NTCA Technical Committee

[Tiger Mountain Tile Inc]

I know there was some progress made on medium bed mortars and a new official category but didn't see anything about that in the minutes. That must have been a different committee?

[cx]

Re: Post 15:

3. Part of the problem cited with using rapid set mortars with TPT was their large size and the actual logistics of keying in, spreading, and notching both the substrate and the tile and putting the tile in place quickly enough.

4. Jan was pointing out that the size of the TPT, especially over membranes, can result in the polymers in the bonding mortar starting to dry from the outside edges and creating a narrow border, or halo, of such dried mortar around the perimeter of the tile/panel/sheet and the center portion taking much, much longer to dry, if ever it actually does in some circumstances. And she was concerned about the installer's liability if that caused a problem with the installation.

Re: Post 16:

Jim, there was some discussion of that in the MMSA meeting also held at TSP.

[eurob]

Re: post 17

3. This is from a practical aspect POV . Were there any technical ones discussed ?

4. She is quite right about being concern about the liability , I think . Let's say you do pretty much everything by the book , you cannot control how the humidity is dispersed through out the curing process of the mortar.
Then the rapid setting comes in play ....maybe one with long open time 1-2 hours and sure cure at a specific time frame -- 12h-- could be the answer .

[cx]

Roberto, please read post #12 about cure time.

[tilemanct]

I think Roberto hit the nail on the head for the TPT setting material. I never understood why the major thinset companies could not come up with a slower setting rapid set material.

[Art of Stone]

Originally Posted by TPT

Hightower said that it is possible to get the desired 95% coverage, but the only way to get an accurate measure is to wait until the mortar has cured before checking. He also said that Mapei’s newest mortar can guarantee that the 95% minimum will be reached.

It is absolutely possible to get the 95% coverage but this has to be done by the practices of the contractor; the mortar alone can't guarantee anything.
I do side with Hightower about checking for the coverage; short of maybe ultrasound and that is not very practical.

As CX stated, the issue with Rapid Setting Material is the open time. I feel extending the time before traffic is allowed on the installed material, is the easy solution to using typical cementious materials.

As per the wash lighting discussion, the lippage during installation is the primary factor; not the type or position of the lighting. Employ and properly use a lippage control system, mechanically remove the lippage during installation and issues resulting from lighting, will be drastically curbed or removed all together.

[John Bridge]

Can't answer all your questions, Roberto, but the rapid set issue is pretty simple, even to me. We're dealing with huge sheets of porcelain with which mortar needs to be troweled onto the setting surface and back-buttered onto the back of the piece. It's tough enough using regular thinset to accomplish this without getting an overglaze (skinning over). Rapid set is too, well, rapid.

[Brad Denny]

For 95% coverage AND reasonable curing properties with TPT, there are chemisty technology needs that are beyond my mind. Working with mortars available now I can envision better vibratory tools to help set the tiles. It seems the greatest concern is obviously floors, where manufacturers are looking for installers to say "yeah, we can do that", but are hearing "no, we're scared". Is it possible to look at ways to flood the floor and fill any possible cavaties with a liquid, similar to structural fixes to footers and piers?

[tileaz]

My most serious bone to pick with all the manufacturers is the coverage issue. When you look at most, if not all of the literature from mortar and tile manufacturers it states that 100% coverage is wanted not 95%. This 95% coverage is a false argument. The whole context of my question dealt with trying to attain maximum coverage on a 5x10 sq ft. piece of thin porcelain here in Phoenix. My point being is how can my people trowel out 50 sq ft of mortar on the floor or wall(interior and especially exterior) and 50 sq ft of mortar on the tile required by the "zipper system" without my mortar skinning over? We cannot. I was told to mix my mortar "wet". Any and I mean any manufacturer can tell you that 95% is attainable, but is that on jobsite conditions? How about here in Phoenix where I work and live(my bias) where this summer we tied our record low humidity at 2%. What is my point in this diatribe? I truly believe we can create a standard for thin porcelain if we limit the size of the material, maybe 1x1 meter, maybe 1/2x1 meter. We can start off conservatively until the mortar manufacturers catch up. I also absolutely believe that vertical installation exterior of this material is a gamble. We have not seen any data from the manufacturers regarding thermal expansion and contraction of the tile.

