Custom Curbless / Walk-In Shower
The master remodel where the homeowner is planning to age in place in this house and the new shower has to go in curbless because a one-inch curb at age 78 is the difference between a daily-used shower and a weekly one. The Mercer Island remodel where the design call is the modern wet-room look — no curb, linear drain, large-format porcelain walls reading like slab, frameless glass at the entry. The Capitol Hill condo where the wheelchair-rollover access for an adult child is the requirement and the rest of the bathroom is being designed around that center constraint. The downtown Bellevue penthouse where the architectural intent is the spa-resort wet-room aesthetic and the curbless shower is the center of it. A curbless walk-in shower removes the curb that defined the shower footprint in the traditional design and replaces it with a recessed mortar pan sloped to a linear or trench drain — the surrounding bathroom floor sits at the level the shower pan steps down from, the waterproofing membrane extends beyond the shower footprint into the surrounding floor for splash containment, and a single frameless tempered-glass panel handles the visual separation without a door to swing open. Done right, it lasts 30 years and is the most accessibility-forward shower design available. Done wrong — wrong slope, wrong waterproofing wrap-out, drain undersized for the flow rate — it leaks into the surrounding floor on every use. Handis self-performs every step end to end. From $8,000 for a single-wall walk-in with a mortar pan and a KERDI-LINE linear drain up to $16,000 for a three-wall walk-in with a built-in bench, stone-tile walls, and a curbless mortar pan tied into a custom-cut slab subfloor. The in-wall mixer rough-in and any drain-line relocation sub to a licensed Washington L&I plumber.
Service
How a Custom Curbless Walk-In Shower Build Works
Eight sequential steps from the structural assessment through the final sealer pass — the actual sequence Handis runs on every custom curbless walk-in shower build.
Structural Assessment and Subfloor Plan
Walk the existing bathroom on the booking call and the on-site measurement. Determine whether the subfloor is slab-on-grade (concrete, saw-cut to recess), wood-joist (drop joists or build up surrounding floor), or already recessed (rare on a remodel). Confirm the drain location (existing center vs new linear) and any drain-line relocation work. Quote reflects the structural scope.
Saw-Cut Slab or Joist Drop
Slab-on-grade — saw-cut the existing concrete to the recess depth (typically 2-1/2 to 3 inches), break out the cut, prep for the new pre-pan. Wood-joist — sister new joists at the lower elevation under the shower footprint, cut existing joists to match, install new subfloor at the recessed level. Either way the structural prep is done before any waterproofing.
Mortar-Bed Pan with Single-Direction or Four-Way Slope
Linear-drain pans get a single-direction slope from the entry to the back drain at 1/4 inch per foot. Center-drain pans get four-way slopes from the perimeter to the center. Sloped pre-pan in deck mud over a 40-mil PVC pan liner running 6 inches up the walls. Deck-mud topping cures 24 to 48 hours before the membrane.
Schluter KERDI or Wedi Sheet Membrane on Walls and Pan
Orange KERDI polypropylene-fleece sheet bonded with unmodified thinset to every cement-board wall and the pan topping. KERDI-BAND on every seam and inside corner. KERDI-SEAL-PS at every penetration. KERDI-DRAIN or KERDI-LINE bonding flange tied into the pan membrane. The membrane sits 24 hours.
Membrane Wrap-Out Into the Surrounding Floor
The critical curbless detail — KERDI on the shower walls and pan transitions to Schluter Ditra on the surrounding bathroom floor for at least 12 inches beyond the shower footprint on every side that does not abut a wall. The membrane continuity is uninterrupted. Catches the higher splash a curbless shower generates without exposing the surrounding-floor substrate.
Niche and Bench Wrapped Into the Membrane
Pre-formed KERDI-BOARD niches foamed into stud-bay cut-outs and seam-sealed. Built-in benches framed with treated lumber, cement-boarded, KERDI'd on every face, seat-tiled. Niche floor sloped 1/8 inch to the front for water shedding.
Tile Setting — Large-Format Porcelain or Honed Stone Walls, Mosaic Pan
Walk-in walls in large-format porcelain (12x24 through 24x48 with medium-bed LFT thinset and MLT lippage clips) or honed natural stone (Carrara, Calacatta, travertine, limestone with white Mapei Granirapid thinset and unsanded grout). Pan in penny-round, hex, or matched mosaic for slip resistance and pan-slope follow. Grout matched to design intent. Cures.
