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Shower Pan & Waterproofing (Schluter / Kerdi / Wedi)

Handis builds the continuous waterproofing system behind tile that a shower actually needs — Schluter KERDI sheet membrane, KERDI-Board panels, or the full Wedi Fundo foam-pan system — from $2,500 for a foam-tray pan in a standard 3-by-4 alcove up to $6,000 for a curbless walk-in with a custom mortar-bed pan and a full Wedi enclosure. Most fifteen-year shower failures we are called to repair trace to the same single mistake — cement board treated as waterproofing behind the tile. It is not. Cement board is dimensionally stable under moisture exposure (it does not swell or crumble the way drywall does) but water passes straight through it. A real shower pan is a foam tray bonded to the substrate or a sloped mortar bed protected by a continuous sheet membrane, tied with seam tape at every change-of-plane, wrapped at the curb, sealed at the drain flange, and flood-tested for 24 hours before a single tile goes on the wall. Active in-wall plumbing supply or drain leaks discovered during demo route to a licensed Washington L&I plumber FIRST; Handis returns to rebuild the substrate, pan, and membrane after the licensed trade closes their portion.

Shower pan and waterproofing image — Schluter KERDI orange sheet membrane freshly bonded to cement-board substrate inside an opened-up Seattle alcove shower, the foam-tray pan set and sloped to a KERDI-DRAIN, KERDI-Band seam tape running every inside corner, a roll of KERDI-Band and a notched trowel staged on a clean folded towel.

Service

Wide editorial photo of a Schluter KERDI-Shower-Tray foam pan freshly set in a Seattle alcove and sloped to a KERDI-DRAIN, the orange KERDI sheet membrane bonded up the walls with KERDI-Band running every inside corner, a notched trowel and a roll of KERDI-Band on a clean folded towel, plastic-zip wall sealing the bathroom doorway from the rest of the home.
Process

How a Shower Pan & Waterproofing Build Works

Seven sequential steps across a 3-to-5 working-day project — demo, framing prep, substrate, pan, membrane, drain, flood test. The actual sequence we follow on every Schluter, KERDI, or Wedi build.

Step 1/7

Demo Existing Pan and Wall Substrate

Existing pan (acrylic, fiberglass, mortar bed, or failed Kerdi) lifted out. Wall substrate (drywall, greenboard, cement board, or failed Kerdi-Board) removed up to the membrane termination point. Active in-wall plumbing leaks discovered during demo route to a licensed Washington L&I plumber FIRST; Handis returns after their portion closes.

Step 2/7

Framing Prep, Blocking, Drain Rough-In Check

Stud spacing verified for substrate fastener pattern (16 inches on center for KERDI-Board, blocking at the bench and niche locations). Drain rough-in inspected for height and centerline match to the pan. Sub-floor inspected with a moisture meter and patched where wet OSB or plywood is found. Joist sister-up where a top edge has rotted.

Step 3/7

Substrate Set — Cement Board or KERDI-Board

Substrate set to the framing. Cement board (Hardibacker, Durock, USG Tile Backer) fastened to studs with cement-board screws at six inches on center, joints taped with alkali-resistant mesh tape and thinset. KERDI-Board panels set with KERDI-Fix sealant and panel washers, joints sealed with KERDI-Band. Substrate flat to a quarter inch in 10 feet.

Step 4/7

Pan Set — Foam Tray or Custom Mortar Bed

Foam-tray pan (Schluter KERDI-Shower-Tray or Wedi Fundo) set in thinset on the sub-floor, leveled to the drain, manufacturer-spec slope at one-quarter inch per foot. Custom mortar-bed pan mixed on site, trowelled to slope, cured 24 to 48 hours before membrane. Drain assembly tested for fit on the pan before any bonding.

Step 5/7

Membrane — KERDI Sheet, KERDI-Band Seams, Drain Bond

KERDI sheet bonded to substrate with unmodified thinset, rolled flat with a deck roller, KERDI-Band bedded at every inside corner and wall-to-pan transition. Drain flange sandwiched in the membrane with KERDI-DRAIN sealant. KERDI-Board installs use the same KERDI-Band pattern at panel joints. Wedi installs use Subliner tape and Wedi 320 sealant in the same pattern.

