*
Hey,
Have any of you heard of the new “mortar bed” approach that
came out this year. Basically, it is a woven fiberglass
mesh about 3/4 ” thick (kind of like the fiberglass scouring
pads we use in the kitchen), that is then impregnated with a
proprietary blend of cement / latex / etc that is worked in
by troweling in the special mud. The completed work is
billed as having the same strength as a 2″ mortar bed but
less than 1/2 the weight, and the installation time is
supposed to be quicker too. Benefits include less weight
and much lower finished floor height – two things important
in retrofits where old joists may not be sized properly.
If anyone is interested, I’ll look up the web page and post
it in a follow up. (web site is on my other machine) – sorry, can’t
think of the name ofthe manufacturer right now.
ROber
Replies
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Got to throw in my two cents. In the last seven years we have installed (or sold to others who have installed) maybe 150 tile jobs over wood subfloors. Every one was sheeted with 1/4" X 3' X 5' Hardi-backer. Results: One callback( basement post failed, floor sagged, and field tile cracked)All the rest have held up fine and as far as I know no grout has cracked within the field tile. Use 1 1/2" roofing nails and premium,flexible, modified thinset only. I rest my case.
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I prefer mud beds, however most times this is not practical.The reason i prefer a mud bed is because you have a seperation between the subfloor and mortar bed.This helps to control deflection.Use liquid acrylic in place of water for all mixing.The bed should be 1 1/2 thick with a layer if #4x#4x12ga wire in the middle.Any other method of tile installation will not hold up.I've seen so many people now stapling extruded diamond lathe to the floor,leveling thinset over it and then thinsetting tiles to it. THis method is not an approved method.Any tile setter that has been around long enough shuns the cement and fibre tile backers for floor applications like the plague. By the way I have seen the hardi backer delaminate in wet areas.
*For those who have been using roofing nails to hold the board down, have you used a roof gun to nail? I have always used screws & happen to use mostly dens sheild. I would love the speed of a nailer but am worried about the electro coat nails
*
BACKER BOARDS DO NOT ADD ANY STRUCTURAL STRENGTH TO A FLOOR!
YOUR STRUCTURAL INTEGRITY COMES FROM GOOD FRAMING AND A GOOD SUBFLOOR. ONE PURPOSE OF BACKER BOARDS, AS I UNDERSTAND IT IS TO ISOLATE TWO DISSIMILAR MATERIALS FROM EACH OTHER. WOOD EXPANDS AND COTRACTS AT A DIFFERENT RATE THAN TILE AND SIMILAR PRODUCTS.
PATRICK L. MCCANN
*Do you use the thinset under the Hardibacker along with the roofing nails, or just the nails?
*
Dear Patrick McCann,
You would't by any chance be a wood flooring expert also, would you?
Joe
*S.O.P. is that you do.
*Rob,Have you tried an auto feed screw gun? I wouldnt trade mine for anything.Rick Tuk
*i have used wonder board once on a floor. no thinset, used an air roof nailer, worked fine but it was over a very strong sub floor. it was on the original 1" t&g sub floor then i added 1/2" t&g ply-wood. also tiled over an existing tile floor set on a morter bed. no matter what, one thing was common a strng sub-floor.
*Joe, I read this last night and thought the same thing LOL. Chuck
*
I found the material referred to in my previous post.
http://www.laticrete.com . They have a product called Quick
Screed. It is a structual support system for ceramic tile
that is only 1/2" thick, yet provides the same support as a
2" mortar bed.
Anybody used this material yet?
*
You guys are so full of it. Backerboard has good compressive strength, little tensile strength. It will not, and is not intended to, beef up a floor system. It is, quite simply, as Patrick mentioned. That is a tile backerboards intended use.
James DuHamel, backerboard came about because of innovation; the same way thinset, sanded, and colored grouts came about. What this means is that someone saw an opportunity and made a niche. Joe Wonderboard saw this, as did James Hardie. The explosion in DIY came way later. The products may be used by laymen, but they were not marketed for that purpose. In fact, the sheet products were intended for use by professional tradesmen. Hey, just like another product: plywood.
Reinhard, get out your current copy of the TCA Handbook. You'll see that thinset o/ lath IS an approved installation method. Sad, but true. I would never use this method for anything in the world, so I don't pay any attention to what they say. Consequently, I cannot direct you to the Specification # regarding this method. None other than Joe Tarver--3 years ago--told me this is now an approved method.
