the back wall, and a bench-edge angled bar.
Frameless Glass Panel + ADA Mixer + Final Trim (Plumber)
The frameless glass panel (3/8-inch tempered, single fixed panel — not a hinged door — to keep the entry barrier-free) goes in last. The licensed plumber returns for final fixture trim: the ADA-compliant single-handle mixer (lever handle, accessible from outside the shower), the fixed shower head, the handheld shower head on a slide bar or hose so a seated user can shower seated, and any body sprays or rain head if specified. Pull-test on every grab bar with full body weight before hand-off.
How the Curbless Conversion Works
Six sequential phases from floor structural assessment to ADA fixture trim — the actual working sequence we run on every curbless walk-in conversion, with grab-bar blocking installed during framing for future flexibility.
Floor Structural Assessment + Subfloor Plan
Estimate visit checks the floor structure (joist depth, span, what is below the bath, whether the subfloor can be recessed 1.5 to 2 inches or whether the surrounding floor needs to build up to the shower pan height). We tell you on the estimate which method applies before contract signing. No surprises mid-build about whether curbless is even structurally possible.
Demo + Subfloor Recess (or Build-Up) + Drain Relocation Plumber Visit
Tub demo, surround down to studs, subfloor recess cut and sister-joisted (or surrounding floor framed up to pan height), then the licensed Washington L&I plumber arrives for drain relocation. The original tub drain in the center of the alcove moves to the linear-drain position at the back or side wall. Plumber visit runs 5 to 7 hours on a curbless job — more involved than a center-drain conversion.
Framing with Grab-Bar Blocking at 3 Heights + Linear Drain Channel
Framing closes with 2x6 or 2x8 horizontal blocking at vertical-entry grab bar height, horizontal back-wall grab bar height, and bench-edge bar height — so future grab bars land in solid wood instead of needing rated toggles. Linear drain channel (Schluter Kerdi-Line, Infinity Drain) framed in at the back or one side wall with the waterproof flange ready.
Single-Plane Sloped Pan + Waterproof Membrane + 24-Hour Flood Test
Mortar pan dry-packed in a single plane at 1/4 inch per foot toward the linear drain (geometrically simpler than a four-way center-drain slope). Waterproof membrane installed (sheet Kerdi or rolled RedGard), drain flange embedded, membrane carried up the walls 8 inches and over the bench framing. Pan flood-tests 24 hours with extra attention at the threshold transition.
Slip-Resistant Floor Tile + ADA-Rated Grab Bars Into Blocking
Floor tile is slip-resistant per spec (small-format porcelain mosaic or textured large-format at DCOF 0.42 or higher per ANSI A137.1). Wall tile is large-format porcelain or ceramic at homeowner's selection. ADA-rated stainless grab bars (250-pound per ADA Section 609) install into the blocking from step 3 — typically vertical at the entry, horizontal long-grip on the back wall, angled at the bench edge. Pull-tested with full body weight.
Frameless Glass Panel + ADA Mixer + Handheld + Plumber Final Trim
Fixed frameless 3/8-inch tempered glass panel (single panel, not a hinged door, to keep the entry barrier-free) installed after silicone cures. Licensed plumber returns for ADA-compliant single-handle lever mixer accessible from outside the shower, fixed shower head, handheld on a slide bar so a seated user can shower seated, and any body sprays or rain head if specified. Final walk-through and warranty paperwork hand-off.
Curbless Shower (ADA Accessibility) Pricing
Final pricing depends on the floor structural work required (recess vs build-up), the tile selection, and the ADA scope (grab bar count, bench size, fixture package). The licensed plumber's portion (drain relocation, ADA mixer trim, fixture work) is included in every quote. Plumbing permit, where required by Seattle DCI or your city, also lives inside the project total. Request a free in-home estimate for an accurate quote.
Tell us the bath layout, the floor structure, and the ADA needs — we will quote the curbless project including the plumber's portion.
Why Aging-In-Place Customers Book Handis for Curbless Conversions
A curbless conversion done correctly is a different project from a curbed walk-in — the floor structure is the first question, not the tile selection. Many bathrooms cannot be recessed without sister-joisting (a second-story bath over a finished ceiling space loses too much head room if you just notch the joists; the right answer is sister-joisting from below the basement ceiling). Some baths cannot be curbless at all without raising the surrounding bath floor by an inch and a half — also valid, but a different scope. The other failure mode we see on bad curbless installs is grab-bar blocking missed at framing because the homeowner did not commit to bar positions yet — six months later they want a bar where the tile has to come down because there is no blocking behind it. Handis installs blocking at three heights during framing regardless of whether you have picked bar positions, because the cost of putting blocking in during framing is twenty minutes; the cost of opening tile later is thousands.
