http://www.johnbridge.com/vbulletin/showthread.php?t=91369. If you continue to use this site we will assume that you are happy with it. We are trying to lay slatetile in an entryway. The back side of the drywall fails and it is just as bad or worse than if it had an issue on the tile side. Its a water-resistant membrane used for tiles and paver coverings. Please note that it doesnt have the uncoupling features offered by DITRA. Mark the slope or high point on the walls. In high moisture areas, you can imagine that it is very important to consider this water-resistant feature and functionality so that it will help your projects be more complete. Im thinking the epoxy route is the way to go. Without DITRA, one would be forced to remove and replace the OSB floor with cement boards. I will heed that advice. DITRA performs all these functions while still providing adequate support/load distribution for the tile covering. Waterproofing Corners: Schluter-KERDI-KERECK, 1. Ditra can be installed over a variety of subfloors including concrete, plywood, OSB and radiant heated floors. Tile has been successfully installed for thousands of years by incorporating an uncoupling layer, or forgiving shear interface, within the tile assembly. How Do I Get Rid Of Creeping Charlie And Creeping Jenny. PVA white glue, Acryl 60, weldwood, the list goes on and one.Any tile supplier will have something. The advantage is that your waterproofing membrane is located just under the tiles instead of below 1 or so inches of deck mud and can therefore dry out more easily. Schlter-KERDI-BOARD is simply cut to size with a utility knife. Kgphoto Veteran Contributor Join Date: Jun 2004 Location: Los Angeles, CA The back side of the drywall fails and it is just as bad or worse than if it had an issue on the tile side. I would prefer to seal the KBRS corner seat with Kerdi. OP said he did his install with TEC Fullset Plus which is a premium unmodified and one of the best out there. Something which would consume a lot of time and money. Once it starts to get stiff, it will go off quickly. Bring all of these elements together using the profiles and fasteners specifically designed for KERDI-BOARD assemblies. You can now lay the DITRA over the thinset. With KERDI-BOARD, you can build custom vanities, shelving units, bathtub surrounds, free-standing partition walls, kitchen islands, and so much more. The KERDI-BOARD will protect the ceiling from both water and vapor penetration. Thanks Kevin. Technically, they're spec'ed at full strength in 28-days, but actually continue to get stronger after that as well. Schluter-Systems requires the use of Schluter SET , ALL-SET , FAST-SET, or an unmodified thin-set mortar meeting Can I use a premixed thin-set mortar to install Schluter-KERDI and tile in my shower? While the detail images below demonstrate options for KERDI-DRAIN, please note that raising the bathroom floor is also possible with KERDI-LINE. The simple answer is yes. Point drain with integrated bonding flange. ;). Designed specifically for ceramic tile and dimension stone installations, DITRA serves as an uncoupling layer, waterproofing membrane, and vapor management layer that accommodates moisture from beneath the tile covering. A couple of questions: What color grout are you planning to use? 7. Generally, Schluter-SET, Schluter-ALL-SET, Schluter-FAST-SET, or unmodified thin-set mortar is used. It's pretty easy to resize pics with this utility. That's what it was designed to be applied over in most applications, but I'd use 3/4" ply for the seating area. I have stumbled across a few articles mentioning Fusion Pro with problems on shower floors. Using a Prefabricated Shower Tray and Ramp. And, I am not against trying something new. DITRA and DITRA-XL provide uncoupling to prevent cracked tile and grout. On the surface, OSB may look fragile. Jobsite Saw PRO has a wider table, a new dust-control port, and a more versatile fence, along with the same reliable safety mechanism included in all SawStop tablesaws. Manufacturers generally recommend that the deflection of the subfloor system be limited to no more than span/360 under total load. from what I first gathered the problem was with grout cracking. Is there a product you would recommend? It'll help if you'll keep all your project questions on one thread so folks can see what you're working on and what's been previously asked and answered. (Explained). "Did the article get this detail grotesquely wrong?". KERDI is 8-mil thick and has a water vapor permeance of 0.90 perms, when tested according to ASTM E96, using Procedure E at 90% relative humidity. Yes. KERDI shall be separated at existing expansion, structural, and flexible edge joints. Further, DITRA performs all these functions while still providing adequate support/load distribution for the tile covering. Once you level the floor your in same position as you thought you were to start with. I put down 500 sf of that stuff in a kitchen in January, and followed the