Thanks for the quick reply and all the good information. I was unaware of the Kerdi system but just checked it out on-line and am very interested.

This is quite new to me but if I understand you correctly I need to float a concrete floor sloped at 1/4" per foot for drainage, placing the Kerdi material directly on top of the newly floated concrete, followed by thin set, tile and grout? No other steps?

Kerdi seems to create the exact barrier I'm looking for. Given that it is waterproof, couldn't I build the shower out of drywall and the apply Kerdi directly to the drywall (i.e., studs, drywall, Kerdi, thinset, tile, grout)? Would drywall be strong enough behind tile for support, or am I not understanding the function Kerdi serves?

Lastly, where is the best place to purchase Kerdi and any tips for its application?

Thanks again, I appreciate all the help.

Bill, - all this came after a tile nightmare - see below - my thinking was to paint the redgard over the liner seams overlappying thickly so any water getting through the tile and grout would sheet to the liner and run to the drain. The previous shower didn't have any membrane at all - it was just mudded. And actually the "general contractor" I hired to do the job said he had done tons of tile jobs "travertine and marble etc. etc. in LA/San Diego area" (I should have called some of those references) - then halfway through the job he just didn't show up - when I finally reached him by using my cell phone that had a different area code (he never returned any of my or DH calls left on his cell and home phone) he said I could "hire someone else for the amount of money I owed him" - I told him I didn't own him any more money till the job was completed. (I had paid him half already and I bought all the materials) Supposedly he was getting a "6 figure job in Florida" and I was left with a real mess - even had to rip out some tiles around the caddy and window because he started his tile run at the edge of the shower and when the tile reached the window and caddy there would have been only a 3/4 inch of tile at the caddy and window - we have 12x12 tiles in there. We made the best of the situation by being creative and fixing a lot of his mistakes. I had actually gotten local references for other work he had done in this area - and he had done some stucco repair for us on another part of our house and had done fine. After he quit, I checked his contractor's license in the computer and his license was expired. As has been said by lots of folks here - now that I am looking back through other posts, just because someone is a general contractor - doesn't mean they can do tile in a correct or an esthetically pleasing way. I think our tile job will be ok - I feel the redgard and fibermesh overlapped at the seams will create an impervious membrane. But next time I will check the work every step of the way - DH had initially told me to "leave him alone - the job will turn out fine" - some of the things he was doing didn't seem quite right - he didn't know anything about the rubber liner ??? red flag - and wanted to use mastic - I told him not to and why - then he sneaked mastic in my house and used it on the floor tile - that didn't dry for 4 days. After he quit we pulled up all that tile (the mastic still hadn't dried) and cleaned it off and were able to reuse it. Now I know to trust my instincts and the valuable advice of you and others on this forum.

This is quite new to me but if I understand you correctly I need to float a concrete floor sloped at 1/4" per foot for drainage, placing the Kerdi material directly on top of the newly floated concrete, followed by thin set, tile and grout? No other steps?

That's somwhat simplified, but nope-- that's it. :-) One thing you need to be aware of-- in order for this system to work, you NEED to use their drain. It has a halo around it that the membrane gets affixed to, thereby giving a complete seal to the drain.

springvalegardens-- I know this is all in retrospect, but this statement-- some of the things he was doing didn't seem quite right - he didn't know anything about the rubber liner ??? red flag wasn't a red flag. That by itself is enough to throw the guy off the job, lock stock and barrel, right then and there. Do not pass go, do not collect 200.00. That's enough to make it perfectly clear that he has absolutely no idea of what he's doing.

