Last year I remodeled my Parent’s kitchen, gutted it, replaced the sublfoor where it was rotted out, hung new drywall, installed the cabinets, and then layed down the flooring. I first layed down 1/2″ Durarock in 3’X6′ sheets, nailing every 12″ with 1 1/2″ roofing nails, making sure to hit the joists where I could. I then used mortar and non-adhesive tape to reinforce the joints. After a day, I started installing the tile, breaking that up into two days (most of this work was done on nights and weekends). I followed up with grout and sealer shortly afterwards. Having worked for a couple of contractors, this is always the way we did it, and I have never had problems with any other floor I’ve installed.
Twice I have had problems with the grout loosening up and tiles lifting and cracking, only in two spots, neither of which is near day 1 vs day 2 seam. I pulled up the problem tiles and laid down new ones, the first time again using mortar, the second using mastick. I made sure no one walked on the floor for a few days the first time, and a whole week the second (I have had problems with mastick drying slowly with large tiles before, is this normal?). Both times the floor looked beautiful for about 1 to 2 months, and then the grout started coming lose followed by the lifting and cracking tiles.
So, has anyone had a problem similar to this? I know the ply subfloor is nailed tight, I renailed all of the old stuff when I installed the new, using #8 ringshank nails. The Durarock base is definitely not moving, I tried lifting it from the edge, and it doesnt budge. I looked at the joists while someone else walked all along the floor, but I couldn’t find and joists that bounced too much. The tile is from a bargain place (I know, but my mother bought it) and I’m thinking that it may be the problem, b/c when I pulled up the tiles, both the mortar and mastick were stuck to the durarock and not the tile. Anyone agree? The worst section is the highest point in traffic connecting the kitchen, living room and hall to the rest of the house. Could this traffic also be part of the problem? Last, should I just rip everything up, and convince them to install wood (either natural or engineered) or laminate?
If anyone has any ideas or thoughts, please let me know. Thanks
Replies
Several questions.
1) Joist spacing and size? 2) How thick and type of material of subfloor? 3) Did you install the Durock into a bed of thinset? or just use thinset to stick the tiles down? 4) Were the tiles in the high traffic areas (where you have already had problems) perhaps installed last on a batch of thinset which perhaps had already started to kick?
Traffic on a tile floor should not be a problem.
Sounds suspiciously like a "floor flexing" problem to me. Note that the Durock can flex independent of the floor causing problems like you describe. Thinset underneath of the Durock will fill any voids between the Durock and the subfloor and minimize independent flex, however, it is not a substitute for adequate framing and subfloor stiffness / thickness.
You will get a number of responses and the quality of the answers will be dependent upon the info you provide.
Jim
Never underestimate the value of a sharp pencil or good light.
1. Joists are 2X10X12', are 16" oc and overlap the center beam by an inch or two.
2. Subfloor was 5/8" plywood (pre-existing, I only replaced 3 sections, and have not had problems in those areas).
3. No I didn't lay a bed of thinset between the sub and durock, although I can see why it's a good idea.
4. The tiles that are the most problematic were installed in the middle of a batch of thinset. I had thought maybe this was the problem, but after chipping and grinding up the old thinset each time I re-installed the tile, I began to think this wasn't it.
I would agree with the floor flexing, though with such a short span, cross bracing between the joist, and I could barely notice movent from below, I am not sure if it's the real problem. Head room is limited below, what options do we have besides installing a beam with lolly columns? Should I remove the cross bracing and install 2X10 bracing between the joists to tie them together better? Do you think a laminate floor would be less of a headache than re-tiling these sections again?