handy-dandy instruction book by Schluter. Thanks Kevin. For tile installations using the thin-bed method, apply Schluter-SET, Schluter-ALL-SET, Schluter-FAST-SET, or unmodified thin-set mortar directly to the exposed KERDI surface and install the tiles, ensuring full coverage. Waterproofing corners Schluter-KERDI-KERECK. Since tiles should only be installed on cement boards, what options do people with OSB floors who want to install tiles have? Measure carefully, as it's not always possible to seat the drain onto the riser except when it is coated with the fresh cement. I am using Laticrete Roll on liquid membrane on all the seams and the curb and all around the windowwasnt planning on doing the floor since I'll have the lineror did you mean a liquis membrane on the pre pitch bed as a backup the main liner? No, the KERDI membrane does not have a front/back to it. Once the entire membranewith seams, corners, and connectionshas been completely bonded, and therefore waterproofed, the covering may be applied. A quality unmodified thinset should be used and mixed with a latex additive. Kerdi is all about drywall. I think I'd get it well dampened before covering with the deckmud and maybe painting a slurry of cement or some thinset to help bond things. Can you tile over Kerdi membrane? I'm not so sure any of this makes a difference? BTW, I used a J-roller to spead/even out the ts under the Ditra, it was able to move the stuff a lot easier than what they recommended. Yes, I'm moving the drain to the center. The back side of the drywall fails and it is just as bad or worse than if it had an issue on the tile side. Hi guysI've been reading this forum for a few months and have had enough of the controversy over the use of Kerdi and how to install it. Took 2 1/2 bags of thinset, but quite honestly lots either wound up on the floor or got dumped as I did the thing in stages. bags at Lowe's that you can get for less than the cost of a 50lb bag. Kerdi200/20M covers 215 sq. Not good. KERDI-BOARD, a multifunctional waterproof building panel, gives you more control over your tile installation project by providing you with the means to simply and easily create ideal substrates for tile. For showers and bathtub surrounds, KERDI must be carried to the height of the showerhead at minimum What size notched trowel should I use to install Schluter-KERDI? KERDI-BOARD is one of my favorite waterproofing boards because it's light, easy to cut and has lines on it for aligning the screws. Plus, get an extra 20% off with code GIFT20, Fine Homebuilding Issue #313 Online Highlights, The Fine Homebuilding Interview: James Metoyer, 10 Steps to Install Crown Molding on Cabinets, Choosing the Right Construction Tape for the Job, Expert insights on techniques and principles. Made of polyethylene, DITRA also serves as a waterproofing layer that protects moisture-sensitive substrates, such as plywood/OSB. >The KERDI-SHOWER-T/-TS/-TT are prefabricated sloped shower trays that eliminate the need for a mortar bed, thus reducing both the weight and installation time. 5. Then fill in the rest and slope it to the drain. Very important points Jadnashua has pointed out. Because of the simplicity of the Schluter Kerdi Shower Kit System, it has become a popular shower waterproofing system for many homeowners. To install Kerdi Membrane, start by applying Schulter ALL-SET mortar (or similar) to your cement board substrate using a 1/4 x 3/16 V-Notch Trowel. vBulletin v3.7.4, Copyright 2000-2023, Jelsoft Enterprises Ltd. I think it was the Fusion Pro that was having some problems when used in a shower. Kerdi Trouble - Testing it, have concerns. It is not necessary to tape the joints between drywall panels before installing KERDI. In jobsite conditions and over a long time, who knows. The material is equally suitable for creating level substrates in floor renovation projects e.g. Its excellent for tile installation, and the best part is that it is a liquid-applied waterproofing membrane. As far as bonding goes, no sweat. I would not use a liquid membrane over a Kerdi tray. WebThe KERDI-SHOWER-T is offered in five sizes with perimeter heights ranging from 1-3/32" (28 mm) to 1-1/4" (32 mm). As an alternative to KERDISEAL- PS/-MV, KERDI-FIX or other suitable sealant can be used to seal pipe protrusions and protect moisturesensitive solid backing panels at the mixing valve. Feel free to move it if necessary. Likewise take a grinder to any high spots. vBulletin v3.7.4, Copyright 2000-2023, Jelsoft Enterprises Ltd. The Latest Innovations That Are Driving The Vehicle Industry Forward. Furthermore, the maximum on-center spacing for the screws and washers is 12 inches. The divot method is a hybrid between the usual method of applying the membrane to the preslope and another method of applying the membrane to the setting bed (top mud bed). The wood will absorb the excess moisture and one way to think of it, the fleece on Kerdi is essentially the same as on Ditra, which does call for a modified