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.
Service
What Does a Shower Pan & Waterproofing Build Include?
A shower-pan and waterproofing build is the substrate-and-membrane scope that sits between the framing and the tile — covering demo and removal of the existing pan and wall substrate where present, framing prep and blocking for the new pan and any bench or niche, substrate set (cement backer board or Schluter KERDI-Board), the pan itself (Schluter KERDI-Shower-Tray foam pan, Wedi Fundo Ligno or Riolito foam pan, or a custom mortar-bed pan sloped at one-quarter inch per foot to the drain), the continuous waterproofing membrane (Schluter KERDI sheet bonded with unmodified thinset, or KERDI-Board panels installed with KERDI-Fix and washers), seam tape at every inside corner and substrate joint (KERDI-Band or Wedi Subliner), the drain assembly (KERDI-DRAIN, Schluter KERDI-LINE for linear, or a Wedi-compatible bonded-flange drain), curb wrap, niche tie-in if a niche is in scope, and a 24-hour flood test before any tile goes on. From $2,500 for a foam-tray pan in a 3-by-4 alcove up to $6,000 for a curbless walk-in pan with a full Wedi enclosure.
Pan Selection — Foam Tray or Mortar Bed
Foam-tray pans (Schluter KERDI-Shower-Tray, Wedi Fundo Ligno, Wedi Fundo Riolito for linear-drain installs) ship pre-sloped to the drain at one-quarter inch per foot — set them in thinset on the substrate, bond the membrane lip to the wall membrane, and the pan is done in a single day. Custom mortar-bed pans (a dry-pack mortar bed mixed on site and trowelled to a one-quarter-inch-per-foot slope) are required when the drain location does not match a standard tray, when the pan footprint is non-rectangular, or when a curbless ADA layout calls for a recessed sub-floor. Mortar-bed pans cure 24 to 48 hours before the membrane goes on; foam-tray pans accept the membrane the same day. We recommend on the booking call based on the layout you describe.
Membrane — Schluter KERDI Sheet, KERDI-Board, or Wedi System
Three membrane systems we install. KERDI sheet membrane is the orange polyethylene fleece-laminated sheet that bonds to the substrate with unmodified thinset and seams together with KERDI-Band at every corner and joint — the most common pick on retrofit pans and standard alcoves. KERDI-Board is the green extruded-polystyrene panel that replaces the substrate AND the membrane in one product — installed directly to the framing with KERDI-Fix sealant and washers, seamed with KERDI-Band, the fastest path on a new-construction layout. Wedi Fundo / Wedi Building Panel is the German foam-and-fiberglass-mesh system that is structurally similar to KERDI-Board with its own panel and seam-sealant ecosystem (Wedi Subliner waterproof tape, Wedi 320 sealant). We are factory-trained on Schluter and we install Wedi on request — the system matched to the pan and the layout.
Drain — Bonded-Flange Assembly, KERDI-DRAIN or KERDI-LINE
The drain assembly has to bond to the waterproofing membrane, not float through it. We install Schluter KERDI-DRAIN (center-drain or square grate) or Schluter KERDI-LINE (linear drain at the curb or against the wall) with the membrane sheet sandwiched between the drain flange and the bonding flange, sealed with KERDI-DRAIN sealant. Wedi-system installs use the Wedi Riolito linear drain or the Wedi-compatible bonded-flange drain in the same sandwich pattern. The drain assembly accounts for the most common shower-leak path in a fifteen-year shower failure — a non-bonded drain flange that lets pan-floor water seep around the drain into the sub-floor. We do not install non-bonded flanges.
Seam Tape at Every Change-of-Plane
Every inside corner, every wall-to-pan transition, every substrate joint gets KERDI-Band (or Wedi Subliner on Wedi systems) bedded into thinset and rolled flat. The fleece-to-thinset bond is what keeps the seam waterproof under hydrostatic load. Skipped seam tape at the pan-to-wall corner is the single most common shower failure path on a DIY or low-bid install. Every corner of every pan we build gets seam tape — no exceptions.
Flood Test Before Tile
Every Handis shower pan gets a flood test before tile goes on the wall — 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), held for 24 hours, water level marked at start and re-checked at 24 hours. The pan loses no water across the 24-hour hold or we open the seam tape and rebuild the section that failed. You see the flood-test photos with the sign-off before tile install starts.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
Factory-trained on Schluter, installer on Wedi
Our lead tile setter holds Schluter Systems installer training (KERDI sheet, KERDI-Board, KERDI-DRAIN, KERDI-LINE, KERDI-Band seaming). We install Wedi systems on request and on full-bath specifications that call for it. Either system is built to the manufacturer's spec sheet, not to a we-have-always-done-it-this-way shortcut.
Real waterproofing — not cement board treated as waterproofing
Cement board (Hardibacker, Durock, USG Tile Backer) is dimensionally stable under moisture exposure. It is not waterproof. Water passes straight through it into the framing behind. Every Handis shower gets a continuous bonded membrane (KERDI sheet, KERDI-Board, or Wedi panel) tied at every change-of-plane with seam tape. You see the membrane on a walk-through before tile goes on the wall. You sign off on it.
Bonded-flange drain assembly — no exception
The drain assembly bonds to the waterproofing membrane. KERDI-DRAIN, KERDI-LINE, and Wedi-compatible bonded-flange drains sandwich the membrane sheet between the drain flange and the bonding ring, sealed with KERDI-DRAIN sealant. We do not install non-bonded drain flanges with field-cut KERDI patches around them; that is the second-most-common path of failure after un-taped seams and we will not build to it.
Flood test on every pan, photographed for sign-off
Every pan gets a 24-hour flood test before tile goes on the wall. Drain plugged, pan filled to the curb height (or the lowest threshold for a curbless layout), water level marked at start, re-checked at 24 hours. Pan loses no water across the hold, or we open the seam tape and rebuild. Flood-test photos go in the sign-off file with the dated sticker.
Honest plumber handoff when the leak source is in-wall
An active in-wall supply line leak, a pinhole in the copper above the shower ceiling, a slow drain leak inside the wall — any of these means a licensed Washington L&I plumber is the responsible licensed party for the leak fix. Handis routes to a vetted plumber on the same call, schedules the licensed-sub site visit, and returns for the substrate, pan, and membrane rebuild after their portion is signed off. We do not do in-wall plumbing supply or drain repairs. The plumber's portion is named on the quote line by line.
One-year project warranty on the membrane system
The Handis project warranty on every shower-pan and waterproofing build is one year — if a seam fails, a 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 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.
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.
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.
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.
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.
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.
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.
Frequently Asked Questions
Common questions about Handis shower pan and waterproofing builds — system selection, flood testing, drain bonding, scope, and timing.