Bill, you are correct - but I had already paid him half of the money up front - which he said was customary. He had asked for half of the money up front when doing the stucco job and he did complete that several months earlier to our satisfaction. After he started doing things in the shower I thought weren't quite right, I started checking on all of his work, looking in this forum, asking questions, etc. - to be sure he did it correctly. I knew that another tile contractor would not want to follow what he did - they would want to rip everything out and start from fresh because they wouldn't want their reputation based upon someone else's work - and we don't have an unlimited amount of money to pay twice - we are on a very tight budget. In fact I called several tile people and either they were too busy or they said they didn't want to finish a job that was already started. Looking back I see that he probably has done the same thing to a lot of people - gets some of the money up front and then only does a little work and then asks for more money, etc and then quits and the homeowner is left holding the bag. He actually asked me for $100 more and I said no I would not pay him any more money until the job was done - and that was when he didn't show up the next day or the next day, etc and we called and called. I think this is what is called a "con" - then they leave town and no one can find them. I will be making a complaint to the contractor's board and hopefully they can catch up with the guy - so other trusting and unsuspecting homeowners do not have the same "con" pulled on them.

I have heard that other supposed contractor's who have done this have been put in jail - and they should be. I live in a small town and I am telling everyone I know about this person - so if he ever comes back - people will know what he does.

I am building a steam shower upstairs in my house. Right now this is the plan.
6mil sheat over 3/4 floor and up the walls about 6 inches. 1 1/2 to 2 inch sloped TYype S masin mix floor. Then 40 mil shower pan linerglues down and around the drain. Next another type S mix 1 to 1 1/2 inches over shower pan with wire mesh installed in it. Lastly tile set on thinset.
Does that sound good enough?

Second part for the walls I was using the 6mil sheet up and over lapping on teh walls followed by a Hardie board. Should I redguard the Hardie board (corners and walls)before I sert teh tile on teh walls?

Last part what about the bench area. Can I install shower pan liner then hardie baord and tile right over this or should I use Redguard on the seat as well?

Thanks for the time.

Help!

I have a leak under our wood floors AGAIN! ...and have now replaced the wood floors twice. We're about to go for a third time!!! A leak detection company came in the first two times and said that the water is coming from outside the house so we installed a french drain the first time and remortared the chimney (the second time), which were the proposed solutions. I have had pressure tests each time and they come up clean, so now the thinking is that I have a ground water leak that is coming up through the slab. The latest recommendation is to raize the floor again, and use Red Guard as the membrane and then either put wood or tile down. Any suggestions?

If you've got ground water coming through the slab, then you need some other solution than waterproofing the slab!! Believe me when I tell you-- water will not be stopped. You'll build up what's called hydrostatic pressure until the waterproofing membrane gives way, and then you'll be right back to square one. You need to get an engineer in there to figure out a way to redirect the flow of groundwater, if that's what it really is. if that IS the problem, I'd be curious as to what redirected the flow in the first place to start coming through your slab.

OK _ here my situation _ I have gotten as many asnwswers as there are people. I have an 800 sg ft interior space joist 2 x 12 16 and 12 " oc. 3/4 advantec with radiant tubing on top./ I am going to pout a 3000 psi concrete and then finsih . OK so now onto isolaation membrae or crack isolation. WIll redguard serve as an appropriate crack isolation system? I know there is Ditra but at $2.75 a sq ft I might as well just put down a wood floor. OK let me drive ya nuts. Local tile guys here are telling me put down vinyl at 0.10 sq ft glue it to the concrete and you will have a very sturdy and very cheap crack isolation membrane

Mike

If you shortcut now, you'll pay for it later. As for Ditra at 2.75 a foot, that's robbery. Go to tile-experts.com . I think you'll be very pleasantly surprised..... even AFTER shipping.

We had a spillage from our bathroom on to our carpet, we took the carpet and underlay up and now just have bare concrete that kind of smells a little musty/moldy, if that is the right word. We have tried to make sure it is completely dry and now we have purchased Red guard sealer. Will this work to get rid and seal off future musty/moldy smells? What would you advise when using this product? We plan to put in a new wood floor once we have figured this out.

coco-- you may want to wash that concrete down with bleach, first. The only thing that you'll accomplish with the Redgard is that moisture will not transmit thru it. If there's nold or mildew growing in or on the concrete, you want to kill it before covering it up.