to attach to ply. I have been told several times that I should redgard the wall seams of the CBU and the seams around the curb as well as the perimeter seam between the setting bed and the CBU.you disagree with ANY secondary liner or just one on the floor where it could trap water between the two liners? How Do I Get Through The Dark Night Of The Soul? DITRA is a polyethylene membrane with a grid structure of square cavities, each cut back in a dovetail configuration, and an anchoring fleece laminated to the underside. Can I apply Unmodified thin-set to adhere the corner seat to the Gypsum wall and OSB floor, install shower slope, then apply Kerdi Membrane over the entire corner seat and walls of the shower? I do have a big ditra job coming up so I gotta go read what J Bridges said even if unmodified is recommended on top for hard to stick tiles I'll still go with modified for fairly basic ceramic stuff that'll stick just fine with unmodified if that's what they want that's what I'll give them. A.Sean Gerolimatos, technical services manager for Schluter Systems, responds: With a few exceptions, unmodified thinset mortar is required for setting ceramic and stone tile over Kerdi membranes (800/472-4588, www.schluter.com ), as well as for bonding overlapped seams and connections to Kerdi drains. Become a member and get instant access to thousands of videos, how-tos, tool reviews, and design features. Therefore, its best to use unmodified thinset when working with an impervious installation membrane like Prodeso for installing radiant floor heating . Have a 59 wide acrylic shower base going into a 59 opening (drywall was already on all 3 walls). No. KERDI was developed as a If the seam is nice, you could use some clear epoxy and essentially butt them together - just make sure you've leveled them really well. We are very concerned about any moisture at all getting into the OSB. KERDI was developed as a waterproofing membrane to be used in conjunction with ceramic and stone tile coverings. And I have been elected to be the one. a buddy said J Bridges is now saying he uses modified on top and underneath too. California Specification 01350 is referenced by various green building standards and rating systems. Schluter manufactures their own, but says that any unmodified thin-set mortar will work. No wait time is required. We use cookies to ensure that we give you the best experience on our website. So if you pre-treated the backs you just ruined the corner. No. For complete installation guidelines and warranty criteria for KERDI in showers, steam showers, and bathtub surrounds or KERDI-DS in steam rooms , please download the Schluter- Systems Shower System Installation Handbook and view the installation videos available below. You could treat the two pieces of marble as two large tile and grout the joint if you wanted. The KERDI-SHOWER-TS features an off-center drain placement and is 1-1/2" (38 mm) high. Do I need to start over or can I simply repair the hole? Either will work to anchor the foam pan. A water test is a quality control check performed on any shower installation before setting tile. A fully waterproof assembly is easily achieved by sealing seams and fastener penetrations with KERDI-BAND. All KERDI components and tiles must be installed using an unmodified thin-set mortar meeting ANSI A118. The Kerdi system is installed using thin-set mortar. Danny if youre worried about sweating the fittings. look into pex and compression rings if codes permit in your local. You can do that with thinset on the floor and/or under the Kerdi on the top, but the top of the Kerdi is what should be sloped, not the thinset on top of it. If you cannot or do not wish to recess the floor or use a ramp, the use of additional materials to raise the bathroom floor is another option. No gypsum levelers ! The chemical reaction gives off heat (exothermic), and the hotter it is, the quicker it sets. over expansion joints or construction joints. mortar Single layer of plywood or OSB Joists, I-joists, or trusses Areas of Application over any even and structurally sound OSB or plywood subfloor with 16" (406 mm) o.c. 1. 1 Can you put Kerdi membrane over plywood? This includes dirt and dust. So, it is safe to install DITRA over OSB. 4. Kerdi is a sheet-applied polyethylene waterproofing membrane and vapor retarder. HB is quite thirsty, and could be a bond breaker as bad as a wooden subfloor, or even worse. and since the plastic did absorb any moisture . it did cure as quick and the "excess" moisture could screw up the grout. Wait 24 hours after the membrane (i.e., Schluter-KERDI-BAND and Schluter-KERDI) installation is complete to allow for the final set of the mortar and to ensure waterproof performance of the assembly at seams and connections before water testing. You only need a pair of scissors to cut the DITRA uncoupling membrane. It's easier to get things level when applied thicker, but that may not be what you want because of height stackups. If so, you