Shower Pan Troubleshooting, Repairs, and Reliable Installation Techniques

Transcription

1 Shower Pan Troubleshooting, Repairs, and Reliable Installation Techniques Doug Horgan, (703) The inside of a shower gets as much rain as the rainiest jungle on the planet. The tiniest of flaws can result in the tear-out and rebuild of an entire $15,000 shower. Ensuring leak-proof showers is one of the most important jobs for us, both to take care of our clients, and in our own interest.

2 Our standard double layer construction Summary: Our standard system is built in five steps. 1. Pre-slope 2. Standard plumber s bi-level shower drain & pan, often installed by tile company 3. Mud bed, durock on walls and curb 4. Second waterproofing layer, typically Kerdi 5. Tile & grout (Each step is detailed below.)

3 Details: Below are more detailed explanations of the five steps. 1. Pre-slope: there are two typical ways to slope below the plumber s pan (so water on the pan will drain down to the drain weep holes). i. Plywood, very well supported (use shims, glue, screws): ii. Drypack mortar. Typically applied over felt. Any masonry/concrete material should do.

4 2. Standard drain and pan: a. Standard bi-level shower drain is required. Bi-level means the water can leave in two ways; the grate at the top, and weep holes at the bottom: There are four pieces to a standard shower drain: i. Bottom flange, which sits on/in the floor and connects to the drain pipe. The plumber s pan material sits on top of the bottom flange. ii. Clamp ring, which bolts down to the bottom flange and pinches the plumber s pan. The weep holes molded into the bottom of the clamp ring (on top of the plumber s pan) must be kept open. iii. The grate holder ( beauty ring ), threaded so you can adjust the height of the grate to match the thickness of the mud bed and tile. iv. The grate itself, which is attached to the grate holder with screws. b. Some slot drains work with a standard bi-level drain body. The slot trough replaces parts iii. and iv. (the beauty ring grate holder, and the grate) in a regular PVC drain. Installation is similar to a regular drain. An example is ACO Quartz. (Other slot drains are not bi-level, and use a single-layer

5 installation rather than our double-layer installation method.) c. Plumber s shower pan material: i. Prefer CPE material (Chlorinated Polyethylene, examples: Noble Chloraloy; Oatey CPE) over PVC material (Polyvinyl Chloride, examples: Oatey PVC, IPS, Compotite) because it should last longer and has fewer phthalates (stinky softener chemicals, which leach out). ii. A heat gun helps with the folding process. iii. Get the directions for the material being used; ensure materials and directions for drain, glue, seams, corner dams, etc. are correct match for the liner material. d. Glue pan material to top of drain bottom flange, per instructions of the pan material company: i. PVC pans from Oatey and IPS use special shower pan PVC glue (Oatey calls theirs X-15) ii. PVC pans from Compotite use butyl sealant iii. CPE pans from Noble use either NobleWeld 100 glue or NobleSealant 150 caulk iv. Note: the bottom flange and clamp ring must be clean and flat, and come as a matched set; do not use one company s clamp with another s bottom flange. v. Note: most shower pans in the real world have not been glued to the bottom flange (that is, they were not installed per instructions). They usually work fine. However, there s no good reason not to follow the directions and use the recommended glue or sealant. vi. Note: usually the company specifies that the liner be cut minimally for the bolt penetrations, that is, a small hole for each bolt rather than a large hole or slot.

6 vii. NOTE: DO NOT GLUE THE WEEP HOLES SHUT. No sealant between top of pan, and bottom of clamp ring. e. If seams are needed, adhere with special glue (not regular pipe glue) per manufacturer s directions.

7 f. Use pre-formed corners ( corner dams at ends of curb, benches, any outside corners. Curbs normally have four outside corners and require four patches. g. Cover benches, use corner patches at ends

8 h. Suggestion: recess folded corners into wall, so durock can lay flat. Either space between studs, or notches in stud face. See shower pan directions. i. Suggestion: block between studs to help hold pan material up. Hold blocks 1/8-1/4 back from faces of studs so folded pan material doesn t push out cement board. j. Flood test by filling with water up to curb level and leaving for at least 24 hours. k. Directions for some common brands of shower pan material: i. Oatey shower liner: ii. IPS shower liner: iii. Noble shower liner:

9 3. Mud bed and CBU: a. A setting bed of drypack mortar is installed on top of the plumber s pan. i. Mud bed 3/4 to 1-1/4 thick with expanded lath reinforcement per TCNA. ii. Install mud as soon as possible after inspection, to protect pan from damage by drywall guys, etc. Hint: get your own drain plug, leave water in shower pan until tile company arrives to install the mud bed, no one will step in the water, so the pan is protected. iii. Use a handful of pea stone to maintain open drainage at drain weeps. Alternatives: tile spacers, manufactured device (example, Noble ring), dimple-sheet membrane. b. CBU/wall board: i. Install #15 felt or 4-6 mil plastic "Water Resistive Barrier (WRB)" on the walls, behind the wall board, in front of the plumber's pan. 1. Any water that leaks through the walls runs into the pan. 2. Use felt instead of plastic on exterior walls in our mixed humid climate (Washington, DC). 3. OK to omit where waterproofing is used all the way up the inside face of the wall board, for example in a steam shower or single-layer system (example, Schluter Kerdi-System). ii. Only use cement board products such as Durock, Perma-Base, Wonder Board, or Hardie Backer. Gypsum materials like Dens-guard must be sealed on all edges, apparently can be damaged by water, and are a questionable choice for a wet location, in my opinion. iii. Hardie Backer must be kept out of mud bed, it absorbs water and falls apart. Suggest keeping durock out if possible. iv. No fasteners through pan material below curb level inside of shower. Minimize fasteners at curb, bench, etc. v. Mud bed and fiberglass tape can be used to hold durock on inside of curb and front of bench. vi. Fasten per instructions from manufacturer. Regular drywall screws are not OK.