JimCoventry Woodworking
Where do we start. There is a deflection problem in the floor. 5/8” plywood is an inadequate sub-floor to start with. The cement board was dry laid and nailed. You never nail into the joists on the “underlayment” layer of the floor. That is a failure in itself waiting to happen. Mastic should NEVER be used for floor tiling applications. You now have a hobby until you rip it all up and start over. Those tiles will continue to pop over time. The solution? The tile and cement board have to come up. Screw the sub-floor to the floor joists. Add a layer of ½” minimum UL grade fir plywood to the floor. This is your underlayment. Do not screw this layer into the joists. Go to a tile supply house and look for a product called Schluter Dittra. This material is thinseted to the floor with a modified thin set. You then install your tile on top of that with a non-modified thin set. What you have now done is beefed up the structure, and by using the Dittra, you have isolated the tile from the structure. Any shrinking or movement of the plywood will not transfer into the tile causing it to crack or disbond. Your floor joist structure can support ceramic tile. What you have also created is a tile job that should last the life of the house! Oh and this time…go get some good tile and stay out of HD!!!!!!<!----><!----><!---->
I agree that the 5/8" subfloor is not enough, and had origionally planned to lay 1/2" OSB over the subfloor, but was talked out of it by my Dad (fyi, never allow a customer, whether it's family or not, convince you to cheapen a project, I've had a few bad results). He said the origional subfloor was fine, and that he didn't want to raise the kitchen too much from the rest of the house.
Why do you want the floor seperate from the joists? I know mastic shouldn't be used, but after using thinset twice (I wrote mortar, my mistake) and having problems, I decided to try something else. As far as tile goes, it wasn't even from the Orange Box, it was from Building 19 or one other "crap" store. I told her to return it, but she insisted I use it.
Thankyou for your comments, I knew I screwed up as soon as they started lifting the first time. I'm a cabinet maker, not a flooring layer, so I appreciate all the help and info.Jim W.Coventry Woodworking
When the tile contractor comes out to work on my house, I would like to have some idea what is going on. With that in mind - what do you mean by the terms modified thin set and unmodified thin set?
thanks in advance!
Unmodified is basically just a cement mix. Modified has a latex additive that makes it a little more flexible and longer lasting. Most people buy the modified type already blended together in the bag. Mapei Ultraflex is an example. Some people buy unmodified thinset, and also buy a bottle of latex additive, and mix their own.
Generally speaking, you would almost always use latex modified thinset. There are specific uses for the unmodified, so it's not going to go away anytime soon.
"When asked if you can do something, tell'em "Why certainly I can", then get busy and find a way to do it." T. Roosevelt
Modified thin set has latex polymers in it allowing some flex in the bond. When you set tile to plywood (a no-no) a modified thin set is required. An un modified thin set is used when bonding to concrete (another no-no) Both of these setting examples are done everyday. I say no-no because I’m in the biz and I have to stand behind and guarantee my work. I see that the tiles that came up had no thin set on them. One of the most overlooked prep items in the tiling process is “back” inspection. If there is a foreign material on the backs of the tile, the adhesive will not bond to it. Some of the discount tiles that have hit the market are loaded with all sorts of release powders and grits on the back. By foregoing the “cleaning” process in manufacturing, they can shave a few cents off the price. Too bad that I add a whole lot more onto the job if I have to clean all the backs of the tile. Sorry for all your troubles. If you have to, rip it up and do the laminate floor thing. They do have laminates that look like tile. Your sub floor needs a whole lot of work. Laminate is forgiving. The other solution is to let the next owners worry about it. <!----><!----><!---->
> bonding to concrete (another no-no)
I'm going to tile a slab on grade house for my stepdaughter. If bonding to concrete is a no-no, what's the right way to do that?
Thanks in advance, it's clear you really know your stuff. The tip on cleaning the backs probably already saved us big grief.
-- J.S.
Thanks for the info.
What do you use to clean the backs of the tile?
'Nemo me impune lacesset'No one will provoke me with impunity
You can still stiffen the floor by adding to the depth of the joists. Just adding 1 1/2" will make a great difference. I would do it just to prevent the chance of doing it again. use 2 x 4s and glue and screw to the underside of each joist.