Frameless Glass Panel and Final Sealer
Custom-measured frameless tempered-glass panel installed at the entry — 3/8 inch standard, 1/2 inch on larger panels. Two coats of penetrating sealer (TileLab SurfaceGard, Aqua Mix Sealer's Choice Gold for porcelain; Miracle 511 Impregnator for natural stone) after grout cures 24 to 72 hours. Second coat after the first cures 24 hours.
Custom Curbless Walk-In Shower Pricing
Final pricing depends on the subfloor type (slab-on-grade saw-cut vs wood-joist drop or build-up — joist work adds the most variability), the shower footprint, the wall-tile material (large-format porcelain vs natural stone), the niche and bench scope, the drain choice (linear or center), and whether the in-wall mixer is being replaced (licensed-plumber sub). Glass enclosure is line-itemed on every quote as a custom-measured panel. Request a free estimate for an accurate quote.
Tell us the bathroom subfloor type (slab or joist), the shower footprint, the wall-tile material, and the drain preference (linear or center) — we will quote the curbless build with full KERDI wrap-out as standard.
Why Handis for Custom Curbless / Walk-In Showers
A curbless walk-in shower is the project where the difference between a 30-year install and a 10-year one is invisible behind two specific details — the recessed-pan slope and the membrane wrap-out into the surrounding floor. Done wrong, a curbless shower sends water under the surrounding flooring substrate on every use, and the failure mode shows up as a damp spot in the bedroom ceiling below or a soft spot in the bathroom floor outside the shower 18 to 36 months in. Done right, with the slope verified to 1/4 inch per foot in the right direction and the KERDI membrane extending at least 12 inches beyond the shower footprint into a connected Ditra layer on the surrounding floor, a curbless shower outlasts a curbed install. Handis does both details as non-negotiable standard scope on every curbless build. The wrap-out is what makes curbless work; the wrap-out is what most installers cut to save a day.
Estimate
Tell us the bathroom subfloor type (slab-on-grade concrete, wood-frame joist, or unknown — we will check on the measurement), the shower footprint, the wall-tile material preference (large-format porcelain or natural stone), the drain preference (linear at the back or center), the niche and bench scope, whether the in-wall mixer is staying or being replaced, whether the existing drain location stays or relocates, and any accessibility-forward requirements (wheelchair rollover, grab-bar locations, bench dimensions). We send a clear estimate with full KERDI waterproofing and the surrounding-floor wrap-out as standard scope.
Customer Reviews
Recent custom curbless walk-in shower reviews from verified Handis customers.
Curbless walk-in shower in our master remodel. Curbless mortar pan with a linear drain, full Schluter waterproofing tied into the bathroom floor with Ditra on the surrounding-floor wrap-out, large-format porcelain on the walls, frameless glass at the entry. The aging-in-place wheelchair-rollover access we wanted is in there too. Handis sequenced the plumber for the valve cleanly. The whole project finished on the calendar they gave us.
Curbless wet-room walk-in in our Mercer Island remodel — 24x48 porcelain walls reading almost like slabs, a Schluter KERDI-LINE linear drain across the back wall, frameless tempered glass at the entry. Handis did a joist drop under the shower footprint to recess the pan without building up the surrounding floor — preserved the existing baseboard and door swings. The bathroom reads as a spa.
Curbless walk-in on a slab-on-grade downstairs bathroom in our Capitol Hill condo. Handis saw-cut the slab to recess the pan, set the mortar pan with single-direction slope to the linear drain, full KERDI wrap-out into the surrounding floor as Ditra. Honed Carrara walls and a Carrara penny-round mosaic shower floor. The whole bathroom rebuilt around the curbless shower. Eighteen months in, dead-dry surrounding floor and tight seal at the drain.
Wheelchair-accessible curbless shower for our adult child in our Bellevue split-level. Handis worked with the occupational therapist on the bench dimensions, grab-bar locations, and the drain placement that keeps the wheelchair rollover path dry. Built-in bench framed and KERDI-wrapped, large-format porcelain walls, slip-resistant porcelain mosaic floor. The functional requirements were the design driver and the install reads as intentional design, not as compromise.
Curbless walk-in upgrade from a 1990s curbed shower in our 1985 split-level. Handis built up the surrounding floor with a 3/4-inch plywood layer rather than dropping the joists (faster, cheaper, but cost us a 3/4-inch baseboard rework which we knew about up front). Mortar pan, linear drain, full KERDI wrap-out, 18x36 porcelain walls. Eight working days. We saved $1,500 over the joist-drop option because the structural reality of our particular bathroom made the build-up the right call.
Frequently Asked Questions
Common questions about Handis custom curbless walk-in shower builds — structural prep, drain choices, waterproofing wrap-out, accessibility, and pricing.