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SWB04 01-08-2015 11:27 AM

Contractor walked off the job
 
Hi folks,

I've read the forums quite a bit in the past. I'm a "DYIer" and have installed tile, travertine, and pavers before. For the current job, a master bath remodel, I hired a local licensed contractor to install approximately 230 sq feet of 18"x18" travertine, including a separate shower, bath surround, and 80 sq ft of flooring.

I work at home, so I've observed and monitored progress. I'm probably more of an "active" client than this guy has experience with, because, frankly, I have some skills and know a bit about the area of work. The only way to ensure a job is done right, in my experience, is to monitor the project.

Thus far, he performed demo (of original builders white tile, including haul away), hired a 3rd party contractor for the shower tub hot mop job, installed the shower and tub faucets, and installed 1/2" Hardibacker "wet area" cement board throughout the rest of the bathroom.

I was away when he installed the CBU. As part of the remodel, last evening I removed one of two "dutch" closet doors, and replaced the other with a sliding door (modifications that the contractor was aware of). I had to peel up a strip of the backer board when framing the wall, and discovered that it had been applied with glue. Additionally, when I had asked the contractor about sealing the floor cracks earlier that day, he reluctantly agreed and applied a fiberglass tape with Redgard. (He sealed all CBU joints with Redgard).

Between the two issues, I was concerned about the sub-floor preparations as I was aware that Hardy requires a thinset base, and thinset on the surface between the joints. I confirmed this with a phone call to Hardy this morning, and then asked the contractor about the installation.

He responded that:

* He'd never been so micromanaged in his life.
* He felt personally insulted. He would not discuss the issue further.
* He'd been installing this way for 13 years and never had a call-back on one of his jobs.
* He picked up his equipment and walked out. He left a new "Harbor Freight" saw behind that he was testing (called it "garbage") and may or may not return for it.
* He offered to refund a third of the cash received thus far; don't know if that'll happen, and I doubt it'll cover the difference remaining for the demo, rework, and travertine installation.

I tried to discuss this with him, but he refused. I asked "this is business, the issue is how do we make this right, I'm not trying to 'injure' you financially or professionally, I just need to ensure the installation is done to industry standards." I never raised my voice or got angry; I played it "straight" as an arrow, and was friendly with the guy throughout.

I have already paid two-thirds of the total contracted price, so in addition to having tons of travertine in my front yard, an unusable bathroom, work that needs to be redone, I'm probably out part of the cost of the installation.

Any advice from the pro's here on how I should proceed? As far as I can tell, all the work has been done well, except for the floor. The hot mop, plumbing (replacing the tub and shower plumbing), and CBU on the shower and tub appear to have been done well, except that the joints in the latter areas should probably have been sealed with mortar before Redgard.

I really don't want to hurt the guy - he seems like he does quality work. I want to be fair, but I'm on the hook here.

Thanks for reading, and in advance, for the advice. I can send pictures if it will help.

Regards,

Scott

cx 01-08-2015 11:47 AM

Welcome, Scott. :)

If you'll add a geographic location to your User Profile it'll appear permanently so folks will know in what part of California this is taking place and perhaps to help answer some of your other questions.

"Micromanaging" is something all construction contractors are a little sensitive to, some more than others, obviously.

Pointing out that product manufacturer's installation instructions are not being followed is not micromanaging.

Hardibacker, among the available CBUs, is particularly sensitive to errors in installation, especially on floors. Installing it without the required mortar bed under it is a recipe for failure. Failure to properly treat the joints between panels is the second worst thing you can do in that application.

Not at all sure why they'd install CBU on all the walls of a bathroom, but that's another discussion. And treating the joints there with RedGard is not per manufacturer's instructions, either.

Did anyone ever evaluate your floor structure to determine if it qualified for a natural stone installation?

What do you do now? I dunno. Best choice would be to complete the project yourself, but if that's not to your taste, you gotta find another contractor. And getting someone to fill in behind another contractor who has abandoned the job is never an easy thing.

Photos are always welcome and might help. Use the paper-clip icon above the Reply dialog box to attach photos from storage on your computer.

My opinion; worth price charged.

Premier Designs 01-08-2015 01:18 PM

Quote:

He responded that:

* He'd never been so micromanaged in his life.
* He felt personally insulted. He would not discuss the issue further.
* He'd been installing this way for 13 years and never had a call-back on one of his jobs.


Translated to ... he had been caught doing unscrupulous work.




Only thing I can add is it pays to research contractors before hiring one, I have never asked for money up front, I get paid when I'm done with the project ...

SWB04 01-08-2015 01:28 PM

7 Attachment(s)
Follow up:

Contractor returned to get his saw and returned some of cash, so we parted with a handshake. I've essentially paid for 50% of the job, with not a tile laid. I'm losing some, but not as much as I could have if he'd finished a sub-standard job.

re: "Did anyone ever evaluate your floor structure to determine if it qualified for a natural stone installation?"