I was told by a licensed contractor (in CA) that redguard is the choice for waterproofing a fountain before applying tile. Would you agree? If not, what is the ideal choice to waterproof (and handle any small cracks that may occur in the concrete) a fountain??
Thanks! :)

I would NOT agree. My choice would be one of two-- Either Laticrete's 9235 or Hydroment's Ultraset. This is contingient on the water fountain being in an area where freeze/ thaw issues aren't a problem. :-)

Hello Bill or other expert,

I live up in rainy British Columbia in a rather unusual house build of stone masonry and concrete. There is a rooftop deck - which is made of a concrete slab, and about 4 years ago slate tile was installed on to this deck over top of redguard which had been trowel-ed on, supposedly according to the instructions (I was not present during any of this) Lost story short...the majority of the tiles have a hollow sound to them, and I've been able to lift a number of them by hand with very little effort...and it was wet under the tiles...At this point I'm looking for a permanent solution. I intend to remove all of the slate tile, and redo the whole deck - possibly using Ditra as the isolation/membrane this time around. But what I'm wondering about is - do I need to try to remove the redguard which is still (mostly) adhering to the slab? The original mortar didn't seem to bond to it at all.. Also, I'm hoping to increase the grade on the patio/roof in order to increase drainage...is there any way short of pouring another slab (which would need to be another 4 inches at the thinnest and therefore not an option) The deck/roof is basically 17' x 18'...would I be insane to try and make a mortar bed for that size?...would it be too prone to cracking or other problems?

Thanks for any insight you can give!

One way or the other, the deck needs to be sloped a minimum of 1/4" per foot. It sounds like one of your problems is that water sat under the tile, but on top of the Redgard, froze, and popped the tiles loose. Although some will agree with using Ditra outside, I'm not a big advocate of it. Schluter even says it's okay-- so long as you use the Kerdi-band on the seams. My preference would be for another product put out by the Noble Company called Nobledeck. it's made SPECIFICALLY for exterior applications. it's a tough membrane that goes on basically the same way as Kerdi, and like Kerdi, tile can be set directly over it. Also like Kerdi, it only adds about 1/16" to the subfloor height.

Here is a link that might be useful: Nobledeck (3rd item down the page)

Thank you Bill, In my web browsing I was starting to wonder if Noble was the better product for my situation. So, would the best way to go about this be: to remove the old redguard (in some areas it's removing itself anyway) and then use deckmud or concrete to get the slope, then use Noble deck under the tiles and thinset? Or would it be to strip the redguard, put a whole new layer of redguard down, then add the slope and put the noble deck etc down? Also, what is generally the best way to add a slope to an existing concrete slab over an occupied area that will result in the least additional height being added? ie how thin can either deck mud or concrete for this purpose be?

Thanks again, it's great to have access to some real experts online.

remove the old redguard (in some areas it's removing itself anyway) and then use deckmud or concrete to get the slope, then use Noble deck under the tiles and thinset

hatsa the one. :-)

I am currently taking quotes to tile my entire basement floor which is a concrete walkout basement. Approximately 650 sq. feet. This home was built in 1980 and although the floor does have minor cracks throughout it's area, these cracks are nothing major and have not appeared to change over time. I am finding that opinions vary by contractor. One says he recommends covering the whole floor with a thin rubberized membrane, while another claims that to be overkill and only recommends using Redguard on the more prevalent cracks only. As you can imagine, there's a substantial cost difference as well. My objective is to get it done right and to guarantee a longterm, crack free tile installation. Please advise me as I'm reading mixed reviews regarding Redguard and find it being used more for moisture barriers more so than for crack isolation. Any suggestions?

Okay, let me put it this way. BOTH contractors are right.... SO LONG as none of the cracks have one side higher than the other. The Redgard should be enough, but no matter what product you discuss, the sheet membranes will outperform roll on or trowel on products every time.

