Mastic instead of thinset for install
housenut1
| Posted in Construction Techniques on
How bad did I screw up? Tile setters just finished half of the tile job in the shower stall with a 3×6 subway tile. I installed the durock with rough side out according to them. It turns out they used mastic and did not fill any joints prior. When I noticed it ~ 2/3 of the way through the job, I ran a bead of silicone caulk in the few horizontal joints I could. The two corners are screwed. My first thought is to pop off all of the tiles, “eat” them and hire someone else to finish the job. They are less than halfway through with the job and have 50% and I will call it even. I should have been clearer in my instructions.
If I have to rip out the job and hire someone else will the mastic remaining screw things up for the thinset?
Replies
Mastic is not the right adhesive to shower tiles as you know and as I now know (even though it says so right on the bucket). Before I knew this, I tiled 2 showers in my own house using mastic. One was done about 20 years ago and the other about 10 years ago. Both showers are holding up just fine. I mean, they're absolutely fine! And each is used 2 -3 times per day.
This does not mean that I'm recommending mastic. I just think it means that if done carefully, grouted well and the grout is sealed, you may not be as screwed as you think.
If mastic gets wet, it will deteriorate. That's why it's important to seal the grout. I don't think I would worry too much about the joints not being taped/filled. Any water that gets behind the tile will probably cause problems with the mastic before it seeps through the joint.
Yeah. You and I might be considered apostates for the devil for saying it, but I too spent years in a house with mastic and greenboard with no problem.
I do know of two showers with mastic on SR that are still fine.Mom's and Dad'sBut they are fanatics about using a towel or squeegee to dry the walls after every shower before they dry their own body.
I hate to say that because it suggests that I have some history of insanity in my family, LOLBut I have not ever seen another shower more than ten years old getting regular use done that way that does not show some signs of deterioration. It is not the standard of quality for this day and age. I have to admit that I installed a lot of tile over greenbd in the seventies and early eighties. Back then it was the acceptable standard, but I know better now.
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"I have to admit that I installed a lot of tile over greenbd in the seventies and early eighties. Back then it was the acceptable standard, but I know better now."
Me too. Right up until the early 90's :(
Last fall I torn out a 20 YO mastic on green board shower that the side wall was actually bulging out.And it had a built in seat. I don't thing that they had any kind of water proofing under the seat. The only thing that held up the seat was 1328 carpenter ants.But even without the seat issue the wall was toast, or should I say soggy toast.Fortunately where was almost not mold or water damage on the studs or subfloor.Now this was compounded by the HO being very unhandy and there had been some attempt in the past to seal the cracks in the wall with caulk.And the HO called me when he saw water dripping in the basement after a shower.And I *think* that the leak was actually at the shower door, but after seeing the rest of the mess I did not really try to determine if that was the cause or not.
.
William the Geezer, the sequel to Billy the Kid - Shoe
I looked at one like that three years ago and told the HO it needed full replacement. He is the kiund who says "I can't afford that right now" and then waits five years until it costs fives times as much to fix all the rot that was caused."Now this was compounded by the HO being very unhandy and there had been some attempt in the past to seal the cracks in the wall with caulk."LOL, so he told me to just caulk it and we'll do it next year.Did I tell you that was three years ago?He called me down last week to talk about designing an addition on the other end of the house.I asked him with a smile on, " Now P, you've been postponing the new roof and that shower repair for three or four years now because you couldn't afford it. Do you suppose this would be a good time?"will be an interesting negotiation.
He can afford about anything he wants to, but has learned the poor-boy line well.
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Thanks Don but I am going to rip it out and take another three years off my life.
Wayne
I would be more concered with the silicone calk you ran on the backerboard!
What are you going to get to stick to that????
Like said, proper grouting and sealing should carry you threw.
But wouldn't do it again.
Hello cameraman:
I decided I am going to rip it out and repace the durock. Thanks for the post.
Mike
While thinset is much better than the mastic, partly because mold won't grow on it, I'd be more concerned about the joints (and corners) not being filled and taped.
Filling the joints basically bonds the substrate together, minimizing any movement. You could have cracks down the road if the joints weren't filled, especially in the corners.
