Premium Unmodified Thin set mortars

[Timalev]

After attending the JB class in Schluterville last week I came away with answers to a lot of questions that I had. Although I asked, I still never got a straight answer to the question...what IS a premium modified thin set mortar. The reason I ask is in regards the the big orange box store. They sell DITRA, and they sell unmodified thin set, Custom Blend to be exact. It is advertised as an economy grade....what the hell is economy grade? and why is it the only unmod they sell? Is it good enough for DITRA,?

According to Paul (last name escapes me) who is the HD rep for Schluter, he says "it's good enough but it leaves no room for error"...huh? I understand that in most cases you have to read the directions and mix mortar according to manufacturer specs. Most of us just pour in water and dry mix..give it a whirl and look for the texture to be just right after slaking. Or if you are a real die-hard you mix to taste. If Custom blend is a "marginal" mortar, then why reccomend it to homeowers to use when they buy DITRA at HD? Lord knows Joe homeowner doesn't always follow directions.

The MSDS on Custom blend states that it had 15 to 25% portland to weight with the rest bieng silica, quartz and crystaline (?) etc. The MSDS on Kerabond states that the ratio is 15 to 40% with the rest being Quartz, Tricalcium aluminate, calcium sulfate and Magnesium oxide fume. What are these other compounds? Do they make up what we should call a premium thin set mortar? Also, shear bond strength after 28 days for Custom is 195, Kerabond is 170 to 190. Seems to me that Custom performs better?

My point is, almost any unmodified mortar will meet ANSI spec 118.1 and that's all the install handbook says. However, veberbally, Schluter reccomends a "premium" grade. Waht is a premium grade undmodified mortar??
Anyone Know??

[tileguynky]

Tim, I came away from the class with the premium unmodified to have a portland content that will be close to 50%. The more portland it has, the more premium it will be. Locally, I was told by a local Daltile store that the Custom Blend was not a premium mortar and that is why the only Mapei they stock is the Kerabond. I was always under the impression that the Custom Blend and the Keraflor were both basic thinsets. Good for ceramic tile going onto a concrete slab or cbu. I do remember Andy saying to stay away from the Keraflor. I do not know if this is any help, just my 2 cents.

[Timalev]

There is no manufacturer (that I am aware of) that states their mortar is even close to 50% portland average. There has to be a more clear explanation.

[tileguytodd]

Kerabond is A Premium Dry Set..........Better grades of aggregates and a bit stronger mix from what i understand........Works great, In fact, I am Using it now on current job over Ditra...........Havent tried the ditra set, never saw a need with Kerabond available most places.......Costs a WHOLE lot more than Most, Worth a whole lot more than most

[ISLAND TILECRAFT]

What about customs multi set white?It states that its modified but you must use additive for plywood installs,that tells me its probably in the middle of a good mod to a non mod and the price is good at $12.00 a bag.
Any one know if this is legal for use on ditra??And thats a good point about what thinset to purchase for dita or kerdi if your only access is depot.
My supply house only carries tec sturdi set 335 in gray and i like white,they dont carry much of the un mods these days because no one buys them anymore.

[Timalev]

I was reading up on Mulit-set today. It's modified...how much..who knows. Schluter says unmodified so my vote is no you shouldn't use it. If custom blend is no good...you would think that Schluter would have a rash of failures on it's hands. HD is so big, you would think they would cover thier butts by carrying a premium dry set. No?

[deepwater]

Tec Sturdi-Set has always worked well for me

[Timalev]

I've used Sturdi-set too and it appears to perform no better than Custom blend according to TEC's test data..

[The Kid]

Laticrete 317 white, when it comes to price and performance, it cant be beat IMHO.

[Brian in San Diego]

Tim,

That's part of the problem with big box stores in general...they want the cheapest price. Custom Building Products ceased manufacturing any decent unmodified thinset over a year ago...maybe two. Prior to that they manufactured three drysets CustomBlend, MasterBlend and PremiumPlus. I believe the PremiumPlus would have fit the bill for use over Ditra. Even the Lowe's around where I live have stopped carrying KeraBond and now only carry KeraSet.

I think you really need to find a supplier who carries the premium stuff. I wouldn't use CustomBlend on a bet.

Brian

[Timalev]

Never said I use the stuff. I'll go out of my way for other options until Schluter ok's it. Would be REAL convenient though.......

[Saldibs]

Tim, I came away from the class with the premium unmodified to have a portland content that will be close to 50%

Tim I came away with the same thing as Greg. I always use ditra set so I don't have any issues. By the way will be using the Ditra XL for the first time this Friday.

[Jason_Butler]

I've always used Versabond - even for Ditra. It is "slightly" modified and the price is right.

JB likes it for Ditra - that's all the assurance I need

Jason

[Timalev]

Sal ! Good to hear from you. I'm installing 500 foot this week myself. I don't have a local supplier for Ditraset. I have to order it in advance. It's more expensive than Kerabond so at this point, it's not a viable option.

Versabond is STILL a modified mortar. The only way I use it is if I skim coat the DITRA first and set the next day.

[custombuilt]

I've used versabond for ditra too. But after the class I was leaning away from it. I however was wondering if any mortar that I can buy at lowes would suffice. So what if I use customblend and add a couple cups of pure portland to it?