10 4. Second waterproofing layer a. Cover vulnerable areas (anything horizontal) from the floor level up, especially including the curb & bench areas, with sheet waterproofing (examples: Schluter Kerdi, Laticrete Hydro Ban Sheet Membrane, Noble Wall). b. Curb ends are typical failure points. Wood movement always cracks the grout, allowing water in. c. Waterproofing must extend outside the shower and down onto the floor to protect the curb, framing, and drywall. Waterproofing doesn t cover the outer corner of this curb. The shower on the left suffered water damage later, and had to be rebuilt. The one on the right is also inadequate, but was fixed before we finished it. Typical curb-end damage. Tile and grout often leak at the corners. d. Similarly, finishes (drywall, wood trim) outside the door opening are vulnerable to water soaking through the stone/tile/grout and must be protected. These doorways are well protected at the curb ends. Even the edge of the drywall is waterproofed.

11 Extend waterproofing over the edge of drywall as far as possible (as far as hidden by tile or trim around door), use vinyl corner bead to avoid rust (waterproofing can be run between drywall and corner bead). e. Tub decks that extend into showers: i. should be waterproofed a long way out from the shower. Water will seep into the grout and under the tile, even past where the glass sits. ii. Consider a slope or short curb built into the tub deck, so water is directed back into the shower. f. Sheet Waterproofing: Schluter Kerdi, Laticrete Hydro Ban Sheet Membrane, Noble Wall Seal, NobleSeal TS are sheet waterproofing applied with thinset. While they are expensive, they are quick and reliable. Get the directions and follow them! i. Some key Schluter Kerdi installation points: 1. Use non-modified Schluter thinset for Kerdi installation. Acrylic-modified thinset voids the Schluter warranty. (Note: most thinset is acrylic-modified.) 2. 2 overlaps mandatory 3. Use pre-formed corners on every outside corner

12 4. When used as secondary waterproofing, cover any horizontal surface (examples: curb, bench, half-walls, tub deck extended into shower, shampoo niches); AND vertically down from any of these surfaces to the floor. 5. Schluter Kerdi directions: us/en_us/membranes/waterproofing-(kerdi)/schluter%c2%ae-kerdi-&-kerdi- DS/p/KERDI g. Liquid applied waterproofing (examples: Laticrete 925 or Hydro Ban, Custom Red Gard, Mapei Aqua Defense) are reliable and easy to work over complex shapes. However, they typically require the CBU seams be taped with fiberglass tape and thinset, and two or more coats of liquid. No pinholes are acceptable. Dry time, and wait time before water testing, can extend the application process to three full days. Read directions. i. Laticrete Hydro-Ban directions: ii. Mapei Aqua Defense: iii. Custom Red Gard: h. Covering the shower floor with waterproofing is optional, in this double-layer system. i. Not recommended with liquid-applied waterproofing because the floor mud tends to stay wet and re-emulsify the waterproofing. ii. If the floor is covered, how does water get into the drain? (You will have to leave a path to the lower weeps, or drill weeps into the upper drain piece.) iii. If electric floor heat is being used, we must waterproof the floor. Consider using a singlelayer approach, or be sure to add weeps to the drain for the upper waterproofing.

13 Non-preferred single layer method. (Required for most slot drains or for Schluter Shower System.) Summary: This system omits the regular plumber s pan and bi-level drain, and uses a special drain. Waterproofing runs just behind the tile, all the way from the drain, across the floor, and up the walls to above the shower head. Instead of five layers, there are only three: 1. Pre-slope, typically a mud bed 2. Special non-bi-level drain, installed per instructions; Waterproofing layer, typically sheet material. 3. Tile & grout Details: 1. Sloped mud bed should have reinforcement in it (per TCNA). Foam slope kits are a possibility, but be careful to follow directions. Very small or large tiles can t be used on foam slope kits, for example. 2. Drain must be a type designed to work with the waterproofing system. a. Read and follow instructions. b. Do not cut off parts of the drain flange! Even if a rep tells you to! (Get it in writing!) c. Schluter and Noble make accessory parts to convert a standard bi-level drain into a singlelayer application. 3. No redundant second layer in this system, so membrane must be applied without flaws. a. 2 overlaps mandatory b. Must cover entire shower from shower head down, not halfway up wall c. Use special accessories to integrate valves, pipes, etc.; leaks at valves must be prevented, with just one layer of waterproofing it is out of the system and into the framing. d. Use pre-formed corners wherever required e. Recommend non-modified Schluter-brand thinset for Kerdi installation

14 A. Other tips Escutcheons: Sometimes they leak. a. Best to caulk the top and sides. b. Always leave a gap at the bottom for water to drain out. This escutcheon filled up with water because it was caulked all the way around (the water entered where the handle comes through the escutcheon). Cutting out the bottom caulking, and sealing the valve to the tile, stopped the leak into the wall. c. Accessory flanges should help a lot, use when possible but they are hard to find in the exact right size. Corners/trim: water gets into the jambs and curbs, adjacent material will be wet. a. Waterproofing can be run to cover the edge of drywall; run behind corner bead and use vinyl corner bead.

15 b. Other types of vinyl bead can be used to protect drywall and joint compound from directly contacting tile/stone. c. Use stone or ceramic material to trim out opening; less vulnerable to water. Run Kerdi behind to protect drywall. d. Wood trim, use waterproofing to separate from tile, stone, thinset, and grout. Backprime wood to protect more. e. Mark height of base and width of casing material (whether tile, stone, or wood), and run waterproofing out of shower as far as will be covered.