I have had minimum experience with the product to which RobbWilson refers. A homeowner insisted--that's right; made it's use mandatory--this product be used for all his floors. I hated the s###. I'll never use it again. In fact, I think I'll go bomb the plant where it is made. So many problems with that stuff that I'd be here all aftn writing them down. Basically, took the same amount of labor as a mud substrate, but the results were terrible. The homeowner, bless him for his ignorance, loved it.
Last thing: Reinhard: regarding your stated mudbed thickness, you may want to consider asking an arch. what the specs are for a mudbed.
Such passion in my words I cannot help. Sorry to Fusco you like this.
*
Rich can you set tile directly on 1 1/8" T&G subfloor with thin set or does it have to be isolated from the subfloor in some way.
*
Came back here to check what blistering I would've recieved by now. Lo and behold, an honest question.
S Crawford: No, you would not want to set tile directly on the T & G. Before I get into the "Why nots", I say there is one exception. IF you want to use some sort of highly flexible epoxy for the adhesive AND the grout, you may get away with it. Yet, even using such "exotic" materials, you'd still have some seperation in the adhesive and the grout joints. Basically, you'd only be minimizing the seperation by using epoxy.
I would install an underlayment over the T & G that permits an adequate tile bond. Wood, especially plank T & G, would expand and contract at such a rate as to crack the grout joints first, then crack the tiles, then altogether pop the tiles. Then there is the warpage associated with wood movement. This would result in the same tile defects as above. Then, dependant upon the species of wood, the tile bond would not last. (That is, with some wood, the tile floor would last longer before you noticed defects. Nonetheless, eventually, you would notice a failed tile floor) Heck, the whole tile floor could actually remain intact--no grout or tile cracks--but the entire floor would seperate from the wood. The whole floor would sound hollow and look like it has buckled, which, of course, it would have done.
The tile underlayment could be a sheet good--Hardibacker, Denshield, Wonderboard, etc.-- or a mud bed, or sheet vinyl fastened securely over the wood. However, the sheet vinyl would very probably be inadequate because it is a T & G subfloor. Too much wood movement for just a layer of vinyl to handle.
What I would suggest is either a single layer of 3/8" ply glued and screwed to the T & G with a tile backer board over that, OR, a full thickness wire reinforced mud mortar setting bed. In the former, the plywood is used to provide a flatter and more directional stable subfloor surface for the underlayment.
*
Rich I use SYP 1 1/8 x 4 x 8 T&G flooring over 11 7/8 wood I-joists 16" o.c. I have used dens-shield on hot tub deck surrounds and really liked it. Didn't know if it was compression resistant enough to use on the floor. P.S. I'm not in the floor covering business. ( You've probably already figured this out.) Just a builder trying to do top quality work. Always continuing to learn.
*
Rich, if this is you on the warpath it might get you in trouble at a tea party but surely not here. I value listening to and learning from your experience.
Slavishly using backerboard, ad
P.S. I liked Hardibacker on a countertop I just did because it doesn't crumble in small pieces -- but not on the backsplash -- the screws were annoying and a pain to drive compared to the hi-lo cement board screws through wonderboard/durock. Sound about right? I'll try thickset sometime soon, I still like playing in the mud...
*I have used dens sheild in my house for 300+ ft on the floor. It's 3 years old & performing fine.
*I remembered, belatedly, that we've been over this ground a bit before -- visit: Rich "I WILL NEVER FLOAT AGAIN..." 4/6/99 10:08pm
*Whoa, daddy! Here he is again. S'up, Andrew? Say...you're not one of those virtual stalkers...are you? Gotta' tell ya', it's giving me the creeps. I can back up everything I've said here, but...well, I've just never been in the crosshairs before.
*
You can trust Rich on this stuff. He's been there and done that.
*
Hey Rich,
You are right. Backer board came about because of innovation, and creativity. Only problem they had was that there was no market at the time. They went out and tried to get tile setters to use this "new product". Low and behold, the tile setters told them to go take a flying leap. The tradesmen are slow to try new methods, new products, and new techniques. I think they should be. The old tried and true methods work wonderfully, and until someone else works out the bugs and problems of those new products, I use the old methods and old products. I cannot afford to take chances on new products in a clients home. Once a product has been through all the field testing, and I get positive responses from tradesmen using them, I will try them out.
I went to a trade show in Houston this summer, and I spent some time with the reps from USG. They make cement backer board (can't remember if it was Durarock or Wonderboard - Wonder Board, Durarock, and James Hardie products all had booths there)). They have the history of their products in a written form, and a nice story it is. It tells all about how backer board was first marketed, and rejected. Then it tells of their marketing strategy for the homeowner/DIY'er. The reps claim that the boards sold in the home centers are only 3' x 5' so they can be easily handled and transported by average homeowners. They do make larger sizes for the commercial tile business.