No. The original installation was white 4"x4" builder's tile there floated on a 1" thick bed of mortar. Also, the (second story) floor construction is one foot high composite I-beam's, 12" on center, covered by tough and groove composite sheet subfloor, i.e. a 1992 era house built by a developer with a good reputation, so I was pretty certain that the bath floor was stable enough handle stone.

Photo's attached.

I'm looking at other options now. I realize that it'll be tough to get another contractor to pick up the work, without demo'ing everything and starting from scratch. I was tempted to do this job originally, but my back isn't all that good, and I've been jammed between work and other renovations.

I still may pick up the work anyway. If so, I'll probably demo the floor and reinstall the backerboard properly on thinset, do the same for the joints, strip off the tape and redgard from other joints (wall/tub) and seal those with thinset, and then cover all the CBU on all surfaces with redgard.

Thanks for the advice.

Scott

SWB04 01-08-2015 02:00 PM

Well, my son-in-law's Dad is a professional contractor in Florida, he reviewed the preparation, and said that gluing CBU to a wooden subfloor is how he'd do the installation, too, as would everyone he works with. :rolleyes: :bang:

The subfloor feels plenty solid. I asked the Hardy customer service guy "why" they recommend a thinset base versus glue, and he said "it fills any possible voids". If my floor is solid and has few if any voids, then the glued on CBU should be as solid, particularly after adding mortar and travertine on top, as the CBU over thinset base installation.

I'm wondering if I'm nuts or if I'm the only guy out there that reads directions and attempts to build to "best industry practices".

Scott

cx 01-08-2015 02:33 PM

Scott, if you'll visit our FAQ you find a brief tutorial on how to post and attribute quotes here on the site. Very simple once you see it. :)
Quote:

Originally Posted by Scott
tough and groove composite sheet subfloor

I'd wanna know more about that "composite sheet."

If the original plans did not call for a natural stone installation it's rare that the floor structure would meet the L/720 deflection requirement for a natural stone installation. That's twice as rigid as the requirement for ceramic tile.

Natural stone also requires a double layer of subflooring, regardless the joists spacing. You also don't meet that requirement.

Quote:

Originally Posted by Scott
my son-in-law's Dad is a professional contractor in Florida, he reviewed the preparation, and said that gluing CBU to a wooden subfloor is how he'd do the installation, too

While he may accept money for his services, if he refuses to follow product manufacturer's installation instructions he's not being very professional at all.

We constantly recommend work according to building code, product manufacturer's instructions, and best building practices here, Scott, but our visitors report many, many contractors who care little about any of those requirements. And in your part of the country it seems they care even less than most, I'm sorry to say.

I know that James Hardie has done testing of his product specifically to determine if incorrect installation, including lack of mortar under the panels on floor installations and lack of taping and filling the joints and concluded that your risk of tile installation failure is enormously higher with those defective installations.

And I can't imagine what they hoped to accomplish by painting RedGard over the joints in the floor panels and the fastener heads. :scratch:

All that and you'll be installing Travertine, one of the weakest of the available natural stone tile selections.

Entirely up to you, though. :)

My opinion; worth price charged.

SWB04 01-08-2015 03:04 PM

Quote:

Originally Posted by CX
I'd wanna know more about that "composite sheet."

If the original plans did not call for a natural stone installation it's rare that the floor structure would meet the L/720 deflection requirement for a natural stone installation. That's twice as rigid as the requirement for ceramic tile.

Natural stone also requires a double layer of subflooring, regardless the joists spacing. You also don't meet that requirement.

"Composite" is a lazy guy's way of saying, "I didn't cut up the floor and look at it", but code for this area in 1992 would have specified tongue and groove OSB (it's not plywood), probably 1/2". You are correct. I need to know this, so I guess after I pull up the hardibacker, I need to also pull up a floor board, verify the joist type, spacing, and dimensions, and the flooring as well.

I already have 1/2" CBU over OSB. I considered possibly installing 1/4" CBU properly (with thinset) over the 1/2" CBU + OSB subfloor, but that wouldn't solve a deflection problem. Plus, 3/4 hardibacker + thinset + versabond + travertine = a mountain-sized step up from the carpet. However, with a double subfloor, there'll be a sizable ramp at the transition anyway.

LOL.. I guess that I'm going to do this myself, since I can't (or don't) trust a contractor to do this. I interviewed several contractors prior to selecting the last guy. Measuring deflection should have proceeded the statement of work and bid; none reviewed or discussed deflection.

I want this resolved fast and the bathroom done quick, which is a good reason to SLOW WAY THE HECK DOWN, and get this done correctly.

Thanks again,

Scott

Premier Designs 01-08-2015 03:43 PM

As stated above, it's always best to do the job right. So many people/contractors have issues with that concept, just because others shortcut their work doesn't mean its Ok to do so ..

Do not add a layer of 1/4" of any product, anything that thin is useless for your application ..

SWB04 01-08-2015 04:48 PM

Subfloor calculation dementia
 
I've been researching the requirements to properly achive L/720+ deflection over a wood subfloor, and the results are beginning to freak me out. I've seen instructions calling for multiple layers of 3/4" plywood over multiple layers of unmodified thinset/mortar, plus the CBU and/or membrame, etc.