haven't done anything wrong. :). The Kerdi system is installed using thin-set mortar. Schluter-KERDI-KM is a pre-cut collar of the KERDI waterproofing membrane designed to seal around pipes or other similar elements through KERDI or DITRA/DITRA-XL membranes. Using the flat side of the trowel, work the thinset on the OSB floor. Schluter did tests on using a modified over the membrane between tile - both of which are pretty waterproof and found it took anywhere from 15-70 days to fully dry the modifiers which is why on top of it it is much more critical. Seems like a decent choice when no other is readily available. Its essential to use the recommended products to avoid disasters. Henry makes one called liquid backerboard that is designed to get to a feather edge over OSB or ply (I'm sure on ply, double-check over OSB). Quite a few people on this site have used versabond. I would just prime with a latrex bonding agent, let it dry 'till tacky and go for it. You have a plastic moisture barrier behind the walls, and a PVC liner under the floor. I think cx is right. Schluter -DITRA and DITRA-XL are specifically designed for ceramic and stone tile installations. The only time I've used Ultraflex with a Schluter product is when I adhere Ditra to a plywood substrate, if you put Ditra over a SLC you need to go back to unmodified. It shouldnt be too thin or too thick. About 1/4" off with a 6 ft. Level. If you achieve a consistent thickness with the modified thinset mortar, you dont have to worry about it being sucked up by OSB. Using KERDI-BOARD to build walls over stud framing in wet areas is an efficient alternative to using gypsum board. Is your existing OSB in the alcove dead level in both directions? Waterproofing strip seals abutting joints of membranes and building panels, Waterproof, multifunctional tile substrate and building panel, Point drain with integrated bonding flange, Bonded waterproofing and vapor-retardant membrane, Single-component sealing and bonding compound, Contact us: 888-472-4588 Tiles moved.Went to try and pry out now unlevel tiles and 'voila', they just lifted right out. Royce,do you like the TEC better than Kerabond? The use of really cold water might give you an extra minute or two. It only needs about 1/8" to achieve the 1/4"/foot value. "I am the master of my fate, I am the captain of my soul." 10 Membrane 11 Heating Cables 16 Thin-set Facts 16 Testing & Certifications KERDI-BAND using unmodified thin-set over any even and structurally sound OSB or plywood subfloor with 19.2" (488 mm) o.c. DITRA should be used over OSB floors in areas where you wish to tile. Your saving a lot of money by doing it yourself instead of hiring it done. Schluter-KERDI is a pliable sheet-applied waterproofing membrane and vapor-retarder designed for the direct application of tile. Thanks again Robert. Yes. Latex-modified mortars must dry for the polymers to coalesce and form a hard Why should I use the Schluter-Shower System? Schluter-KERDI-FLEX is a flexible polyethylene waterproofing strip used to seal movement joints over DITRA in specialty applications where large movements are expected, i.e. Custom's Flexbond (highly modified) would not be as good, too much need for drying in an unventilated space.Bill. The 10-in. Will OSB Suck Moisture from the Mortar Used to Install DITRA? Once you install KERDI over the drywall panels, they will be completely protected from the water and vapor in your tiled shower. Yes. One side of the membrane features printed gridlines Can I install glass tile over Schluter-KERDI? Great product. Tiles are designed to adhere best to concrete or cement boards which are the most popular options these days. You can use one to work the DITRA into the thinset. Thanks Chris. Hey Jim, one last question. 2. Kerdi eliminates water damage which can lead to mold and mildew. Invictus, by Henley. Due to its thin perimeter height, the KERDI-SHOWER-TT is an ideal choice. The plan is to redguard over all of it. Schluter-Systems does not recommend the use of premixed thin-set mortars (mastics/adhesives) in any KERDI installation. CEMENT based only !!!!! It means "Greenboard" can still be used in bathrooms (and other areas), it just cannot be used as a backer for tile in a shower or tub surround. If working with a wood subfloor, you can build up the rest of the subfloor by installing either a 5/8" or 3/4" plywood/OSB panel on top of the wood subfloor along with DITRA or another Schluter-Systems uncoupling membrane. Can I install Kerdi membrane over Hardibacker? say that I expect to be a life-long subscriber." With the KERDI-SHOWER-TT thin shower tray on a wood subfloor, you can build up the rest of the bathroom floor by installing either a 5/8 or 3/4 plywood/OSB KERDI-BOARD building panels are quick and easy to install and allow you to achieve substrates that are flat, level, plumb, and square. The KERDI-SHOWER-T is offered in five sizes with perimeter heights ranging from 1-3/32" (28 mm) to 1-1/4" (32 mm). Provides