Good afternoon, I am not sure if you answered this previously as I tried to read through all of the posts. I am redoing my shower and just have a few questions. Currently done, I have a pre-sloping concrete slab with rubber membrane(up about 12 inches on the wall and over the curb) towards the clamping drain. I have the backerboard about 1.5 inches above the rubber membrane currently. I am soon about to poor the second cement layer which will also be slightly sloped and where the tile will be layed. 2 questions. First, I do not have a vapor barrier behind the CBU, I plan on using Redgard or blue seal, this should be applied to the entire cbu and especially in the corners and use fiberglass mesh, correct? Also, which is the main question, if I use either of these, I can use laticrete mega bond with latex adative (from lowes) to adhere the tiles to the wall (directly to the redgard or blue seal), correct? Thank you.

First, I do not have a vapor barrier behind the CBU, I plan on using Redgard or blue seal, this should be applied to the entire cbu and especially in the corners and use fiberglass mesh, correct?

Correct. In the corners, also use thinset to fill any gaps before applying the membrane.

if I use either of these, I can use laticrete mega bond with latex adative (from lowes) to adhere the tiles to the wall (directly to the redgard or blue seal), correct?

Correct.

I LOVE it when posters can answer their own questions!! :-)

Bill, thanks for the quick reply. In the shower, currently there is no vapor barrier as stated before, if I did have a vapor barrier, would I need the redgard? (I read a few places that both is bad as it could lock the moister between the two layers.) Also, if I just used the vapor barrier, is 15 lb roof paper sufficient? Thanks again.

No, and yes. :-)

(no you wouldn't need the Redgard, and yes the 15 pound tar paper would be sufficient. Matter of fact, it's recommended.)

Hello, I am hoping for some help with a moisture problem in our home.

We live Central California, in a 20 yr old home with a slab foundation We have noticed dampness and now dark/mold spots on top of our carpet in some areas. We have checked the walls and pipes and there are no cracks or leaks.

We have been told that it is moisture coming up from the gound through the slab and that we need to pull up the carpet/lino and put in a moisture barrier THEN we can put in new carpet and tile/lino and won't have to worry about it any more. I was also told we could just put a barrier over the lino (without pulling it up)and that it would be ok to tile/lino over it.

I have searched online and found out about DITRA, and today I was told about Redguard by a Home Depot employee.

I am somewhat confused about which product would solve our problem. I read that membrane type barriers will
out-perform the trowel/roll on types, but was told that they really won't "solve the problem" and that they will just trap the moisture between the slab and membrane leading to mold/mildew problems. Is this right?

I really want to do this right so that we can do it once and be done with it.

Any insight would be MUCH appreciated!

Shary

Moisture will not be trapped. It'll follow the path of least resistance, just like electricity, in this case, that being out to the edge of the slab. I understand the whole trapping issue-- it stands to reason that moisture would be a constant directly under the Ditra. However, if you trowel apply a membrane on, like Redgard or 9235, then the same argument could be used about moisture IN the slab. Mold could also start there, as well. But just like directly below the Ditra, it won't.

I removed an old fiberglass tub and one piece surround and have installed a new tub. I hung green board above the new tub and want to install a tile surround. I was told by a friend to put tar paper over the green board and mud over that. After the mud dries I can put thinset and install my tile. However when I went to Home Depot to buy the stuff they recommended to install the tar paper on top of the green board, then 1/2" hardiboard, then thinset and tape hardiboard seems, then apply redgard over all of the hardiboard, then thinset, then tile. If I go the hardiboard route do I need the tar paper behind it or can I just use redgard on top? Or can I just put tar paper behind the Haridiboard, thinset and tape the seems, and then put the tile? What is best method (i really don't want to float all the walls with mud).

Okay. This is the very first time I've ever heard of it being recommended to someone to DIY their own mudset walls! 90% of the tile PROS I know can't do that!! LMAO

A couple of comments concerning the Hardi. First, there's no need for the greenboard. Take that right down. ALl you need is 1/2" Hardiboard, and you're good to go. Secondly, either or, between the tar paper or the Redgard, BUT NOT BOTH. You can either staple tar paper up to the studs behind the Hardi, or you can put the Hardi up and paint it with Redgard. Either one will work just as well to meet requirements for a wet area. But doing both will create what's called a "moisture sandwich" where moisture can get trapped and cause a terrific breeding ground for mold and mildew to grow.