How does one upgrade a bathroom floor to L/720, plus mortar and 1/2" travertine, without having a 3" step up from the adjacent carpet floor? Second, there doesn't seem to be anyway to accurately calculate deflection unless I pull the subfloor (and new CBU) up. My review of the construction was while working on plumbing and other projects from below (i.e. kitchen is below, bedroom & master bath above). I'm beginning to think I'm going to have to install the base subfloor between the trusses, supported by cleats, and then start with the mortar, second sheet of 3/4" plywood, mortar, then CBU, then mortar, and travertine.

So in summary, that's 3/4" Ply #1, 1/4" Thinset, 3/4" Ply#2, 1/4" Thinset, 1/2" (CBU), 1/2 (Or 3/4"?) Versabond, 1/2" Travertine. = 3 3/4", or 3" if the #1 ply subsurface rests between the trusses. Heck, I'd need a 4" step-up/curb between the master bedroom and bath. Do people actually do this? :uhh: Why not simply poor a 4" slab over reinforced tresses in the target install area?

There's almost "too much" information on sub-floor preparation. I could spend a month just trying to verify all of this. No wonder some contractors take "short cuts". If the "simpler method" works for 95% of installations, or even 90%, the extra cost and labor required to prepare a subfloor or natural stone over a wood subfloor correctly becomes difficult to justify.

Thanks.

Houston Remodeler 01-08-2015 04:59 PM

Scott,

I don't know where you're getting a 3 layer recommendation :eek: Stop reading that site.

To get the proper deflection has nothing to do with plywood. That's all on the joists.

We've made it pretty darn easy with our handy dandy deflecto-lator linked in the dark blue bar above. Once you enter your information, you will get your current deflection. If you need to beef up your joists, you can keep adding joists (sistering) or adding joists (spacing less than 16"OC) until the proper deflection is reached.

Let us know what you find.

Natural stone requires 2 layers of plywood which is usuall 3/4" covered by 1/2" installed in a very specific manner. But we'll get to that later.

cx 01-08-2015 05:30 PM

Quote:

Originally Posted by Dan, post 8
Do not add a layer of 1/4" of any product, anything that thin is useless for your application ..

He was talking about his tiling substrate, Dan, and the 1/4" is perfectly acceptable for that and is the recommended thickness from all CBU manufacturers who make a 1/4" board.

SWB04 01-08-2015 07:34 PM

Deflection
 
I've got deflection estimated at L / 1916, based on:

* 12" SCL "I"-joist (assumed)
* 3" wide (assumed; 3-6" W)
* 14' long between two load bearing walls
* 12" on center (assumed)

I have a section of the floor that I'm framing (closet; replacing two doors with one pocket door), which I will open up a strip of subfloor there tonight to verify those assumptions. I've been into that ceiling/joist area 2 or 3 times, and those dimensions are as I recall it, i.e. very tall I-beams, 12" on center. Opening up the floor will also verify the OSB subfloor dimensions.

More soon.

Thanks!

Splinter 01-08-2015 08:04 PM

Nope... you cant run your I-joist numbers through the Deflecto.. It doesnt work that way..

Who told you to bed multiple layers of plywood in thinset? :wtf:

Kman 01-08-2015 10:47 PM

It's unusual that your joists were placed 12" on center, I don't see that very often...or ever. However that's a good thing for you, and if you have some access to them you might be able to find a manufacturer's stamp that will lead us to the right answer.

14' span is not especially long for an engineered truss, so it's very possible that they're adequate for your travertine installation.

Platypus 01-09-2015 10:02 AM

Nothing irks me more than seeing waterproofing membrane applied ONLY to the seams. Betting the jokers that do this are charging for the whole gallon... over and over.

If it's not a continuous, integral sheet, just don't even bother.

HomeDepotAssociate 01-09-2015 04:55 PM

Quote:

And I can't imagine what they hoped to accomplish by painting RedGard over the joints in the floor panels and the fastener heads.
Lurking in here, ordinarily when you are painting redguard are you skipping over the joints or would that be done before painting redguard? (the tape and mortar over the joints). Not to derail this discussion, my condolences to the abandoned project :(

cx 01-09-2015 05:05 PM

Chate' if you'll visit the FAQ you'll find a brief tutorial on how to properly attribute quotes you post here on the site. Very simple once you see it and people won't hafta go searching about to determine what or whom you might be quoting, eh? :)

Nothing ordinary about this particular use of RedGard. No idea what might have been the contractor's intent.

HomeDepotAssociate 01-09-2015 05:29 PM

OOPS! lol. I got half the attribution. Sorry, that irks me too (quotes without the names of the person who said it). Or maybe it doesn't irk you. . In any case, wouldn't you redguard over the joints after you've done the taping/thinsetting? (some of the comments here made me realize I didn't quite understand the handling joints with redguard during an installation)

SWB04 01-10-2015 11:57 PM

Update
 
7 Attachment(s)
Well, folks, this has been quite a bit of fun. I hired a contractor because between my business and other ongoing home pre-sale renovations, I just don't have the time to deal with it. So then he left, and **whoosh**, I guess I now have the time. :uhh:

I've spent several days reading and planning, so here's a status update, my plan of action, and a bunch of questions. Appreciate the advice, in advance.