uncoupling, waterproofing, vapor management and heavy load distribution. Best to get the 7/8" OSB to match. Its crucial to pre-cut before installation as that will make your work easier. Possibly. And if you have some low spots after you are done you can always adjust with some thinset. Since thin-set mortar works over almost any substrate, the Kerdi system can be used over drywall, plywood, or the various cement boards mentioned above. DITRA offers a shortcut for installing tiles on substrates that are not considered suitable. There are different types of OSB, from OSB1 to OSB3. Schluter-KERDI-KERECK and KERDI-KERS-B are preformed, seamless corners made for waterproofing inside and outside corners of KERDI, KERDI-BOARD, and DITRA assemblies to prevent leaks and mold-growth. KERDI has been evaluated according to the Standard Method for the Testing and Evaluation of Volatile Organic Chemical Emissions from Indoor Sources Using Environmental Chambers, Version 1.1 for California Specification 01350 and found to comply with the VOC requirements. If that is the case, I am assuming Versabond is ok? Silicone or sand caulk in the corners since its a change of plain. Neither one absorbs moisture and both offer some interesting features (glow in the dark! They can easily be cut to size with a utility knife, or may be extended with dry-pack mortar. Can you install Kerdi board directly on studs? Mark the coverage of the Kerdi on the hardieboard. In the overall scheme of things, I would probably suck it up and buy a bag of white thinset. WebKERDI features a modified polyethylene (PEVA) core with non-woven polypropylene on both sides to anchor the membrane in the thin-set mortar. Over a concrete subfloor use a bonded mortar bed of appropriate thickness to build up the rest of the bathroom floor. A minimum of nominal plywood or OSB thickness installed 1) The preslope is tapered at a 1/4" per foot pitch. The type of bonding mortar used to apply KERDI must be suitable for the substrate and must penetrate and engage the membrane fleece. You can also use Schluter-KERDI, a membrane made of polyethylene. Sorry about that. I am nearing completion of my tile shower project. Even though OSB3 can be used in humid areas. houndzilla I think I was looking for someone to verify what I knew to be the answerha ha. Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. The time between liquid and starting to set can be quite abrupt. 2. Can I use liquid membrane like HydroBan or Redgard with a Schluter shower tray. I never had done drypack before and it was pretty simple to do. Cover the joints with KERDI-FLEX. With the KERDI-SHOWER-TT thin shower tray on a wood subfloor, you can build up the rest of the bathroom floor by installing either a 5/8" or 3/4" plywood/OSB panel on top of the wood subfloor along with DITRA or another Schluter-Systems uncoupling membrane. This seems to contradict what I Why is it so easy to peel it off the wall today? Do I need an uncoupling membrane on plywood? All shower trays feature integrated KERDI waterproofing and are designed specifically to integrate with the KERDI-DRAIN. A bunch of products can be used over an OSB floor. We are trying to lay slate tile in an entryway. How do I know if the thin-set mortar is modified or unmodified? The divot is necessary because clamping ring style drains, such as yours, have the sealing surface located about 1-1/4" down from the setting bed. Some suggest marble is not recommended for showers. Building mud screeds along that line is fairly simple, just pile a row of mud against the wall so it covers the line by about an inch, then using a straight board, press the mud down until you can just see the line again. DITRA-XL is 5/16 (7 mm)-thick and allows for ceramic tile application over single layer plywood/OSB subfloors on joists spaced at 24 (610 mm) o.c. IMPORTANT: Stud spacing exceeding 16" requires the placement of additional studs. I need to run to lowes today anyways. Yes,Kerdi can be installed on drywall or cement board. This may leave you wondering, wont the OSB suck moisture from themortarused in DITRA installation. Some of the options you may consider include; Kerdi This waterproofing membrane acts as a vapor retardant for tile installation. How do you prepare OSB subfloor for tile? The nominal 5/16 (8mm) thickness minimizes tile assembly thickness. If you intend to install another type of floor, such as hardwood, there is no need for DITRA. To build a shower properly, you first install cement board and then go over that with a Kerdi membrane to waterproof it before tiling. A-holes. Not sure what controversy there is to installing Kerdi. The Laticrete 255 DITRA, on the other hand, is an uncoupling membrane used for tile installation. Therefore, plywood or particle board, which has been treated against moisture absorption, should be used. They can dimple if you put point pressure on it. KERDI is ideal for use in tiled showers, bathtub surrounds, residential steam showers, and other tile