My bathroom walls, including the shower area, are covered with Georgia-Pacific DensArmor Plus. I have a Kohler shower pan in place and I am planning on puting tile or travertine on the walls in the shower area. Which would be a good way to go; Redgard-thinset-tile, Zinsser Gardz-thinset-tile or Kerdi-thinset-tile? Or none of the above.

The only one of the above I'd recommend would be Kerdi over the DAP, but I'd call Schluter tech or check out the Schluter website to see if it's a recommended substrate. I'd think it would be since Kerdi can go over regular drywall.

With DAP not being an approved tile backer in wet areas, I wouldn't recommend RedGuard over DAP.

I haven't used Kilz's product so I won't comment on that.

Mongo

I'm finishing my basement and would like to tile the floor, walls & ceiling of the bathroom. The shower stall would have the same tile on the walls, but an acrylic base (pan) w/glass doors. Currently the room is bare studs on 16" centers, cement floor & roughed-in plumbing w/no floor drain. Since the room will be used by tenants, I'm trying to make it as bullet-proof as possible. How does this sound: Fire/Acoustic insulation in wall/ceiling, 6 mill poly on studs/joists, 1/4" hardi-board on walls (some kind of 1/2" board on ceiling), .... Then I'm not sure. Maybe a layer of RedGuard & then the Kerdi for walls & ceiling & Ditra for the floor?

I guess you ARE trying to make it bulletproof! Problem is that the over kill will actually cause the shower to fail. In addition to the vapor barrier, you're also talking about using two different waterproofing systems, one over the other. One of the three (my choice would be Kerdi), and forget about the other two. Also, you CAN NOT use 1/4" cement board on walls. It must be 1/2".

OK. So No Vapor barrier. 1/2" cement board on walls/ceiling (RedGuard seams/screws?) and then Kerdi on walls & Ditra on floor?
-Owen
p.s. thanks for that quick response! =)

No Redgard AT ALL, if you're going to use the Kerdi.

Thank you for the good advice. I will be tiling above a tub, and will be applying Redguard to the CBU. My only concern is closing the gap between the first row of tile and the tub. If the Redguard creates a membrane that is intended drain moisture, I assume I should not caulk the gap between the tub and first row of tile to allow water out? Or is this okay to caulk the gap because it acts like a masonry cavity wall system where any trapped moisture will be able to breath its way out of the tile and grout?

Can Red Guard be used with radiant floor heating? Tubing inbeded in the concrete.

Bill,
I started a foyer retile job on a house built in 1953. During demo I found the floor has about 1-1.25" mortar bed on top of 1X3s and 1X6s with gaps between some of those boards. The tiles are 1/2" thick and they chipped off but left a rough surface since they had lugs and the wide grout left little ridges. I'm left with an avg of 1/2" of elevation to get flush with the surrounding hardwood floor.
There are a few hairline cracks in the old mortar bed and I'm wondering if I can leave it and add something to minimize the cracking potential. The Tile shop guys said to put Redguard over the cracks and then a thick layer of thinset to raise the tiles flush with the surrounding wood floors. I thought Redguard was more for water proofing than for crack isolation.
I was thinking that I need to level the uneven surface of the mortar bed with either leveling compound or thinset and while I'm doing that, imbed a layer of Ditra (or similar) on it before it dries. Then thinset the new tiles on top to get them flush with the hardwood flooring. Doesn't the Ditra isolate the movement to greatly reduce the chance of cracking? Help!

Hi Bill! Can I use Red Guard sealer on cement floor if I will install electrical heating under tile? Thank you, Nikoai

Bill - need your .02 on my project.

I am building a patio kitchen and need some advice. The structure is constructed out of 3/4 plywood and 2x4s. I had planned on using Redgard around around the base and tar paper the rest of the before putting down the backerboard.

We will be tiling the bar & worksurface with a natural stone for the back and front.

I guess my real concern is the redgard. I would like to protect the base as much as possible.