Contractor:

My son (Construction Management major) did the research and almost pled with me to go after this guy's license, and seek reimbursement. The Contractor offered me $1000 back, I took it, I figure I'm about $700 out on the deal, but no lawyers and no delays to getting this moving, so I'm good. He's out; that episode is done.

So, I'm my own Contractor (again - how many times has his happened to me; I check references, I interview, but I always seem to have to step in to ensure the job is done correctly). I'm hiring a couple of recommended tile setters to help out, but am doing the subfloor preparation myself.

Where to go from here?:
(a.k.a. help! questions!)

Subfloor:


The joists where originally (1991) made by "True Joist Corporation", now absorbed into Weyerhaeuser. They are marketed as the "Trus Joist Silent Floor" system. Specs are here:

www.woodbywy.com/document/tj-4000/

Joists are TJI-110 Joists, 11 7/8"H x 1 3/4". They are NOT spaced 12" on center, as I previously posted. That situation is in the garage, which includes a 20'+ span with a second story house above it. The bathroom subfloor is supported by joists 19.5" on center, which is in spec for a 16' span (we're at 14' I believe, so it's actually overspec).

My (Construction Management college major) son took on the task of calculating deflection from LP's documentation, and he arrived at 0.143. The "Deflecto" calculation was 0.210 for a load deflection of L/798 based on Doug Fir. So, based on the superior strength of the composite I-beams, we should be covered in any case.

The subfloor panels are unfortunately, garbage LP waferboard, which was standard in 1991 (I guess OSB is standard today). So here's the subfloor plan:
  • There's no way I can save the glue'd in existing CBU floor layer. So, remove and destroy the 1/2" hardibacker. With the Redgard filled screws and construction adhesive, this could be fun.
  • Add plywood reinforcing to the waferboard subfloor. I've literally read this web site and others for hours, and I haven't seen any uniform subfloor standard for stone. (It seems to be slightly different for every installation.)

    --> Are two sheets of plywood required, or one?
    --> 1/2" plywood followed by 3/4" sheet?
    --> One sheet of plywood of 5/8"?
    --> Should the waferboard be replaced with plywood?
    --> Should I use OSB or another composites, in place of plywood?
    --> What grade(s) of plywood are within spec?
    --> Should I be using something like type 1 mastic to glue down the plywood?
    --> Or, should I use something like liquid nails, and use a 1/8" notched trowel to create an even glue layer?

  • Add a moisture barrier over unmodified thinset. Must this be 1/4" CBU, or would thinner layers, such as Ditra, or RedGard be sufficient??
  • I'm concerned about the transition height to bedroom and closets, and don't want to create a 3" or 4" "step" between the rooms (nor have to add 1.5" of flooring to the other rooms, either). What options minimize the height of the finished floor? (Again, remove the waferboard? ditra or redgard rather than 1/4" CBO?) I expect that I could build a 8" long, 1" high wooden ramp under the carpet at the bath entrance, but more than that will be too noticeable. I might have to add a layer of subfloor to the adjacent walk-in closet to balance that height as well. Dreading that.

Shower and Bath Surround issues:

  • The contractor used a Hardibacker 1/2" CBU to replace and construct the shower walls, after the original installation was demo'd (gypsum board, chickenwire, 1" floated mortar, and 4x4" white tiles). He screwed the CBU to the studs, and as far as I understand, that's an adequate installation. However, he used Redgard over fiberglass mesh for the joints, whereas Hardie requires unmodified thinset over mesh for the joints.

    Question 1: At this point, could I simply coat the entire shower and tube surround with Redgard? Or, do I need to scrap/sand to remove the Redgard at the joints, and install the thinset over the joints? I'm not sure how successful that would be.

    Question 2: The shower tub was a quality build by a local hotmop specialty company. The contractor extended the CBU to overlap the shower tub. I believe code calls for a minimum 2" overlap. The Contractor placed a ledger board as a starting point for tiling up the wall, but no smooth joint exists between the CBU and shower tub. How is this normally handled? Caulk? (In fact, on the bath tub side, there's a considerable gap between the hardie and shower tub - see last picture. Not sure how the contractor intended to deal with that. I expect that I'll have to rework the CBU to overlap further and seal that void.)


While I know that Hardie backer CBU properly installed, is supposed to form a waterproof barrier. However, for the cost of a gallon or two of Redgard, I'm tempted to coat the entire installation (assuming I use 1/4" CBU for the floor) in two coats of Redgard.

Intend to use Versabond for all travertine. I know I should pre-seal the travertine before setting it to prevent stains; I'll do it if I have time.

Thanks.

Kman 01-11-2015 03:52 AM

My understanding is that waferboard is just a cheaper version of OSB, and not something that I would choose as a subfloor. If you were installing ceramic tile, I would probably tell you to add a layer of 1/2" plywood and start tiling. However, you're planning on installing natural stone, and a very soft one at that.