Step 6/7

Curb Wrap, Niche Tie-In, Bench Tie-In

Curb wrapped with KERDI sheet on all three exposed faces and tied into the pan membrane and the wall membrane with KERDI-Band. Niche framed with KERDI-Board and seamed with KERDI-Band. Bench (where in scope) framed with KERDI-Board and seamed in the same pattern. No bare cement board exposed to water anywhere in the enclosure.

Step 7/7

24-Hour Flood Test Before Tile

Drain blocked with an inflatable test plug, pan filled to within an inch of the curb height (or to the lowest threshold for a curbless layout), water level marked. Held for 24 hours. Re-checked at 24 hours — pan loses no water, or we open the seam tape and rebuild the section that failed. Flood-test photos in the sign-off file before tile install starts.

Pricing

Shower Pan & Waterproofing Pricing

Final pricing depends on the pan footprint, the membrane system (KERDI sheet vs KERDI-Board vs Wedi), whether a custom mortar-bed pan is required, the niche and bench scope, and the drain location relative to existing rough-in. Active in-wall plumbing leak discovered during demo routes to a licensed Washington L&I plumber; their portion passes through transparently with the line item named. Tile install is a separate scope priced per square foot of finish. Request a free estimate for an accurate quote.

Send us a phone photo of the existing pan and the drain location — we will quote the membrane system before booking.

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Why Seattle Homeowners Book Handis for Shower Pan & Waterproofing
Trust

Why Seattle Homeowners Book Handis for Shower Pan & Waterproofing

A waterproofing build is the part of a shower that nobody sees and everybody pays for either way — either at install for $3,500 done right, or at the fifteen-year mark for $9,000 in demo, mold remediation, sub-floor patch, and rebuild. The reason fifteen-year shower failures cluster on a single failure mode is that the building code for a shower pan was written for a paper-faced PVC liner under a mortar bed — a pre-Schluter, pre-KERDI, pre-Wedi standard that passes inspection and lasts twelve to twenty years before the PVC seam at the corner cold-weld lets go and the mortar bed wicks pan-floor water into the sub-floor. The bonded-membrane systems that came out of Germany in the 1980s (Schluter Kerdi) and the early 2000s (Wedi) solved that failure mode and have a thirty-year-and-counting field track record. Handis builds to the bonded-membrane standard on every shower we touch.

Estimate

Tell us the bathroom (master, guest, hall), the pan footprint (3-by-4 alcove, 4-by-4 walk-in, 5-by-5 curbless, or measure tell us the rough inches), the drain location (center, off-center, or linear at the curb), whether you have a bench or a niche in scope, and whether the shower is going to be steam-rated. Send phone photos of the existing pan and the drain area if you can. We quote membrane system, drain, and any sub-floor or framing prep before booking. Tile install is a separate line on the quote.

Service cost estimate illustration
Reviews

Customer Reviews

Shower pan and waterproofing reviews from real Handis customers.

Original 1998 mortar-bed pan in the master had been weeping into the sub-floor for at least three years before we caught the mildew bloom in the closet on the other side of the wall. Handis demoed the pan, found the PVC liner had cold-weld failed at the corner exactly where everyone said it would, set a Schluter KERDI-Shower-Tray foam pan, tiled the walls and floor over a full KERDI sheet membrane, flood-tested for 24 hours before the tile went on. Closet wall is bone dry six months later.

Daniel and Robin R., KERDI-Shower-Tray Pan Replacement

Curbless walk-in shower in a new master suite addition. Wedi Fundo Riolito linear-drain pan, full Wedi Building Panel walls, Wedi Subliner tape at every corner. The flood test ran for 24 hours, the foreman showed me the water-level marker and the re-check photo before the tile crew came in. The shower has been in use for almost a year. No mildew at the corners, no movement at the drain.

