# Scratch coat on cement board...



## Tscarborough

No scratchcoat over board, thinset directly to it for adhered veneer.


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## TheItalian204

sitdwnandhngon said:


> I have pounds of EIFS on my clothes, I am convinced that the stuff has some serious lasting power after all the washings its held up through.
> 
> .


That is true,but its a contraversial topic...I have seen holes in acrylic from where it was knocked with foot or a soccer ball etc...

but properly done acrylic or sand/cement will give you same effect.

With sand/cement stucco you have to watch more things compared to acrylic.

With acrylic you need proper moisture management. Now that is sometimes PITA to sell to customer...


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## dom-mas

I could see thinset sticking better to cement board since it seems to use a chemical bond rather than a mechanical bond (I don't really do tile so I'm just guessing here) but for a product like cultured stone, where there is such a rough back, would there be enough surface contact to make a decent bond to the unit?


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## TheItalian204

dom-mas said:


> I could see thinset sticking better to cement board since it seems to use a chemical bond rather than a mechanical bond (I don't really do tile so I'm just guessing here) but for a product like cultured stone, where there is such a rough back, would there be enough surface contact to make a decent bond to the unit?


I have done maybe 6 stones total with thinset(ran out of mortar,didnt wanna drive to vendor,had bag of thin sitting in van) and I gotta say I hate it...thinset has peanut butter consistency,its hard to handle compared to simple mortar...I can see how what Tscar is saying is plausible but I still wouldnt want to do it because of thinset's consistency.

Not to mention that you still getting reg. mortar anyway because you gonna be grouting if you are wet-stacking.


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## Tscarborough

Quit buying cheap ass Home Depot thinset. The good stuff has a 45 minute board life in the heat, is high-build and highly modified, and you even have time to adjust the stone before it grabs.


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## TheItalian204

Tscarborough said:


> Quit buying cheap ass Home Depot thinset. .


Who told you I am buying HD thinset?


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## dom-mas

what about the lack of surface area on the back of cultured stone, eldorado stone etc.. i can def see using it on "realstone system" or any natural stone with a saw cut back but the rough back of culutured stone, there's less against the wall than not


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## Tscarborough

Follow manufacturers installation instructions for the thinset, not the stone, since they warrant the bond.


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## dom-mas

Tscarborough said:


> Follow manufacturers installation instructions for the thinset, not the stone, since they warrant the bond.


Interesting. Square notch or V notch?


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## Tscarborough

Margin, since they require full coat on the stone, not the board.


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## dom-mas

Tscarborough said:


> Margin, since they require full coat on the stone, not the board.


What, just glop it on? or a thin smear over everything?

I've used PL many times before for fireplaces, I could climb the wall the next day, but never thinset.


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## Tscarborough

http://www.laticrete.com/dealers/products/anti-fracture_crack_supression/productid/54.aspx


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## dom-mas

oh, I see. extra steps required and about the same result as a mortar with acrylic additive. That installer has no idea bout masonry, that's obvious.

I think i'll keep staying away from thin veneer except for fireplaces.


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## Tom Struble

actually the stuff was invented to repair masonry buildings damaged in ww2


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## TheItalian204

dom-mas said:


> oh, I see. extra steps required and about the same result as a mortar with acrylic additive. That installer has no idea bout masonry, that's obvious.
> 
> I think i'll keep staying away from thin veneer except for fireplaces.


you dont do any cultured besides fireplaces?how come?


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## dom-mas

I do, but i try to price them not to get them. I don't like it and I don't trust it. I don't like that I can't cut it without having to hide the cut. I do fireplaces because they're quick and good indoor winter work or weekend jobs


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## TheItalian204

dom-mas said:


> I do, but i try to price them not to get them. I don't like it and I don't trust it. I don't like that I can't cut it without having to hide the cut. I do fireplaces because they're quick and good indoor winter work or weekend jobs


If you talking about quality of product,then yes I dont trust them.

But I find it to be quick cash...it is great way to do some winter work though I agree...


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## dom-mas

TheItalian204 said:


> If you talking about quality of product,then yes I dont trust them.
> 
> But I find it to be quick cash...it is great way to do some winter work though I agree...