Since two layers of plywood/OSB are required for stone, my inclination would be to remove what you have there and go back over the joists with 3/4" plywood followed by a layer of 1/2" plywood. Both layers should have a face grade of A, B, or C and have an exposure 1 rating. The 3/4" ply should be glued to the joists with construction adhesive, and secured with screws or ring shank nails every 8". The layer of 1/2" ply should be installed with screws or ring shank nails only, no glue, using the recommendations in this article to install it. That will give you the best chance at a successful installation, assuming your calculations on the joist deflection are correct.

SWB04 01-11-2015 04:50 AM

Quote:

Originally Posted by KMAN
"Since two layers of plywood/OSB are required for stone, my inclination would be to remove what you have there and go back over the joists with 3/4" plywood followed by a layer of 1/2" plywood. "

Thanks Kevin.

Can anyone provide me a reference that indicates that 3/4" OSB (or in this case, LP waferboard) with one layer of either 1/2" or 3/4" Plywood would not be sufficient for a travertine install? Or is the double plywood requirement based on personal experience and "gut feelings"? Must the two layers both be plywood? And, I presume that I could reduce floor height by using either two layers of Redgard or Ditra, versus the CBU for the floor isolation membrane.

I have to pull the CBU, so I suppose I can just cut between the joists with a "saws all" and pull up both the CBU and waferboard at one time. I'm a bit concerned about nicking the joists. I assume this would be R&R wall-to-wall, closet to vanity, tub and shower over to the bathroom, reaching joists as are exposed. I'm not going to touch the already prepared shower or bath tub; too much already invested there.

However, I'm preparing this home for resale (i.e. kids are gone, nearing retirement, etc.). I'm $1000's over budget in this already. I really don't want to tear up the entire bathroom subfloor, but if that's where I have to go, it's coming out today.

Thanks again.

cx 01-11-2015 08:50 AM

Scott, the Marble Institute of America (MIA) governs that installation and requires a double layer of plywood or OSB for any natural stone tile installation, regardless the joist spacing. Each layer must be properly, and differently, installed. Then you would install the tiling substrate of your choice and tile.

There are various combinations of subfloor that would satisfy the industry or/and specific substrate manufacturers, but starting with nominal 3/4" T&G material and adding nominal 1/2" exterior glue plywood with no face of grade lower than C would be my choice.

You'd then add the substrate of choice per that manufacturer's instructions.

But it's your house and your tile and your dinero and you can install over anything you feel comfortable with. With your joist spacing I would not install even ceramic tile without the second layer of plywood.

My opinion; worth price charged.

Pirate 01-11-2015 11:27 AM

Quote:

Originally posted by Chate'
OOPS! lol. I got half the attribution. Sorry, that irks me too (quotes without the names of the person who said it). Or maybe it doesn't irk you. . In any case, wouldn't you redguard over the joints after you've done the taping/thinsetting? (some of the comments here made me realize I didn't quite understand the handling joints with redguard during an installation)
__________________
Kontorsion
(Chate')
To answer your question about the Redguard. Redguard is a waterproofing membrane. Applying it only to the joints doesn't make the whole shower waterproof. To properly use it, he whole area needs to be covered with Redguard.

SWB04 01-11-2015 12:51 PM

Hi CX,

I spent "even more" time researching, and finally found a copy of the chapters in the MIA "Dimension Stone Design Manual" that applies to plywood subfloors and Travertine installations. I also found a MIA Q&A document which shed light on a few things.

http://marble-institute.com/dsdm_7-2...%207_2_web.pdf

http://marble-institute.com/dsdm_7-2...DM_7_2_web.pdf


My take is:
  • MIA still discusses two layers of "plywood or OSB" in the Q&A, while the guide seems to only recommend plywood. MIA does make one significant distinction in the Q&A. OSB and similar products aren't an issue for rigidity. The main concern is OSB expands at about twice the rate of plywood when wet. The existing subfloor is 23 years old, and for 23 years has supported a bathroom environment covered with nothing more than carpet and a pad. There has been no moisture penetration above or below the layer (nor in the tub or shower areas). Therefore, my conclusion is that while the existing 3/4" waferboard is not idea, it should adequately support the subfloor if overlaid with 3/4" exterior "C" or "C" plugged grade (per MIA standards). I'm not concerned about moisture or expansion at the base layer. If we have a plumbing leak that floods the second story floor to the point of damaging the waferboard, the we've got bigger fish to fry than worrying about the travertine floor.
  • MIA recommends 1.5" of plywood, e.g. two 3/4" sheets, versus 1.25", so I'll install one 3/4" plywood layer over the existing subfloor.
  • The MIA guide recommends expansion gaps BETWEEN the plywood, even tongue in groove. I knew that the boundaries of the installation required 1/4" gap, but I never dreamed that I'd be installing the plywood essentially unconnected with every other sheet. That's how I read this (see quote), and I really don't want to do this, since this is a structural layer. The guide also lays out in detail how the glue is applied (beads @ 2" intervals, not applied like mastic with a trowel), and everything else required - great stuff!