The explosion in DIY projects came about in the mid seventies. Home Depot started in the late seventies, and Lowes was sometime around that same time frame. These stores saw the need then, and grew at a startling rate every since.
I have learned that different areas of the country have different techniques, styles, and preferences. What works well on the east coast won't work in the deep south regions, and what works on the west coast won't work in the far north. Product choices are the same way. Tastes, styles, and techniques are as different as night and day.
Anyway... food for thought, and maybe some discussions.
James DuHamel
*This weekend I walked through the grand openning of a Menard's (we were driving by) and I found a tall stack of Durock. An awful lot of it looked like cheap plywood stored in the rain: wavy. Durock warps? Apparently.Rich, rant all you want. I also appreciate your contributions to this board, thank-you.Rich Beckman
*Coincidence. Virtually. :)
*Ya' know, Beckman, you're onto something when you mention finding inferior or damaged goods at the Big Box. These guys aren't wholesalers, they're retailers, albeit on a huge scale. Their markup is just like the more traditional retailers. But, this is not what I find so facinating about this industry segment.That they can buy whole trainloads of one product--and of course they carry thousands of products--they can afford to take a loss on lots of items--the grandaddies of loss leaders--on such a scale that would put small towns out of business. That they leave whole pallets in the weather or take the 2nds of a mfg's product doesn't even faze them. Besides, the people gobble them up, the ignorant sluts.
*"ignorant sluts"? You been snorting the mortar again?
*Epoxy grout is subject to the same movement as portland grout, and does not have much more deflection. Epoxy grout is more chemical resistant and less porous, that is why it is spec'd for jobs.It really has little to do with strength.Like an expansion joint in concrete,the grout joint will usually seperate before the tile.
*I agree with Reinhard in regards to epoxy grout. It is not a question of increased shear or tensile strength, but one of increased ductility. As I see it, this applies to the question at hand in that the use of the epoxy--for tile bond and grout--will offer increased performance of the floor finishes. This will be evident that there will be less large cracks visible than when using a portland-based product. BUT... they WILL come if the subfloor system is inadequate.In no way will the use of epoxy in the aforementioned manner add strength to the floor system, only it's resistance to an applied force. So, back to the top: it's only as good as what's underneath it.
*
Have just been pitched a line that cementboard on top of plywood subflooring increases the stiffness of said floor, substantially. This is news to me as, the way I see it, that product does not have particularly great strength in bending properties. I mean, if I was to suspend a five-foot long (standard size, I think) half-inch thick piece of that stuff between two joists that are 16-inches apart, I'm not so sure that I'd consider standing dead center on the bridge. Is this just a marketing ploy to sell more product? Anyone have any thoughts on this?
Brian
*Brian-Some people use wonderboard on top of subfloor to lay tile. IMHO, wet bed is much better, and I'm not brave enough to try wonderboard in a clients house.It will stiffen the floor to some extent, not because of the bending strength of the wonderboard but because when the floor deflects, it will try to make the wonderboard slip in relation to the plywood (shearing), which acts against the screws holding the wonderboard to the plywood and not against the wonderboard itself.I'm no engineer, others here are, and I'm sure someone else can do a better job of explaining, but in short it will stiffen the floor, although "substantially" might be stretching it a bit.
*I'm not an engineer,For instance I actually get some things done. When 1/2 cement board is set in a thinset bed and nailed or screwed to the subfloor it probably becomes another lamination. One more lamination will probably not correct an `unsound' floor.Joe
*Nick...Joe,Thank-you both for your reasoned responses. Your insights are about where mine are at, at this point, anyway....it's hard to reason that the Wonderboard doesn't add at least something, to the strenth of a subfloor. But it is, IMHO, brittle, and that property does not bode well for strength in bending. I understand that it offers superior bonding performance, but, then again, I've never heard that plywood fails in that area. Unquestionably, I'd use it for shower walls and bathroom ceilings, but I don't think I'd shell out the $11+ per 30 X 60-inch sheet for sandwiching it between an already stiff plywood subfloor and 12-inch square tiles in a kitchen. Furthermore, if the subfloor wasn't stiff enough, my money gets spent upon an extra layer of half-inch plywood and proper nailing techniques.Brian
*B,You werent listening. Cement backerboards come in second to a mortar bed. Not to a layer of 1/2 inch plywood. Also manufacturer requires a 3/4 sublooor under it. As mentioned above it has to be thinset to the subfloor. We have been using it for over 10 years without a problem. My tile man prefers 1/4 inch hardiebacker to the others out now. This method does not save much money over a wet installation. we usually use in retrofits. It means less mess in someones house. and can be done thinner than a mortar bed.-Rick Tuk
*B, You are putting a piece of Duroc on horses and comparing that to Duroc that has been laminated with thinset to a floor. Not quite the same.For instance ANSI recommends plywood for a setting bed to be a minimum of 1-1/8" thick but recommends 2 layers of 1/2" staggered and glued to be much stronger with less flex.If you are going to use plywood at least make sure it's exterior glue,and if it is a wet location go with the cement board or mortar bed.