No, i don't trust mortar to stick product on the wall for a lifetime. To me mortar is a gasket between different surfaces, not to be treated as a glue. That's why I like using PL. But on a bigger job, PL would be very expensive, which was why I was hoping to get excited about that lactite stuff. i've been using bagged parge mix lately and I trust that quite a bit more than regular type N but at $5 a bag and it only covers maybe 10sqft it can get expensive as well. Basically I don't know enough about it, never taught just picked it up kind of, so that makes me nervous. I've been in business about 10 years and haven't had any call backs, I feel like cultured stone would start.


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## TheItalian204

dom-mas said:


> No, i don't trust mortar to stick product on the wall for a lifetime. To me mortar is a gasket between different surfaces, not to be treated as a glue. That's why I like using PL. But on a bigger job, PL would be very expensive, which was why I was hoping to get excited about that lactite stuff. i've been using bagged parge mix lately and I trust that quite a bit more than regular type N but at $5 a bag and it only covers maybe 10sqft it can get expensive as well. Basically I don't know enough about it, never taught just picked it up kind of, so that makes me nervous. I've been in business about 10 years and haven't had any call backs, I feel like cultured stone would start.


It happens but I would think I would be more worried abot anything else but cultured stone...

I would suggest looking into SPEC-MIX line they have some good products...parge mixing you buy for 5$ a bag is essentially same stuff...I add weld-crete to mix when I lay cultured...that does good trick too..


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## Tscarborough

Do the kind of work you want to do, but if you are going to do it, do it right. Lath over cement board is stupid, as is scratching board. If you are going to stick concrete to concrete board, then do it with a product engineered for that purpose.


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## TheItalian204

lemonbomber said:


> Who or what is OP?


OP is you sir and let me justify my response about your ego.


Nothing good can come out of leaving eveerything way it is.

you get 10 shots at it way you did it. 1 time out of 10 it will miraculously hold. 4 times out of 10 whole thing will come down eventually whether partially or all together and that will be last time you hear from your buddy. 5 times out of 10 it will come down partially or all together and you will have lawsuit on your hands from guy who forgot he was your buddy.

As many more besides myself mentioned above. Keep your fingers crossed.


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## dom-mas

OP, similar to OG but not quite.

original Poster


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## Stone

I don't know why lemonbomber's scratchcoat didnt take but there is nothing wrong with thin stone on cement board. I have posted this here before but here it is again: This job is about six years old and is sawn thin veneer over cement board, outside, in a freeze/thaw climate, and everything is still fine. I used a type s with a bonding agent, wet the cement board, scatched coated wet just ahead of laying the stone.


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## TheItalian204

Stone said:


> I don't know why lemonbomber's scratchcoat didnt take but there is nothing wrong with thin stone on cement board. I have posted this here before but here it is again: This job is about six years old and is sawn thin veneer over cement board, outside, in a freeze/thaw climate, and everything is still fine. I used a type s with a bonding agent, wet the cement board, scatched coated wet just ahead of laying the stone.


I think you mentioned at least 2 steps that OP missed


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## lemonbomber

Lets if I can get an "after" photo here.....


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## JD3lta

^^If that's a real picture I quit. What was it the first day?


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## TheItalian204

Lol I honestly did not want to say anything,but man,this is rough.


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## Tscarborough

I like it if he did it like that on purpose.


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## TheItalian204

Tscarborough said:


> I like it if he did it like that on purpose.


I considered that possibility but you can still do it if you line stones up straight.


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## lemonbomber

I actually did it this way on purpose. Reason for it was that I thought to have straight lines for more than one course would create instability. Plus I liked the look of a more rustic wall. If I had wanted everything perfectly straight and uniform I would have gone with brick or cut stones.
Still deciding whether to do something with any of the spaces between rocks. Such as grouting mortar in there or small stones or just leave it as is. His wife is deciding. 
Any suggestions?


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## TheItalian204

Thin natural stone veneer is not much heavier than any other stone so I doubt it would create instability.

You wont be able to shove small rocks in those gaps. If you have to do something with them,just grout them.


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## JBM

When people say im op, that usually means overpowered


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## JBM

The left side has some issues ?


