Is Vapor barrier needed behind Durock when using Kerdi membrane?
15 years ago
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- 15 years ago
- 15 years ago
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Durock - Hardi - Wonderboard - Kerdi
Comments (10)Discalimer: I'm clearly no expert . . . It seems to be builders' preference. My tiler was used to doing Durock for commercial applications--stronger, more vandal-proof. I dislike Durock's "crumbly" edges (warranted or not), so I chose Hardibacker instead. It's easy to cut. Unlike Durock, however, Hardi wicks water easily (even though it's "waterproof," it's not vapor-proof, like a Kerdi, Tyvek, or other vapor/water-proof membrane. Hardi just doesn't warp or get damaged by water). That in mind, installed correctly, I'm sure all of the available commercial cementboard products do their job satisfactorily. I did my guest bath in Hardibacker with a Tyvek vapor barrier between the Hardi and the studs. However, in the master bath shower, I really want to do a Kerdi shower. The Kerdi system seems like the best system for no-worry, never-leak membrane systems. The peace of mind will be well worth the $400-$500 in materials cost (which I think is trivial in light of the cost of all the other materials, fixtures, and labor you're about to invest in). Just my novice opinion . . . I'll let the real experts chime in now....See MoreAm not getting the vapor barrier thing, at all?
Comments (20)"He (GC) says that any water wicking through will have no chance to dry out if it becomes trapped by the vapor barrier, and you increase the chances of mold growing between the vapor barrier and cement board. This makes sense to me!' How can mold and mildew form and thrive between poly sheeting and cement board? Mold and mildew need food to survive. That food it cellulose. Cellulose is wood or wood-derived products like paper. Paper facing on kraft-faced insulation, paper facing on drywall, etc. Moisture trapped between a 6-mil poly vapor barrier/drainage plane and the cement backer board has no cellulose in sight, so the green stuff can't thrive. The moisture will eventually dry out back into the bathroom, just as Bill described. No poly vapor barrier? Then when the moisture gets behind the cement board and wets the the kraft paper facing of the insualtion, or the framing, then you get the funky green stuff. Moisture, spores, and food equals the dreaded green funk. It's tough to get your head wrapped around these concepts, but trust me, the way Bill and others have said is correct. Your GC is wrong. He may have good intentions, but he's just uneducated. Building Science is a continually evolving process. Changes to the building code normally lag bulding science by as much as a decade. Sometimes even longer. Too many builders don't learn about or apply changes made to the code until several years after the code has been changed. Many "rotted wall" stories are from having vapor barriers behind greenboard. Trapped water and the paper facing food source on greenboard leads to the dreaded green funk, soon followed by the wetting and rotting of the gypsum core of the greenboard. But who here has been tiling over greenboard? Only the guys who like greenboard because it's cheaper than cement board and easier to cut and hang than cement board. Greenboard was allowed by code as a tile backer in wet areas until January of '06. Yet I've NEVER used it as a tile backer. Doing what's allowed by code isn't always the right way to build. Remember, code is the MINIMUM building standard. In some areas of construction the minimum is good enough. In other areas it's far below. That's why the code evolves. Mongo...See MoreDodged a bullet: no vapor barrier, membrane to go under mud bed
Comments (2)Best thing to do would be to go to Noble's website and read the pdf files on installation. Like most membranes, care needs to be taken when folding the membrane in the corners, at the membrane/drain intersection, how high the membrane goes up the walls, how the membrane drapes over the curb, and where to drive fasteners to attach the membrane to the framing and where to not use fasteners to attach the membrane to the framing. I'd wrote the book for you...but Nobel already has! And they have drawings/pictures! Best of luck with the project, Mongo...See Moredurock was wet when purchased now looks funny
Comments (8)Thanks Mongoct, well the insulation that was there was so dusty dirty from all the demo that I just pulled down the paper part of it and threw it away. Leaving the bulk of the pink insulation behind. I will fill in the empty areas with the new and I will probably have lots left over, so is it ok to just put more insulation over top and then just cut slits in the surface brown paper? Then the durock will go up. Then work on the shower floor I have a stack of 2% styrofoam slope stuff that I have to figure out how to put in (weird shape shower) Drain is at the entry way of shower. Then I have the blue stuff for the shower floor membrane (noble) I am planning to run the product up higher then the recommended 4" I hope I have enough it is going to be very tricky figuring out this end of the project. Any comments/suggestions gladly welcome. I really have to figure out how to post photos it would make things so much easier. TIA...See MoreRelated Professionals
Schenectady Kitchen & Bathroom Designers · Champlin Kitchen & Bathroom Remodelers · Sicklerville Kitchen & Bathroom Remodelers · Greeley Glass & Shower Door Dealers · Saratoga Glass & Shower Door Dealers · Tukwila Glass & Shower Door Dealers · Bon Air Cabinets & Cabinetry · Burr Ridge Cabinets & Cabinetry · Mount Prospect Cabinets & Cabinetry · North New Hyde Park Cabinets & Cabinetry · Prospect Heights Cabinets & Cabinetry · Colorado Springs Window Treatments · Patchogue Window Treatments · St. Louis Window Treatments · Sun Lakes Window Treatments- 15 years ago
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