    Quote:

    Originally Posted by MIA
    "6.1.1 Plywood subfloors, including tongue-and-groove plywood, must be installed with a gap between the sheets to allow for expansion. Stagger all seams. All subfloor seams should occur over framing, with underlayment seams occurring approximately 25% into the span between framing members. Plywood should have the strength axis running perpendicular to the joist."

  • I'm going to install Ditra in unmodified thinset as my separation membrame for the floor, over hardi-backer (which I actually prefer), to reduce the finished floor height.

This still leaves open the questions regarding the shower and tub surround. I know that I can call Hardie for advice, and their customer service rep will simply quote "chapter and verse". There's no industry guide for resolving "substandard installation" other than ripping it out and starting over, and I don't think this is required. The Hardie was properly installed with glue and screws, and the joints are sealed with Regard and tape. As I said previously, since the Hardie is not truly a structural membrame, if I overcoat the shower and tub surround with Redgard my reasoning is that the installation will be watertight (e.g. reasoning that if Redgard over wallboard is supposed to achieve this, Redgard over Hardie should achieve the same). In other words, I'm not going to attempt to remove the Redgard and apply thinset to the joints of the shower; I'll leave them as is, and coat the entire installation.

So, I'm making a few compromises, but I believe that they are reasonable trade-off's to achieve the objective cost-effectively. If there's something I've missed in my logic, I appreciate the advice.

Thanks, all!

Kman 01-11-2015 01:13 PM

Scott, installing two layers of 3/4" ply over 19.5" spaced joists is a good thing. The less deflection you have between the joists, the better off you'll be, considering your choice of finished flooring.

Plywood manufacturers require gaps between the plywood sheets for good reason. Without those expansion gaps, you'll experience peaking at the seams, and in some cases you'll have sections of plywood lifting from the joists. Some products have the spacing built in along the tongue and groove edges, and some don't. Along the shorter edges, where the sheets will meet along a joist, you must leave 1/8" gap there. If you have new subfloor meeting old subfloor where there is no tongue and groove, it's important to join those pieces together by using some sort of material underneath, either a scrap of subfloor or a 2x4, etc.

As I mentioned earlier, a second layer of plywood installed over the subfloor should be installed without glue, unless you are prepared to trowel glue evenly over the entire subfloor. Beads of glue can actually do more harm than good by creating little voids between the plywood sheets where no glue exists. Trust me, installing the second layer with screws every 4-6" makes for a very solid substrate.

Also, there is no benefit to you in installing Hardibacker and Ditra on the same floor. In that application, they serve the same function and are therefore redundant. You would simply be adding more height to your floor. If you want to keep the height to a minimum, use Ditra over a proper subfloor.

cx 01-11-2015 02:35 PM

Scott, you'll find some contradictions between that MIA manual and the stone installation methods in the TCNA Handbook, which began to publish a few stone methods in, I believe, 2012. And you'll find some clerical errors in each, some of which have caused a good deal of confusion in past. Such as their requirement for substrates to be "level" to a specific tolerance when I'm sure they mean flat. And for the joist deflection in the TCNA saying L/360 is required when the MIA still requires L/720. You've gotta overlook some of that with an eye towards the intent and that's not always an easy thing.

You can find in the TCNA Handbook a published method for stone installation over wood framed subfloors using CBU, for example, that requires a first layer of nominal 5/8th" and a second layer of nominal 1/2" plywood. That method requires a maximum of 16" joist spacing, though. I think they would accept 1/2" over 3/4" over 19.2" joist spacing, but I can't prove that and Kevin's recommendation of two layers of 3/4" might be safer.

The method of gluing of the plywood layers with beads of construction adhesive I would take issue with and the ceramic tile industry actually has testing that indicates some small measure of uncoupling the tile installation exists when the second layer of plywood is mechanically fastened only to the first layer and not to the joists and definitely not glued in any manner.

Whole lotta things to consider and we'll always try to lead you down the most correct path. But if you find evidence you like better, you're certainly free to use that instead. :)

If you decide to use two layers of 3/4" plyoood, I'd very strongly recommend you pre-drill the screw holes in the top layer to prevent screw jacking.

My opinion; worth price charged.

by-eye 01-11-2015 04:27 PM

Scott, sorry for your troubles.
Your shower is built wrong.:gerg: It should have the studs furred out (plum), and a moisture barrier with the hardie properly overlapping your hot mop base, with no fasteners lower that 3 inches above the finished curb. :crap:
You might be able to bridge the gap with kerdi, but it wouldn't be proper.:x:
Since your selling, have you considered changing to ceramic tile? Will the toilet flange accept a new floor height? Are you prepared to undercut the doors and trim?

SWB04 01-11-2015 06:16 PM

Quote:

Originally Posted by by-eye

Since your selling, have you considered changing to ceramic tile?