[tileaz]

Ernie, I disagree with you about the positioning of the lighting. As is seen in the NTCA Reference manual, light positioning aggravates or helps lippage issues. It's great to say lippage systems can help reduce lippage but how do these systems reduce inherent warpage of the tile on an offset installation? What was asked in the committee was a better way to show wash lighting to an owner or GC on the jobsite, I personally do the same on my jobsites. I do agree it is an installation issue, but again that is why we wrote language into ANSI about mandatory mock-ups when there could be an issue with excessive lippage.

[Art of Stone]

Inherent warpage IS reduced when using a lippage control system. The amount of reduction will vary by tile size and shape and/or, lippage control system used.

If you put two tiles face to face and see a gap on the ends, pinch the ends with your fingers and see if you can bring them together, flat.
If you can do it with your fingers, you can do it with a lippage control system.

[Art of Stone]

Originally Posted by James

My point being is how can my people trowel out 50 sq ft of mortar on the floor or wall(interior and especially exterior) and 50 sq ft of mortar on the tile required by the "zipper system" without my mortar skinning over?

You can James.
When I received my certification for installation of Laminam by Crossville, the class participants installed 5 tiles in roughly 1 hour and 20 minutes.

If I recall correctly, each measured 3'x9'. Two were installed on a wall and three on the floor.

This was not a fast pace installation by any standard. There was a lot of talking and training during the installation, which of course slowed progress; but was necessary for addressing each issue as we went along.

We removed the floor installation the following day and all were satisfied with the coverage we attained.

It really boils down to understanding how this material needs to be handled, installed, and the proper tools for doing so.

I will say, a one man gig would face a serious challenge installing anything larger than 3'x3'. With an adequate work force that is properly trained and equipped, it is a pretty straight forward installation.

[tileaz]

Ernie, all of my installers are CTEF certified. We have a tremendous amount of experience in the last 31/2 years of installing thin porcelain. All of the things I have learned and put out are based on my people's experience on actual thin tile installations, these are not my theories. Again, let me reiterate that my place of business is in Phoenix, at no time do we ever spread 50 sq ft of mortar out before we install anything. We can agree to disagree, that is fine, but I will have to defer to my surroundings and to jobsite conditions.

[eurob]

Originally Posted by Cx

Roberto, please read post #12 about cure time.

Kelly, if you want to take an answer '' as best answer '' , then you just tell it , here is what you guys should know and do .

As far as I am concerned , Steve is representing CBP or .... maybe he speaks for all the mfgs , but I do not know . He should really explain how the rapid setting mortars are curing forever .... I've seen ones which in 12hours are done curing , takes a little longer under submerged conditions , but it does cure , not 28 days or indefinitely .

I thought this thread is open to '' debate'' , maybe I am wrong.

[eurob]

Originally Posted by John Bridge

Can't answer all your questions, Roberto, but the rapid set issue is pretty simple, even to me. We're dealing with huge sheets of porcelain with which mortar needs to be troweled onto the setting surface and back-buttered onto the back of the piece. It's tough enough using regular thinset to accomplish this without getting an overglaze (skinning over). Rapid set is too, well, rapid.

Originally Posted by eurob

Then the rapid setting comes in play ....maybe one with long open time 1-2 hours and sure cure at a specific time frame -- 12h-- could be the answer .

I could only give my opinion of what it needs for those TPT to make them work .

And the over glaze ....well I think the problem is not there , even if it is skinning . Fresh mortar on the skin of another same mortar should be fine .
The problem is that one side is starting to stiffen and the other is fresh . Then the next piece may be even worse if you use the same batch mix.
The result is lippage .

With an extended open time , the chemical process doesn't take place for a while or at least gives you more time to work '' normally '' . Other factors will affect the curing process as well.