applications in wet areas. The gridlines printed on the surface are helpful for neat and quick installation. The thickness of the tile assembly is minimized by using Ditra, "I am the master of my fate, I am the captain of my soul." Go with a masonry bench or look into the better bench or nobel bench. Start your subscription today and save up to 70%. Follow the Wood Underlayment installation guidelines as found in the Schluter-DITRA or Schluter-DITRA-HEAT Installation Handbooks for fastening guidelines. The system can also be customized with floor heating cables to create a warm, luxurious tile floor. For inside and outside corners, adhere pre-formed KERDI-KERECK-F corners. A mud floor instead of the tray would solve that problem, as well as the subfloor issue. Glass tiles are unique products and may require special consideration. The material is physiologically safe and does not require special disposal. J. Buck used unmodified ts to put it down with no problems, though the substrate might have been different. Not so good side to side. The seam in the middle I would think could be whichever you prefer. Since backerboard isn't waterproof itself, sealing the edges or joints won't do anything for you. Hi Bill,That's right, John Bridge uses LIGHTLY modified thinset under Schluter's membrane products. Once its flat, please turn to the V-notched side and trowel it so that you see grooves on the surface. Invictus, by Henley. They are OK as long as they aren't rolling a piano over it this month. Does unmodified thinset stick to plywood? Uncoupling membrane prevents cracked tile and grout. Multifunctional building panels: Schluter-KERDI-BOARD, 2. and be done with it. As for the seams, they can be sealed with Kerdi Band. That can be mitigated by using DITRAs waterproofing capabilities. We use cookies to ensure that we give you the best experience on our website. There is never 'the answer' but 'an answer'. I should make that my tagline. I will be using Ditraset to install the kerdi on the walls and to set the tiles. Thanks Kevin. Support answered that they recommend modified. Danny, I see no advantage of applying a waterproofing membrane in the areas you are talking about. Thinset to just outside those coverage marks with the flat side of the trowel, then come back and give it a quick comb with the notched side of the trowel. How thick is Kerdi membrane with thinset? Tiles were 12x12.Let's not confuse the issue with facts! Ideally I would like a fold down slatted wood seat mounted on the wall. What material is used behind shower walls? Air bubbles must be avoided. Support answered that they recommend modified. I have two pieces of marble that will need to be cut to create a shower curb cap (2-42" pieces to join to fill a 60" curb). Danny, this the same master bath you have an earlier thread about? However if installed on drywall it is only protecting one side. Portland cement-based unmodified thin-set mortars are dependent on the presence of moisture for hydration in order to gain strength. Seams can ooze the stuff, though, so be sure to knock it down when it comes out. Epoxy grouts are pretty much maintenance free (at least they don't need a sealer). Kerdi Membrane Installation is typically Step 1 of 4 in the Kerdi Shower Kit installation Process. Calculate all your membrane requirements for your project. I am out of level less than 1/4" from side to side and I'm going over OSB. Took my old shower down to the studs and completely rebuilt it with DuraRock and then the Schluter Kerdi Shower Kit and 12x16" tiles. Hey every group has to have one. What Does It Mean When A Guy Spreads His Legs In Front Of You? This allows the cement to properly hydrate, resulting in Schluter-KERDI-SEAL-PS and Schluter-KERDI-SEAL-MV are prefabricated waterproofing seals with over-molded rubber gaskets designed for protrusions through KERDI, DITRA, or DITRA-XL membranes and protect moisture-sensitive backing panels at the mixing valve. Use unmodified thin set to You really need to read the installation and spec sheets very carefully. Finally getting ready to finish my shower project. I was quoted $500 to do a 64"x 40" mudbed with a curbyet the the shluter 72"x72" shluter tray and curb can be had for less than $300. I'm good front to back (32" depth). Work your way aound the shower, placing and packing mud as you go. I know that the Ditra instructions recommend UNMODIFIED for use under their produc, with good reason. - M.K. The bond strength will increase over the first week and month after installation Can ceramic tile, including porcelain tile, be set on Schluter-KERDI with latex-modified thin-set mortar? KERDI-BOARD can be installed both vertically and horizontally using the screws and washers in our hardware assortment. Makes it real simple to install and when done right good for 50 years. Now that you know DITRA can be used over OSB, its time to learn how to do it. What about if you prime/seal the osb first. Continuing Education for Architects & Designers.