Use the fiberglass mesh tape designed for tiling, and set it into either thinset, or DuraBond setting compound.
If you get the tiles off soon enough, within a day or two of installation, you can probably scrub the mastic off.
Good luck.
Hello Shep:
I learned a costly lesson and will rip everything out tomorrow, I think it will be too hard to scrape the mastic off the rough side. My big concern is how to deal with the pans mudjob / durock intersection. Mudjob goes up the rock ~ inch. Any thoughts?
Mike
Well, the durock shouldn't have been fastened low enough that the mud bed covers any fasteners. So once you've gotten the fasteners out, you should be able to wiggle the CBU out from the mud bed. If its only down an inch, I would think it'll pop out pretty easily.
A couple more answers to some of your other questions- because cement board is vapor porous, a vapor barrier (tar paper or polyurethane sheet) is sometimes installed behind the CBUs to prevent moisture from getting into the wall cavity. Personally, I only install the vapor barrier against an outside wall, where temp differences will cause condensation. My feeling is that if you trap moisture behind the cement board on a warm, interior wall, you may promote mold growth. I really have no data to confirm this one way or the other, but its how I do it.
Also, when you set the new cement board, leave an 1/8" or so gap between the boards. That way, when you mud and tape the joints, it'll get into the joints, and better lock the pieces together.
This might be a PITA right now, but in the long run it'll be worth your efforts.
Hello Shep:
Your idea is what I was hoping I could do. Thanks for the advice and support. I can't wait until I have a beer on the seat in the shower.
Mike
Have 2 beers. You'll be ready for them when your done <G>
Hello Shep:
Finished ripping out the old 1/2 durock on the botched tile job you gave me advice on. For extra strength I decided to put back up 5/8 durock. The only problem is the "pocket" between the pan and finished floor tile (it looks like they installed this adequately) won't allow the rock to slip back in between. Is it okay if I just run the durock to the floor tile?
Mike
Butting the 5/8" should be fine, although I think I'd pack the "pocket" from the old backer with some cement, so so there's not a place for water to accumulate.
FWIW, 1/2" should be plenty strong, especially once the tile is on, and stiffens the wall even more. But there's nothing wrong with a little overkill, either <G>
Hello Shep:
Thanks again for the advice. One of the reasons I was going to use 5/8 durock was so I could use 5/8 GB on dry walls. I guess I can use the 5/8 GB on the other two walls and I'll stay with 1/2 inch for the shower/dry wall.
Mike
those guys are not very good tile setters.
you might as well keep going. just be vigilant about maintaining the shower stall. then as an added safety measure use grout caulk in the corners, pack it in there well.
I've seen tiles installed over sheetrock with mastic that held up well for many years. also have had to rip out the same because of poor maintenance
Hello maverick:
I will rip it out tomorrow and redo. What a stupid mistake on my part to not be better informed. I replied back to all of the posts with one major concern: The mudjob of the shower pan is against the last inch or so of the durock. How do I handle the removal and install so I don't screw it up?
Thanks,
Mike
Tile setters just finished half of the tile job in the shower stall with a 3x6 subway tile. I installed the durock with rough side out according to them. It turns out they used mastic and did not fill any joints prior.
As a couple of others have pointed out, this isn't good...but sometimes you get away with it. If it was only the mastic that was the problem, you might not have to tear it out, although you'd never know when it was gonna die. It could last 5 years or 20. Before I knew any better, I did a laundry room floor with mastic directly on a concrete slab. It's now 15 years old, has been flooded twice and is (thank bog!) still holding fine. But that's good fortune rather than good workmanship. Basically, I screwed the pooch and got lucky. You can't count on that happening every time.
However, the joints have to be taped or you're quite likely to get them telegraphing cracks through the tiles in a year or so. And that bead of silicone caulk needs to be allowed to dry and then peeled completely outta there. So it looks like you've got some scraping, prying, and scrubbing to do.
Get to the tear-out as quick as you can; it'll be easier to remove the tiles without breaking them all--and to clean off the backerboard--if you do it before the mastic dries.