Floor structure assessed first, then everything else
Curbless requires a structural solution at the floor level — either the subfloor is recessed 1.5 to 2 inches (with the joists below sister-joisted to compensate) or the surrounding bath floor is built up to the shower pan height. We assess this on the estimate visit, tell you which method applies, and quote against the actual structural scope before contract signing. We do not promise curbless and then deliver a 1/2-inch cosmetic threshold that defeats the wheelchair purpose.
Grab-bar blocking at 3 heights during framing — always
Even if you have not committed to bar positions, we install 2x6 or 2x8 horizontal blocking inside the wet wall at three heights during framing: vertical-entry grab bar height, horizontal back-wall grab bar height, and bench-edge bar height. The cost during framing is 20 minutes of carpenter labor; the cost of opening tile later to add blocking is thousands. We do this on every curbless job regardless of which bars you have ordered, because aging-in-place needs change over time.
ADA Section 609 grab bars, pull-tested before hand-off
Every grab bar we install is ADA-rated stainless steel (250-pound static load any direction per ADA Section 609) backed into the structural blocking from framing. Each bar gets pull-tested with the installer's full body weight before we leave — lateral load, downward load, hang from it. The pull-test is the verification at hand-off; we will not declare a bar done without it. The cheap suction-cup bars sold for travel are not a substitute and we will not install them.
ADA-compliant mixer, handheld + fixed head, accessible from outside the shower
The ADA-compliant mixer uses a lever handle (operable with a closed fist, not a knob requiring grip) and is positioned so the controls are reachable from outside the shower (so a caregiver can adjust the temperature before the user enters). The handheld shower head goes on a slide bar or a 60-inch hose so a seated user can shower seated. The fixed shower head is positioned at standard height for ambulatory use. Both heads, one mixer.
Licensed plumber on the drain relocation + insured, background-checked, 30-day workmanship + 2-year tile/pan warranty
The drain relocation from center-of-alcove to linear-drain-at-the-back-wall is more involved than a standard center-drain conversion, and it requires a Washington L&I licensed plumbing contractor per RCW 18.106. We subcontract the drain work and the final fixture trim to a licensed plumber; they pull the Seattle DCI permit under their license. Every Handis carpenter carries liability insurance and clears background screening. 30-day workmanship guarantee on finishes; 2-year warranty on tile-and-pan. The licensed plumber warrants their portion separately under their own license terms. All warranties in writing at project close.
Estimate
Tell us the bath layout, the floor structure (second-story over basement, on-slab, etc.), the user's accessibility needs (wheelchair vs walker vs ambulatory with grab bars), the desired grab-bar positions, and any other ADA preferences (comfort-height toilet, additional fixtures). We send back a clear estimate and a project timeline.
Customer Reviews
Tub to curbless shower (ADA accessibility) reviews from real Handis customers.
Curbless ADA conversion for my dad moving in with us. The team assessed the second-story floor first (the bath sits over the kitchen — they sister-joisted from the kitchen ceiling to allow the recess) and installed grab-bar blocking during framing at three heights even though we had only committed to two bars. Single-plane slope to a Schluter Kerdi-Line at the back wall, ADA lever mixer, handheld on a slide bar so dad can shower seated. Twelve working days. The frameless glass panel was the cleanest curbless install I have seen.
We started thinking about aging-in-place after my mom had a fall in her old shower. Booked the curbless build with three grab bars (entry vertical, back-wall horizontal long-grip, bench-edge angled), a 12-inch deep tile bench, comfort-height toilet, and frameless glass. The team built the bench framing inside the waterproof envelope so the bench tile gets the same membrane as the pan — no leak path through the bench seat. Mom has not had a near-miss in two years.
My husband uses a wheelchair part-time after a back surgery. The standard curbless was actually not enough — we needed a wider opening too. Handis widened the entry to 36 inches by re-framing the door wall (we had to give up a closet to do it but it was worth it), installed the linear drain along the back wall, and put grab bars at three positions. The barrier-free transition extends out under the bath floor tile for two feet so a wheelchair rolling out does not catch any edge.
1956 brick rancher in Magnolia, the bath had been re-done in 2003 with a standard tub. We did the curbless conversion with the porcelain large-format walls, slip-resistant porcelain mosaic floor at DCOF 0.51 (the tech actually showed me the spec sheet), and the licensed plumber handled the drain relocation from the original alcove center to the linear position at the back wall. Eleven working days. Permits pulled by the plumber, inspection passed first try.
My in-laws are moving into the in-law unit we built on our property. The curbless conversion was the biggest accessibility upgrade we needed. Handis came in, looked at the on-slab floor, said the recess was not going to work without a major slab cut and recommended the surrounding floor build-up approach instead. Tile floor in the rest of the bath is now 1.5 inches higher than it was, the shower pan sits flush, and the transition is true zero-threshold. They were upfront on the trade-offs at the estimate visit.
Frequently Asked Questions
Common questions about tub to curbless shower (ADA accessibility) conversion — pricing, timeline, floor structure, ADA standards, and what to expect.