Actually, I was checking my fire insurance and thinking more of "dynamite". :loaded:

Actually, I already have the materials, and the "standard" for homes in this price range around here is natural stone. We already have 1000 sql ft of travertine in our main rooms down stairs. The new installation matches that installation downstairs.

Quote:

Originally Posted by by-eye
Your shower is built wrong. It should have the studs furred out (plum), and a moisture barrier with the hardie properly overlapping your hot mop base, with no fasteners lower that 3 inches above the finished curb.

Are you saying that the bottom of the hardie should be plumb with the top of the hot mop basin?

I believe the studs are vertically plum with the bottom of the basin on the shower control and back sides. The Hardie (moisture barrier) extends over the hot mop base (not sure how far, though). The gap on the bathtub side of the shower needs some sort of resolution. I'm out of time this weekend, but I'll pull his ledger boards and get a closer look next week, and see how and if it can be fixed.

Nothing this contractor did was done correctly. I'm glad I stopped him when I did. Funny thing is, none of the 4 LICENSED contractors I interviewed and took bids from mentioned deflection, load, double plywood subfloors, and so forth. None of them were prepared to perform the installation consistent with industry standards.

Thanks.

cx 01-11-2015 06:25 PM

Quote:

Originally Posted by Scott
Are you saying that the bottom of the hardie should be plumb with the top of the hot mop basin?

The bottom of the Hardibacker should be plumb with the top of the Hardibacker, Scott, and the wall should be flat. That's important and if you don't have that condition, now's the time to fix it.
Quote:

Originally Posted by Scott
The Hardie (moisture barrier) extends over the hot mop base

One of your major problems is that you have no moisture barrier, and that's another of the things you really wanna correct.

My opinion; worth price charged.

Kman 01-11-2015 06:26 PM

Quote:

Originally Posted by Scott
The Hardie (moisture barrier) extends over the hot mop base (not sure how far, though).

Is there plastic or felt paper behind the Hardibacker? If there is, there would be no reason to use Redgard on the surface. If not, you should be aware that Hardibacker is not a moisture barrier. When installed without a moisture barrier behind it, then a moisture barrier, such as Redgard or a sheet membrane, should be used on the surface.

Lazarus 01-11-2015 06:28 PM

Isn't it amazing? The people out there that hold themselves up as a "Tile Technician" that, in reality, can't find their A$$ with both hands? :gerg:

"Industry Standards" be dammed. (Uh...I been doin' it this way for 30 years and I've had no problems...") Yeah, and HOW MANY of those "Thirty Year" projects have you checked on???? :bang:

Steve in Denver 01-11-2015 10:32 PM

Quote:

Originally Posted by kman
My understanding is that waferboard is just a cheaper version of OSB, and not something that I would choose as a subfloor.

I found this:

http://osbguide.tecotested.com/pdfs/en/tb103.pdf

which basically says that waferboard is similar to OSB but with all the pieces (wafers? strands?) randomly oriented whereas the OSB has a larger percentage oriented with the grain parallel to the long axis of the panel...

I'd like to know how they manage to make that happen...

Kman 01-12-2015 01:27 AM

Couldn't tell you about that.

Maybe with a pair of tweezers and a lot of glue? :D

SWB04 01-13-2015 12:34 AM

1 Attachment(s)
Quote:

Originally Posted by KMAN
"Is there plastic or felt paper behind the Hardibacker?"

Don't know. Doubtful. I filled the shower walls with a good quality insulation, but was out of town when the guy closed up the wall.


So, we demo'd the floor tonight.
  • Bad news: the guy painted Redgard on all the screws, requiring us to remove the RG from the wholes with a pick to be able to use the square drive bit to remove them.
  • Bad news: The guy followed standards, i.e. screws about 6" from each other; LOTS and LOTS of screws to remove. He also used an impact driver, and rounded off a bunch of the screws. He also counter-sunk most screws, burrowing them into the CBU (and leaving a bumpy surface as a result).
  • "Good News": The guy didn't believe in wasting glue on Hardibacker (see picture). Once the screws were removed, the CBU peeled right up.

I decided to compromise on my solution.

Floor:
  1. Layer 1: Existing 3/4" Waferboard
  2. Layer 2: 5/8" Plywood (per Hardie's spec), with 1.25" #10 CBU screws and Locktite PL 3x Premium Polyurethane construction adhesive (beads spaced 2" apart, per MIA's guidelines).
  3. Layer 3: Hardie 1/4" CBU, laid in unmodified thinset (skim coat, 1/4" notch), using the same 1.25" #10 screws, and filling joints and screw holes with thinset over fiberglass mesh tape. The Hardie will be set in the opposite direction to the plywood (there's no Hardie spec on this; just seems like a good idea), meeting all requirements (i.e. staggered joints, no four joints meeting in corners, etc.).
  4. Layer 4: 2 coats Redgard over everything (to guarantee a waterproof environment);
  5. Layer 5: Versabond and 1/2" Travertine.