BTW--those hacks don't deserve to be called tile setters; you should back-charge them the full cost of the tearout and any damaged materials that have to be replaced. It is entirely their responsibility to get this sort of thing right. You do not have to specify thinset in a shower stall; that is the standard of the industry, as is taping the joints in the CBU.
Dinosaur
How now, Mighty Sauron, that thou art not brought
low by this? For thine evil pales before that which
foolish men call Justice....
I don't think it was luck with that laundry room- mastic isn't necessarily a bad tile adhesive. I still use it for counter backsplashes and a few floors. Yeah, thinset is better. But I find it a PITA to work with. I usually end up throwing a fair amount of it away because I've mixed too much and it either starts setting up, or I just don't need it. In areas that don't get wet, I still prefer mastic.
And I'm with you on that guy's shower. I'm more concerned about the joints not being taped than the use of mastic. He's going to have some serious problems in the not too distant future if he doesn't stop now and take care of things.
thinset is better. But I find it a PITA to work with
I know what you mean; I felt that way about thinset too until I got a big-arsed Makita drill-motor and a mud mixer. But after I realised how much that laundry room could have cost me if it had gone bad, I got religion. Now I'm so used to using TS, I use it for pretty much everything. I honestly don't remember the last time I use mastic.
'course, 99% of the tile I do is in kitchens and bathrooms, so....
Dinosaur
How now, Mighty Sauron, that thou art not broughtlow by this? For thine evil pales before that whichfoolish men call Justice....
Dinosaur:
Thanks for the advice and I am seriously thinking of doing what you say. What do you think about replacing the durock to save some labor if the cleaning is too much of a bear? Also any tips on a good tool I could use for removal? And lastly, if I replace the durock, how do I manage the mudjob durock intersection. I would appreciate your thoughts.
Mike
What do you think about replacing the durock to save some labor if the cleaning is too much of a bear?
If you've got more time and patience than money, pull the durock, scrape it as smooth as you can, then flip it and re-install it smooth-side out. Modified thinset will stick just fine to either side.
But that's a PITA of a job; most contractors would simply eat the cost of the materials and demo and replace the Durock, because the cost of labour to save the materials would far outweigh the savings. Your call on that; only you can decide how best to allocate your resources.
Also any tips on a good tool I could use for removal?
You'd better not waste any more time thinking about how to peel those tiles off, or you won't be able to do it without an air-hammer. That mastic is drying all the time and once its been in there for a week, your tiles will be almost impossible to get off the CBU without destroying them.
I would start by trying to shove the nose of a steel concrete float or rectangular thinset trowel under the edge of a tile, then lift the heel to lever the tile off a bit. Push it in a bit more, and repeat until the tile comes off. If that doesn't work, try the thin, flat end of a renovator's pry bar, but don't pry too hard because these bars are not as flexible (or wide) as a trowel or float and you'll crack the tile. Use the stiffness of the bar to drive it under the tile and cut through the mastic (tap the bent end with a rubber mallet) rather than to lever the tile up.
As the tiles come off the wall, dump them immediately in a large tub of warm water and let them soak for a day or so. Then pull them out one at a time and scrape the goo off the back.
Honestly, if these are just ordinary 3x6 'tuxedo white' subway tiles, I'd not waste a lot of time trying to save them. It's bound to be a messy, long, boring process, and again, unless you have more time and patience than money, it's probably not worth the trouble unless they pop off quick and easy.
And lastly, if I replace the durock, how do I manage the mudjob durock intersection.
Shep's suggestion is pretty much on the mark, but if that won't work for some reason, cut the Durock a few inches above the mud, spend the time necessary to clean that few inches well, then screw on new Durock above the cut and tape the joint.
Finally, let me reiterate that it was the responsibility of the so-called 'tilesetters' you hired to use the correct products and to tape the joints in the backerboard properly. Mastic is not acceptable in a shower; joints in cement board must be filled and taped; and anyone hiring himself out as a tile-setter today is required to know that. The only way these guys could excuse what they did would be if you signed a contract with them specifying untaped joints and mastic...and I don't imagine you did that.