*Why the preference for thick beds, aside from perfect leveling? I know this has been discussed before ... but still have the impression thick bed is for old-timers. Maybe that's just Durock advertising!I'm using Hardibacker for a countertop and like that it doesn't crumble in narrow strips or fastening close to the edge. I liked being able to countersink regular hi-lo screws into the Durock, however (I'm using wafer-head screws with the Hardibacker that annoying the trowel skips over, is that what Barry's tile guy does, or roofing nails?). Will be doing a bathroom floor for myself soon and have no problem with laying a mortar bed.The thick bed -- what type of mortar? Over expanded wire lath?
*The thickness is to prevent flex which can cause tiles or grout to crack. I use screws for backer bd on walls, but on floors & countertops where I bed it with thinset I use roofing nails 8" oc. Once the thinset dries it isn't moving. When we do a mortar, the tilesetter uses a curing membrane & wire mesh. I think the mortar is mixed something like 5 parts sand,1-1/2 parts cement, & 1/2 part lime. There might be a bag mix, but that's what they use. You might check the FH bookstore, they have a book called "Setting Ceramic Tile" by Michael Byrne. He sometimes contributes to FH and has some useful info.
*Already have it! But he, like the wise men here, tends to say wistfully "there's nothing like a thick mortar job" then go on to talk about backerboard. Nice section on shower pan though.
*Hey,Have any of you heard of the new "mortar bed" approach that came out this year. Basically, it is a woven fiberglass mesh about 3/4 " thick (kind of like the fiberglass scouring pads we use in the kitchen), that is then impregnated with a proprietary blend of cement / latex / etc that is worked in by troweling in the special mud. The completed work is billed as having the same strength as a 2" mortar bed but less than 1/2 the weight, and the installation time is supposed to be quicker too. Benefits include less weight and much lower finished floor height - two things important in retrofits where old joists may not be sized properly.If anyone is interested, I'll look up the web page and post it in a follow up. (web site is on my other machine) - sorry, can't think of the name ofthe manufacturer right now.ROber
*Andrew, I can tell you one reason a mortar bed is better. It has strength itself and doesnt rely on plywood for it. I have repaired many subfloors and even joists that have rotted out in bathrooms. In most cases I can save the tile floor! If the subfloor fails under backerboard I doubt this would be possible. Even so I am using hardibacker in my own home. It is a small bath and I didnt want to pull the old subfloor and drop it down. The backer board does make for less labor that way.-Rick Tuk
*Hello All,I think people are missing the whole concept of why the backerboards came about in the first place. The Home Repair and Improvement industry (new construction not included) is now well over a $175 billion a year industry. That's alot of moolah! The do it yourselfers are starting to make up a very large chunk of that amount. The material manufacturers have started to make things plain, simple, and affordable for homeowners to tackle as many of these jobs themselves as they can. Look closely on lots of material labels, booklets, etc... and you will see detailed, step by step instructions for use and application methods. Heck, they have videos, weekly how to shows, and workshops in stores now. Cement backer boards came about because homeowners loved the look of tile, and wanted it in their homes. The old tried and true mortar bed application was far beyond their skills or knowledge. In order for the manufacturers to be able to sell their products to the average homeowner, and make installation by them feasible, they came up with cement backer boards. This low cost alternative gave them an opportunity to install tile themselves. (Then most of them call people like us to come to their house and re-do all of the tile work CORRECTLY). Over the last few years, the use of cement backer boards has become commonplace, and even pros like us use them. They provide a quick, easy alternative to mortar beds, and they can be used just about anywhere horizontally or vertically. They have basically made it faster for ALL of us to install tile, and a myriad of other products in areas that used to be troublesome, or very time consuming to work with. In other words, they have made life a little easier for all of us. There are still areas that require a mortar bed (such as shower pans), but it won't be long until they have a product out for those areas also. Anyway, just a thought.James DuHamel
*For floors, I no longer use Mortar beds. We pull off the subfloor, nail on 1 and 1/8" tounge and groove ply, and use Hardibacker for the substrate. Same thickness as a subfloor and a finish floor, and twice as strong.That 1 and 1/8" subfloor is simply awesome. I can't believe how strong and solid it is.