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## JD3lta

Lemonbomber, I don't usually critique other stonework. I always say that faux stone should replicate the real thing, and people usually don't care.. With your permission I would like to share a copy of your photo with some marking I put on it.. thanks:










And IMO(In my opinion) I think the spaces as joints are fine there's nothing to do about it now- it's got the dry look. That's all I got..


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## superseal

Don't let Bytor see this thread...He'll have a friggin coniption :laughing:


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## TheItalian204

I dont like the color of stuff either...its likes been weathered somewhere in box for a century.


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## dom-mas

TheItalian204 said:


> I dont like the color of stuff either...its likes been weathered somewhere in box for a century.


I doubt the installer had much effect or influence on the colour. It is what it is, rustic. Not my favorite but i didn't pay for it. So long as the homeowner is happy and the stones stay on the wall, who cares.

As an aside. I was walking the dog yesterday and on an old stone warehouse in the neighbourhood (now a museum) there are stack joints 16" high that have 3 or 4 stones on either side. Rustic


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## dakzaag

JBM said:


> The left side has some issues ?


IMHO which ain't so humble, I really can not distinguish the left from the right. Its all pretty rough, but I question if that stone is designed to be a dry stack. 

Looks to me like it is irregular and should have been laid with a pretty big joint to help set them level. The stone is rectangular in shape so it should have followed basic masonry rules, like one on top of two... that sort of thing. 

I think the only stone that really is hard to keep level and plumb is river stone split face. It's round and pointy and ya kinda got to throw it against the wall and hope it sticks. 

The pic with the marks all over it like my third grade grammer teacher shows some of the basic errors. 

Not worth tearing out mind you, but if you really want to test it, grab a hammer and a crow bar and attack the biggest stone on there. If it pops off after one or two hits, you better keep chiseling. On the other hand if it takes an aggressive beating to get one loose, then it will be fine as is.:thumbsup:


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## JBM

dakzaag said:


> IMHO which ain't so humble, I really can not distinguish the left from the right. Its all pretty rough, but I question if that stone is designed to be a dry stack.


The left is the hand with the thumb on the right :thumbsup: like in this pic


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## qbhome

Stone said:


> I don't know why lemonbomber's scratchcoat didnt take but there is nothing wrong with thin stone on cement board. I have posted this here before but here it is again: This job is about six years old and is sawn thin veneer over cement board, outside, in a freeze/thaw climate, and everything is still fine. I used a type s with a bonding agent, wet the cement board, scatched coated wet just ahead of laying the stone.


Hi Stone, will this work fine for cultured stone? Which type s and bonding agent did you use? I like the work you did, btw.

Also is this the order you did this in? 
1) wet cement board then applied scratch coat
2) applied stone with what motar? with the type s and bonding agent?

When I was reading your post I thought you appled the scratch coat wet and just laid the stone on that but that can't be right.

I know this thread is old but hope you and others that contributed here are still active. I hope to hear from you and thanks in advance.


To OP, stones still in place?

To others, I might go with tile thinset for cultured stone for an exterior put if that is way more expensive than what member stone has done then I might just go with stone's method.

If you ask why cultured stone because its cheaper for me. lol @ 2 dollars a sq. ft.


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## qbhome

Stone said:


> I don't know why lemonbomber's scratchcoat didnt take but there is nothing wrong with thin stone on cement board. I have posted this here before but here it is again: This job is about six years old and is sawn thin veneer over cement board, outside, in a freeze/thaw climate, and everything is still fine. I used a type s with a bonding agent, wet the cement board, scatched coated wet just ahead of laying the stone.


Hi Stone, will this work fine for cultured stone? Which type s and bonding agent did you use? I like the work you did, btw.

Also is this the order you did this in? 
1) wet cement board then applied scratch coat
2) applied stone with what motar? with the type s and bonding agent?

When I was reading your post I thought you appled the scratch coat wet and just laid the stone on that but that can't be right.

I know this thread is old but hope you and others that contributed here are still active. I hope to hear from you and thanks in advance.


To OP, stones still in place?

To others, I might go with tile thinset for cultured stone for an exterior put if that is way more expensive than what member stone has done then I might just go with stone's method.

If you ask why cultured stone because its cheaper for me. lol @ 2 dollars a sq. ft.