Dinosaur
How now, Mighty Sauron, that thou art not broughtlow by this? For thine evil pales before that whichfoolish men call Justice....
Hello Dinosaur:
I will eat them because they are the basic 3x6. And again thank you for the time and advice.
Mike
Hello Dinosaur:
I ate the tile and ripped out the durock on the botched tile job you helped me with recently. I used 1/2 inch durock and had a thought to replace it with 5/8. Plumbing will not be a problem but the pocket between the liner and finished tile floor is too tight. Can I just run the durock to the floor tile? This part of the tile work is the only part I salvaged and it looks to be done okay.
Mike
Yes you can, but I wouldn't bother. Half-inch is more than sufficient, both for the Durock and the gyprock.Sorry for the short (and late) answer, but I'm outta town and working on someone else's computer--and it's running Firefox so my text controls don't show up.
Dinosaur
How now, Mighty Sauron, that thou art not broughtlow by this? For thine evil pales before that whichfoolish men call Justice....
Hey Dinosaur:
Thanks again for the tip and I am sorry for the late thank you.
Mike
Not a problem. Hope everything worked out well for you. Post some pix of the finished job if you can.
Dinosaur
How now, Mighty Sauron, that thou art not broughtlow by this? For thine evil pales before that whichfoolish men call Justice....
I think you need to cut your losses now and tear it back out and do it right. They screwed up by not filling joints and corners and by using mastic, though you mention that it may have been your fault because you were not clear with your desires as how you wanted the job done.
I guess these guys are not full time tile setters, because they should have known better.
I have not used mastic in a shower in 20+ years. Chances are better than not that it will not hold up.
Also, if you are going to be installing a shower door over the tile then you have to consider that as well. Just more stuff to tear out if the mastic turns loose.
sully
Hello sully13:
If it's not done twice it's not done right is a motto that is following me a lot these days. After feeling sorry for myself on Friday I am ready to fire the guys. I just hope I can salvage the durock. Someone also feels I can salvage the tiles too but if I have to eat them I will. Any suggestions on how to avoid messing up the durock. I'll remember you if I win the lotto.
Mike
First let me preface by stating that I much prefer thinset over mastic.
Second, I'll toss out that mastics from 10 or 15 or 30 years ago are not the same formulations as the mastics we have today. All that eco- green- stuff resulted in mastic being dumbed down a bit in terms of its durability and/or versatility as an adhesive in certain applications. So when we got away with using it 20 years ago, we really didn't. It might have actually been okay.
Thrice-most, there are two types of mastic; appropriately named "Type I" and "Type II". Type I is water "resistant" and manufacturers recommend it for use in tub surround, shower walls, but not shower floors. Type II has minimal water resistance and is really only okay for decorative tile in dry areas.
So if they used Type I, while it's not as good as thinset, it's not a bad bad unless they used it on the shower floors. then it's uber-bad.
If they used Type II it's uber-bad.
If you have to or prefer to have it all ripped out, then I'd even offer that you could remove, flip, and reinstall the Durock smoth side out. Use a highly modified thinset.
If you feel uncomfortable doing that, you can always just replace the cement board with new material. Durock is fairly inexpensive compared to having to scrap/clean and hope that the thinset bonds well. When you thinset the seams use mesh tape and keep the seams flat.
Did they put anything like plastic sheeting or tar paper between the cement board and the framing?
That was an uber-good post!I like your use of the term 'uber' so I want to add uber to my lexicon. gotta practice it a bit so I don't forget it.have an uber-good day!;)
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Well, I guess we have to go proper and add the umlaut to make uber über.To keep our spelling über-correct and all.
thats a little "uber" the top, dontcha think?View Image bakersfieldremodel.com
Nah, that'd be elitist.I'm just a plain old uberitarian
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Hello Mongo:
Thanks again for your advice it is always helpful, maybe when I hit the lotto I will fly you in to work on my small castle. They did use type I but I am going to rip it out. My only concern is the durock mudjob pan junction. Durock was held ~ 3/4 inch above liner and now is covered ~ inch with mudjob. How do I remove durock safely and how will this affect the pan? When I reinstall why should I have put tar paper or something against the studs prior to the install?