Ive put tar paper up on the studs and then cement board. Do I need to use redguard over top of the cement board and if I do can I use a premixed motar for tiles. I have caulked the tar paper to the shower surround and I have caulked under the cement board. When I install the tile should I grout or caulk under the tile.

remodeling bathroom,if a tar paper was installed behind hardibacker is redguard needed before marble tile also using a premix high performance thin set(omni grip)I think my tile will bond better & omni grip has a mold type of control am i on the right track.signed mr inexperienced

I'm attempting to tile my tub surround, and I've already got my cement board screwed in, mud and taped. I did not use a vapor barrier, but I purchased the Redguard. I also purchased a big tub of the premixed ceramic tile adhesive. Will the adhesive create a problem for me when I try to put that on top of the Redguard?

I'm attempting to tile my tub surround, and I've already got my cement board screwed in, mud and taped. I did not use a vapor barrier, but I purchased the Redguard. I also purchased a big tub of the premixed ceramic tile adhesive. Will the adhesive create a problem for me when I try to put that on top of the Redguard?

I am planning on using ditra on a floor tile project and I am doing hardibacker and redguard on the shower walls. Rather than buy another product (kerdi band) I was wondering if I could use the redgard to seal the ditra seems or if I have to buy the kerdi band?

Bill.. I really need to know if Redgard will bond to linoleum flooring as I need to put a liner down and then pour a pan for a 10x12 area but can't use a sheet of lining because the liner has to go 2 ft. up a wall that is made out of big rock and morter. My question is can redgard bond to linoleum flooring and the rock wall? I want to put the redgard down and then pour a pan with quicklevel morter because there has to be a drain installed. then level the wall out with mortar and finally install ceramic tile over all of it. Is that going to work?

I need some assistance! All the help I could get actually. My boss used redgard on the gybcrete cement and it's peeling off. Is this normal? He put a primer of water and redgard on the floors first (mopped before applying). Once the primer was dried we put the redgard on and left it for the weekend. Came back to the job site and the redgard was peeling up. We pulled it and it came off in sheets. Is this normal? Please help!!

RedGard can only go over Gypcrete 2000.

Other than that, it sounds like things were done correctly. The primer should have been a 4:1 ratio of water:RedGard, each gallons of primer will cover about 250sqft of gypcrete.

Porous gypcrete may need two coats of primer.

Primer dries in about 45 min to an hour. The topcoat with RedGard.

If the Gypcrete was GC2000 and there was no flaw in your application methods, it'd make sense to call Custom or Maxxon tech support. I recommend taking some photos and having them handy to email the tech guy when you get on the phone with him.

I am redoing shower (contractor 1/2 finished shower and left - vinyl pan with holes in it and asphalt coming thru, holes through sealed walls - i.e. nails to hold up tiles, etc.), two easy flat walls tiled. I have stripped everything. Now I have 1/2" concrete board on walls, clamping drain, preslope mud. I would like to RedGard everything (as in this video which looks like the method works for clamping style tile drain - https://www.youtube.com/v/74GRWfdZsOk?rel=0). Question: I have cutouts in the wall for glass block to be set. How do I seal to or transition to the glass block?

Bill,

We are in the process of redoing our bathroom floor to put down tile. Before we bough tout house we knew there was water damage to the bathroom floor from a long lasting leak from the washer. We have repaired all that damage by replacing the studs in the walls, replacing the sheet rock with the moisture resistant sheet rock, and building up the floor from the joists up and topped with 3/4" Advantech Plywood. We are ready to start replacing the tile but are unsure if we need to put down cement board or redguard, or both. What do you recommend? The subfloors are all replaced with the Advantech, but we aren't sure if we can just redguard and go. Any advice would be helpful. (additional info- we are not replacing the tub/surround, we will be putting our washer/dryer in there again)

Thanks!

Red Guard isn't approved for use over plywood for floors. Ceement board installed over thinset, held in place with the proper screws or nails provides a tileable surface. If you want waterproofing, skip the ceement board and use ditra and band the seams.

Excellent advice.