1) Joisting sounds OK. I have had luck on more than one occasion by sistering rips of 3/4" sturdifloor rated plywood to joists with some bounce. Glue rip in place and screw 2" oc. 2x10 joists would use a 9" wide rip. Lots of screws, lots of glue - stay completely off the floor for several days while the glue cures. Solid blocking in the area of tile problems might help stiffen the floor between the joists - maybe enough to cure the problem.
2) Me thinks this may be your main problem - subfloor flexing between the joists. I think that 5/8" plywood (or 3/4" OSB) is the bare minimum put forth by some of the tile backer manufacturers. I am old school and look for 1-1/8" subflooring before adding 1/4" backer bedded in thinset, sometimes I have been known to reduce that to 1". I PL the bottom layer, add the additional layer of plywood and screw or 8d ring shank the 2 layers together at 6" oc.
3) No thinset under the backer is certainly not helping - most probably hurting you. FYI, I have always used the 1/4" backers on floors, I view all of the backers strictly as a "tile bonding agent" providing no structural strength.
Laminate flooring instead - I can/will not comment as I have no first hand experience with any of these. However, 5/8" plywood would probably work pretty well under 3/4" hardwood, either prefinished or sand in place.
Luck!
Jim
Never underestimate the value of a sharp pencil or good light.
I suspect that you did not want to hear any of this.
That seems to be the concensous, I really didn't want to pull the whole thing up, but luckily the cabinets went in first, so it shouldn't be too bad. I'm thinking that I will try to convince them to have a lenolium floor installed, b/c I'm moving soon, and would rather not deal with installing new tile. Lay down some 1/2" OSB and let someone else roll the floor down. I hate the look, but at this point I'm looking for the easiest option. Well that, and they are too cheap to spend some real $$ to do it all right or use wood.
As far as whether these were the answers I wanted, not really, but I was expecting them.Jim W.Coventry Woodworking
Well I finally got all of the tile and backer up. I can now see why I need the second layer of ply. The subfloor probably flexes about 1/8 to 3/16 midspane of the joists. A few questions though. Should I run the second layer of plywood parallel or perpendicular to the first? Should I make sure the nails hit the joist, or keep this second layer sperated from the joists? Is 1/2 fir underlayment enough if I will be installing a Pergo type floor (still don't know exactly which brand the intend to buy, but laminate seems to be what they want) or should I use 5/8 or even 3/4?
Thanks again to everyone that chimed in.Jim W.Coventry Woodworking
I am afraid I will have to offer a "couched" reply on the thickness needed for a laminate floor as I have never installed same. 3/4" thick t&g, yes, but no laminate.
I would suggest that you buy the flooring first and follow the manufacturer's recommendations - visiting their web site will usually produce additional info also.
New plywood parallel or perpendicular to existing? I have always laid perdendicular to the old. I have a rigorous schedule of PL glue and screws on 6" centers, hitting the joists with longer screws and staggering new joints from old by at least 12". I try to produce a good laminataion between the old and new. This may well be overkill for laminate flooring. Someone else may know a better answer.
RE: thickness to add for laminate - check out the instructions, then choose minimum thickness based on their recommendations - you may want to go thicker for "finish floor elevation" considerations.
Jim
Never underestimate the value of a sharp pencil or good light.
If I remember what you said ... it's the same tiles both times, and there's no thinset stuck to the back of the tiles when you remove them. Wonder if there's some contamination on the back of the tile. Maybe sprayed with silicone lube or something.
"When asked if you can do something, tell'em "Why certainly I can", then get busy and find a way to do it." T. Roosevelt
This was the origional idea, since most of the tiles came right up with little effort and the backs had little to no thinset stuck to them. I then had to chip and grind the thinset off of the drurock backer, so I don't think it was a thinset problem. When I pulled up a few tiles yesterday, there was some mastick stuck to them, so I wasn't sure if my "bad tile" theory was still correct.