Shower:

Jury's still out. The wall is "wavy" where the contractor installed the backer board, meaning that he didn't shim the walls to ensure a plumb fit. However, the wall itself appears plum from the top of the (adjacent) closet wall down to the shower tub. I'll ask the new installers coming in tomorrow if they want to try to float mortar work around the problem when laying the travertine, or rip out the CBU and start over. I suspect we'll keep the existing 1/2" CBU and fix the other issues.

Based on my experience removing the Redgard protected joints (1 coat only, I am sure), it's tough stuff, so I'm leaving the Redgard as is on the shower and tub surround joints. We'll apply unmodified thinset over the joints, just the same, to add some support. I was initially concerned that that the Redgard membrane would keep the thinset from sticking, but since mortar is applied over Redgard to install the tile, the mortar should cover the joints adquately. As I said earlier, I'll overcoat the entire shower and tub surround with Redgard anyway to ensure a watertight environment.

This is a less than perfect installation, but it's 10x better than where we were after the contractor bugged out.
  • It will be water tight, due to both Hardie and Redgard;
  • It will be rigid, with a 3/4" waferboard, covered by the 5/8" plywood plus 1/4" Hardie CBU. The joists are configured > L/720.

Thanks for the help. I'll post pictures if I get the time to take them.

Kman 01-13-2015 02:25 AM

You're correct in your assessment that it's a less than ideal solution. :)

One glaring problem I noticed is your plan to use 1 1/4" CBU screws to secure the 5/8" ply to the subfloor. You really shouldn't use CBU screws for that application, but even worse is that the screws aren't likely to have enough thread penetration to the subfloor. You don't mention the brand you plan to use, but sometimes the very tip of them don't even have threads, just a kind of pilot to get the screw started.

You should use a minimum 1 1/2" deck screws for securing plywood sheets together. 1 1/2" screws will completely penetrate the full thickness of the subfloor.

by-eye 01-13-2015 04:19 AM

You'd save a lot of time, money, and have a little less floor height if you just used ditra, and followed their instructions. And with what you saved, you could fix your shower. Any way...:goodluck:
Keep us posted.

SWB04 01-13-2015 04:39 AM

Quote:

Originally Posted by KMAN
"One glaring problem I noticed is your plan to use 1 1/4" CBU screws to secure the 5/8" ply to the subfloor. You really shouldn't use CBU screws for that application, but even worse is that the screws aren't likely to have enough thread penetration to the subfloor. You don't mention the brand you plan to use, but sometimes the very tip of them don't even have threads, just a kind of pilot to get the screw started."

Backer-On 800-Pack #10 x 1-1/4-in Cement Board Screws

What's wrong with CBU screws?

3/4+5/8=1.375 " versus 1.25" screw

Sunk flush with the CBU, they should penetrate the full 1.25". Should the screws be popping out the bottom of the substate? I thought the top sheet of plywood wasn't supposed to be secured to the joists. I'd think that 1.5" would penetrate the joists in some situations.

Any how, I've got some gold zinc plated drywall screws about 1.5" which have worked pretty well for securing wood in all sorts of situations; I can use those for the plywood layer.

SWB04 01-13-2015 04:44 AM

Quote:

Originally Posted by by-eye
"You'd save a lot of time, money, and have a little less floor height if you just used ditra, and followed their instructions. And with what you saved, you could fix your shower. Any way..."

I looked at using Ditra, and it looked like the roll I'd need would run several $100 (at least at the big box stores). The backerboard + Redgard won't cost more than the Ditra, and neither of those products are cheap, either.

Thanks.

SWB04 01-14-2015 11:25 AM

Question: How do you know if you hired the right tile guy?

Answer: He finds all the other guys mistakes (and quotes standards to back up his critique).

Just found out that the shower faucet is out of plumb. Add one more thing the licensed expert tile contractor forgot to check. We'll go through the closet drywall to resolve the problem without ripping up the shower CBU, but it's "just one more thing". (My wife says "let it go", but I'm getting angrier at this guy every day. I am BLESSED to have gotten rid of this guy before he "finished" the job.)

The new guy's young, probably second generation Hispanic ++, smart, very professional, and clearly knows what he's doing. He is **UNLICENSED** :wtf: (but will be sitting for the contractor's test this summer). I understand all the risks. He's taking on this as a side job at the request of a friend.

I'll let you guys know how this installation progresses, but I think we'll be done by Saturday. We demo'd the 1/2" Hardibacker yesterday, installed the 5/8" plywood (note to KMAN, with 2" galvanized wood screws), and 1/4" Hardiebacker in thinset with 1.25" CBU screws. The floor is clearly a lot more solid. It's like walking on rock. Redgard is going on now. So, all in all, I'm about $1800 over budget on this project, due to work that needed to be redone and additional materials required.

++ (Why did I bring race into this? Because "Eddie the Contractor" said "Go hire yourself a Mexican ..." as he walked out the door. So, I did. ;)

Kman 01-14-2015 01:50 PM

Quote:

Originally Posted by Scott
Why did I bring race into this? Because "Eddie the Contractor" said "Go hire yourself a Mexican ..." as he walked out the door. So, I did.

You took his advice again? :D


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