Mike
Hello Mongo:
The botched tile job you recently helped me with was ripped out, except for the mosaic floor tile (looks like this can be salvaged). I had a thought to replace the 1/2 inch durock with 5/8 inch. The only problem I see is that the thicker durock doesn't slip in between the finished tile and pan liner as before. Can the 5/8 just be ran to the finished floor tile?
Mike
Realize that when hanging 5/8" cement board and butting it to the floor, you don't want to drive any fasteners through the pan membrane that runs up the wall. It probably runs 8" or so above the deck mud. So the bottom 8" or so of cement board will be hanging free. Now it's not like it's going to be flapping in a breeze or anything, but if you go that route first do as Shep wrote and pack the slot with mud. Then use caulk instead of grout at the wall/floor intersection. Caulk will flex with any movement, grout will crack.An alternative would be to take a belt sander and make a slight chamfer on the bottom 1" or so of the bottom edge of the cement board. Pack the slot with mud then jam the chamfered edge into the mudded slot, helping to lock the bottom edge of the board in place.Or you could just replace the 1/2" with more 1/2" and jam it in the slot.
Hello Mongo:
Thank you for another great tip. I may just use 1/2 inch after all.
Mike
If still fresh enough, you might be able to salvage the tiles by kitting them with a pressure washer after you slide them off.
P:ut them in something like those plastic shuttle trays the bread delivery guys use, so they are contained for being blown down the driveway by the water blast, but so water can get away.
I would not expect to be able to salvage the Cement board with mastic on rough side tho.
As for how you deal with them - same as any incompetent sub
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Hello Piffin:
I appreciate your advice as always and thanks. I am going to slide them off. When I replace the durock, how should I handle the pan mudjob which is against the durock? This concerns me.
Mike
P.S. Any advice for a tool for the tile removal?
I have to feel my way when I try salvage like this. often a flex putty knife
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Thank you Piffin but I am going to eat the tiles after all. Maybe I'll check if I can recycle them anywhere.
Mike
"check if I can recycle them anywhere."Well, there's always the potholes in my driveway, or the....
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You better watch for the sharp edges of those tiles in your potholes. I know they can do a number on my skin.
They probably wouldn't be too good on your tires, either.
<G>
I know. Actually I use that kind of thing for base material, not the smaller surface holes. I was trying to help humour him thru this difficult period in his project.and wait for another thread to describe how I build my road for free.
( if I can figure out how to word it without sounding too 'frenchy' about it all)
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I was trying to use humor, too. I even went back to make sure I included the little <G> in my post.
I guess Jersey humor doesn't translate well. <G>
I think I'll drop them in the tilesetter's pickup!
Hello Piffin:
I ripped out the old 1/2 durock on the botched tile job. What are your thoughts on putting back 5/8 durock. The only problem I see is that the durock won't slip in between the finished tile work on the floor (the only tile work I salvaged) and the pan liner. Is it okay to run this to finished floor tile or do you have another suggestion.
Mike
Mask the floor tile and mix some generic sanded fgrout for that slot
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Hello Piffin:
Once again I am glad I asked. Thanks for the tip.
Mike
I would try some very hot water in a garden sprayer and run a little along the top row.Then as Piffin says use a putty knife. And use finesse and not brute force. And as you get a tile loose or even just a corner hit it with a little mroe hot water.Don't know if that will work at all or not, but I am basing my suggestion on how I remove wallpaper..
William the Geezer, the sequel to Billy the Kid - Shoe
Thanks Bill for the advice but they are basic subways and I will eat them after all.
Mike
It would probably be mildly toxic but you could probably get most of the mastic off with a heat gun and wide putty knife. Would save your concern over pulling it from the pan. A hair dyer would probably suffice depends on how big of shower it is. If its just your basic shower thats half done, you might be able to get it scraped in a coupld of hours. Now iffin your builing one of them there party showers..it might be just as easy to pull the board and let the rest of us know when the party is. :)
Heat or solvent one of the two should work if you really really don't want to pull the board.
Thanks for the idea but I am going to rip it off and be careful at the pan joint.
Mike