Like I said, they were from Grossmans or Building 19, I don't know, one of those discount stores. I told my mother that I didn't like the idea of using them (none of them were the same size, each was a little different from the other, as much as 1/4", leaving the grout lines looking like crap) and was hoping others might agree. If that's the case, I will still have to pull up the whole floor, otherwise in two years the entire thing will probably be lifting.
This is part of the reason I am moving across the country, I'm tired of doing favors and chores for family and friends, and then having to redo them b/c said person was too cheap to do it right the first time. Oh well, such is life.Jim W.Coventry Woodworking
I'd hardly suggest ripping the whole thing out if only a few areas are having problems.
If the tiles are coming up it's because of something. Diagnose before prescribing.
I'm surprised the expansion question hasn't been asked. Is the tile/grout/thinset being stressed by expanstion/contraction do to uneven heating of the tile? Is part of the tile in direct sun? How far across is the tile floor? A 30' run without an expansion joint is asking for trouble.
Is the moisture level in the framing/subfloor consistant or is part of it more exposed to large levels of moisture?
Keep in mind that tile exsists peacefully with some flex in the floor, but only to a point. The better the thinset is the more flex it can withstand before tile damage. Did you use cheapo thinset or modified, or a really good modified? If cheapo thinsest was used that's probably most of the problem. If a good modified thinset was used then I'd look at the framing.
When it comes to structural floor issues and tile keep in mind that the span ratings that we all like to throw around still allow a significant amount of flex in midspan. L/360 span tables still allow more than 3/8" midpoint flex over a "short" 10' span! With thicker subfloors weight and deflection is spread more evenly across the floor. With thinner subfloors there is more flex between joists, with more probability of poping tiles. Again, how much is too much depends on what your tiles and thinset can stand. Better thinset withstands more flex.
Also, not all joists are created equal and simply stating a size and length leaves a lot to assume. I've seen doug fir joists that were straight grained old growth and much stronger than what we get in a #1 grade today. Others had knots so large and numerous they essentially had no more strength than a board half the size.
We know you have a relatively thin subfloor and spans that allow significant movement. That's a fact. You'll have to reduce this flex to bring the movement into a range that the thinset and tiles can handle without damage. Not all the tiles are being damaged because not all areas of the floor move the same amount under pressure.
Personally, I'd do whatever is necessary to reduce the joist flex in the problem areas since it's not possible to deal with the subfloor directly. If no wires/pipes are passing through, however unlikely, sistering another 2x10 to the existing joist is the most common route. Paying an electrician to pull the wire out of the area to be reinforced isn't real expensive, consisting primarily of installing junction boxes on either side and running new wires through the new joists after being sistered to the old joists.
New blocking, installed tight, between the joists will also help spread the defection across joists more evenly than the old diagnal bracing. More is better.
Best of luck and keep us up to date with what you find.
:-)
Don
Thanks for your suggestions.
The room is 17X13, so I wasn' really worried about expansion (with the cabs, the longest span of tile is 15 ft). Moisture and tempurature shouldn't be a problem, the basement is unfinished, but it is heated. Yes it was cheap thinset, typical stuff you find at HD, not sure of the exact brand. Don't even know if it is modified, the GC I used to work for used it all the time with no problems.
The joists are all pretty good, the only holes drilled through are for electrical, all plumbing is hung under the joists. The section of floor that is the worst is in one corner that connects the kitchen to the living room and the hall that leads to the rest of the house. This area is in the center of the house, partially directly over the center beam, which is a 6X10 with columns every 7ft. I wouldn't think that the joists themselves are flexing in this area since the ends overlap the center beam. I'd be more apt to believe the idea that the subfloor is flexing between the joists (as suggested above).
I'm tempted to rerun the wiring and pull all the cross bracing and sistering and installing blocking, but I'm concerned that after all that effort, I will end up with the same result. I'm leaving for Phoenix in two weeks and need to solve this issue ASAP, otherwise I may never hear the end of it.Jim W.Coventry Woodworking