Patrick and Ellen H., Curbless Wedi Walk-In

Standard 3-by-4 alcove shower in our 1990s spec build. Pan was original and starting to leak around the drain. Handis demoed and built a Schluter KERDI-Shower-Tray with a KERDI-DRAIN center drain in two days, plus the full sheet membrane on the walls. They actually walked me through the seam tape pattern at the inside corners before they tiled. Eight months later, every grout joint still clean, no movement anywhere.

Wes and Anna B., KERDI Sheet Membrane (Alcove)

Mid-demo Handis found an active drip from a copper supply line behind the shower valve. They stopped, called their vetted Washington L&I plumber, the plumber was on site the next morning, replaced the supply nipple with a SharkBite fitting and pressure-tested. Handis came back, finished the KERDI-Board substrate and the pan. The plumber's portion was named on the quote line by line, no surprises.

Erica and Mark T., KERDI-Board with Plumber Sub

Custom mortar-bed pan in a 4-by-6 walk-in shower where the drain location did not match any foam-tray pan on the market. Site-mixed dry-pack, sloped one-quarter inch per foot to the drain, cured 48 hours, full KERDI sheet on the cured bed. Flood test held water for the full 24 hours. The bathroom finished clean and the shower has been in service for seven months without a single grout-line issue.

Justin and Brianna T., Custom Mortar-Bed Pan
FAQ

Frequently Asked Questions

Common questions about Handis shower pan and waterproofing builds — system selection, flood testing, drain bonding, scope, and timing.