Tscarborough said:


> http://www.laticrete.com/dealers/products/anti-fracture_crack_supression/productid/54.aspx


I like this a lot. Apply their primer of 2 coats and use their special mortar with stone just on cement boards and the warranty is a bonus. 

Someone told me that Large Format Tile Thinset Mortar such as LFT or Ultra Light both by Mapei will do the job as well. Which you can buy from a tile store. Though no primer just straight to the cement board. What are your thoughts on that?


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## dom-mas

I haven't done thin stone against cement board exterior but what I have done interior is with a brush wet the cement board in the area I'm about to stick a stone, butter the back of the stone with thinset and scratch the back with a notched trowel, or pile on cement with lots of bonding agent, then push the stone on the cement board until cement oozes out. If the cement board flexes at all, it's no good. I can say that when i had to replace a couple stones because they interfered with how a drawer pulled out, I had to chisel them out. It was tough to remove them


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## Stone

qbhome said:


> Hi Stone, will this work fine for cultured stone? Which type s and bonding agent did you use? I like the work you did, btw.
> 
> Also is this the order you did this in?
> 1) wet cement board then applied scratch coat
> 2) applied stone with what motar? with the type s and bonding agent?
> 
> When I was reading your post I thought you appled the scratch coat wet and just laid the stone on that but that can't be right.
> 
> I know this thread is old but hope you and others that contributed here are still active. I hope to hear from you and thanks in advance.
> 
> 
> To OP, stones still in place?
> 
> To others, I might go with tile thinset for cultured stone for an exterior put if that is way more expensive than what member stone has done then I might just go with stone's method.
> 
> If you ask why cultured stone because its cheaper for me. lol @ 2 dollars a sq. ft.
> 
> I like this a lot. Apply their primer of 2 coats and use their special mortar with stone just on cement boards and the warranty is a bonus.
> 
> Someone told me that Large Format Tile Thinset Mortar such as LFT or Ultra Light both by Mapei will do the job as well. Which you can buy from a tile store. Though no primer just straight to the cement board. What are your thoughts on that?


t

I used Quikrete CSC-4 mortar and Acryl 60 bonding agent. I have used this mix to put sawn thin veneer on a ceiling and it worked really well.
On cement board I wet the board and then put on a scratch coat in the area where I am working, then mortar the stone (make sure the back of the stone is clean and apply mortar to it then scrape it right off and then apply mortar again) and apply it to the wall.


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## qbhome

Stone said:


> t
> 
> I used Quikrete CSC-4 mortar and Acryl 60 bonding agent. I have used this mix to put sawn thin veneer on a ceiling and it worked really well.
> On cement board I wet the board and then put on a scratch coat in the area where I am working, then mortar the stone (make sure the back of the stone is clean and apply mortar to it then scrape it right off and then apply mortar again) and apply it to the wall.


1) Whats the ratio of the mortar mix and acryl?
2) How long do you wait after applying the scratch coat before putting mortar and stone on it?

I see some method of wetting the cement board and also the back of stone before mortar but I think your method of mortar the stone and scrape it off then applying mortar is like wetting the back of the stone.

3) Do you experience lots of sag or grip? Do you have to hold it in place for a little or use brick ties?


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## qbhome

@Stone, have you ever used a Large Format Tile Thinset Mortar such as LFT or Ultra Light both by Mapei on cement boards with stone?

Would you say dry stack is more forgiving in having to stay flushed/plumed to line? also figure mortar joint isn't necessary for this stack.

I'm only doing a half wall of stone (bottom) and vinyl siding (top) to just the front of my house, the other sides are just siding but I feel that can get complicated since I'm doing that to just the front of the house and not sure if I need corner pieces then cut it off into a vertical line on the adjacent wall and attached a j channel to continue with the vinyl siding or..

just do the half wall on front with no corner pieces and have it extend to just the vinyl trims/j-channel?

do you use backer rods in this kind of masonary. if so, i'm not sure how to install that but i'll have to search more online


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## CanCritter

thinset ..spray backing and have at it...lath needs to be attached..in doing so are perferateing the backing which will lead to issues down the road with leakage..lath is the worst thing to do


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