How much does a shower pan and waterproofing build cost?
A standard Schluter KERDI-Shower-Tray foam pan in a 3-by-4 alcove starts at $2,500 for the membrane-and-pan scope, with tile install priced separately by square foot. A Wedi Fundo foam pan in the same footprint runs $2,800. A full KERDI sheet system on walls and pan in a 4-by-4 walk-in runs $3,500. KERDI-Board panels on a 4-by-5 walk-in run $4,500. A custom mortar-bed pan with KERDI sheet on a 4-by-5 layout runs $5,000. A curbless or ADA pan with a full Wedi enclosure in a 5-by-5 layout runs $6,000. You get a written estimate before any work begins with the membrane system, the pan style, the drain assembly, the niche and bench scope, and any plumber-sub portion named line by line.
What is the difference between Schluter KERDI sheet, KERDI-Board, and Wedi?
Three bonded-membrane systems we install. Schluter KERDI sheet is an orange polyethylene fleece-laminated membrane that bonds to a separate substrate (usually cement board) with unmodified thinset and seams together with KERDI-Band at every corner — the most common pick on retrofit pans and standard alcoves. KERDI-Board is a green extruded-polystyrene panel that replaces the substrate AND the membrane in one product, installed directly to the framing with KERDI-Fix sealant and panel washers — the fastest path on new-construction layouts. Wedi Fundo / Wedi Building Panel is the German equivalent system with its own panel and seam-sealant ecosystem (Wedi Subliner waterproof tape, Wedi 320 sealant). All three are bonded-membrane systems with field track records past twenty years; cement board alone is not.
Why does the drain assembly have to be bonded to the membrane?
A non-bonded drain flange (a flange that sits on top of the substrate and accepts a field-cut hole in the membrane around it) is the second most common shower-leak path after un-taped pan-to-wall corners. Pan-floor water reaches the seam between the membrane and the flange, finds the field-cut edge, and seeps around the drain into the sub-floor below. A bonded-flange assembly (Schluter KERDI-DRAIN, KERDI-LINE, or a Wedi-compatible bonded-flange drain) sandwiches the membrane sheet between the drain flange and a bonding ring sealed with KERDI-DRAIN sealant — the water cannot get around the bonded seal. Every pan we build uses a bonded-flange drain. No exceptions.
What is a flood test and why do you do it before tile?
A flood test is the pre-tile leak check on the finished pan and membrane. We block the drain with an inflatable test plug, fill the pan to within an inch of the curb height (or to the lowest threshold for a curbless layout), mark the water level with a pencil at the start, hold for 24 hours, and re-check the water level at 24 hours. If the pan has lost zero measurable water across the hold, the membrane is sound and tile install proceeds. If the pan has lost any water, we open the seam tape on the suspect section and rebuild before tile goes on. The flood test catches a seam failure before the tile hides it forever. Every pan we build gets one. You see the photos.
Do I need a permit for a shower pan rebuild?
Most shower-pan rebuilds inside the existing wet-area footprint do not require a permit — they are repair-and-replace work on an existing fixture. Permits are required when the work involves moving the drain, moving the valve, changing the rough-in dimensions, structural framing changes (joist work, wall relocation), or any new electrical or HVAC work in the bathroom. The licensed Washington L&I plumber pulls the permit for their portion when in-wall plumbing work is in scope. Handis does not pull plumbing or electrical permits ourselves. We will tell you on the booking call whether your scope crosses into permit territory.
What if you open up the wall and find an active plumbing leak?
We stop and call a licensed Washington L&I plumber as the responsible licensed party for the leak fix. Handis routes to a vetted plumber on the same call, schedules the licensed-sub site visit (usually same-day or next-day on an active leak), and the plumber repairs the supply or drain line. Handis returns for the substrate, pan, and membrane rebuild after the leak fix is signed off and the substrate has dried out (24 to 72 hours of dry-down with a heat-assist dehumidifier where needed). The plumber's invoice is separate from the Handis invoice — both quotes are on the table before any work continues.
How long does a shower pan and waterproofing build take?
A standard alcove pan with a foam tray and KERDI sheet membrane runs 3 to 4 working days from demo to flood-test sign-off, plus the 24-hour flood-test hold. A walk-in shower with a custom mortar-bed pan runs 5 to 6 working days because of the 24-to-48-hour mortar cure before the membrane goes on. A curbless / ADA pan with a Wedi enclosure runs 5 to 7 working days depending on the sub-floor recess scope and the linear-drain install. Tile install on top of the finished pan is a separate scope and adds 3 to 5 working days depending on the tile pattern and the layout. The flood-test hold is the only fixed-duration step you cannot accelerate.
Can I just use cement board behind the tile — why do I need a membrane?
Cement board is dimensionally stable under moisture exposure. That is what it is good at. It does not swell, crumble, or rot the way drywall or greenboard does. But water passes straight through cement board into the framing behind it — the fiberglass-mesh-and-cement composition is porous to water. A shower wall with cement board and no membrane behind the tile is a slow-drip distribution system that wets the framing every shower, every day, for years before the failure becomes visible. The fifteen-year shower failures we are called to repair trace to this single mistake almost without exception. A real shower has a bonded membrane behind the tile, full stop.
Do you cover homes outside Seattle proper?
Yes — most of the Puget Sound region is in service area, from north Seattle and Shoreline through Bellevue, Redmond, Kirkland, Issaquah, Sammamish, Renton, Tukwila, Burien, and south to Federal Way and Auburn. Shower-pan and waterproofing builds on the I-90 corridor (North Bend, Snoqualmie, Cle Elum) and Hood Canal property are covered with a travel premium added to the project price; we will name it on the quote before you sign. Outside that radius we will tell you on the call if the math works.
Is the work guaranteed?
Yes. Handis carries general liability and workers' compensation; every technician has cleared a background screening before the first job. Our one-year project warranty covers the substrate, the pan, the membrane, the seam tape, the drain bond, and the flood-test result — if a seam fails, the flood-test result regresses, or a substrate goes soft inside a year because of our workmanship or prep, we come back and rebuild the affected section at no charge. The Schluter and Wedi manufacturer warranties on the products themselves run longer (Schluter offers a lifetime warranty on KERDI when installed by a trained installer) and we register every build for the manufacturer warranty so you have a paper trail. The licensed-sub portion (any plumbing work) carries its own Washington L&I-trade warranty, also named on the quote so you know whom to call for what.

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