Contractor Talk - Professional Construction and Remodeling Forum banner
Cancel
Create thread New Forums

Scratch coat on cement board...

Jump to Latest
41 - 60 of 86 Posts
Discussion starter · #42 ·
Just for the record, I am using real stone that has been veneer cut. Product put out by Quarry Cut. Much better feel and appearance than cultured. Very smooth backs from the diamond blade saw that cut them.

Building a dry stack wall but we may have to grout in between some spaces that I can not get a real tight fit with the stones.

The manufacturer and vendor recommended S mortar for the scratch coat and to stick them up.
 
#47 ·
If laticrete warranties the bond then that's pretty good. There is a product at Home depot around here that is a mortar specifically for laying up thin veneer. Never looked at the specs or warranty since it's almost $20/bag (much less I'm sure in US). Maybe worth looking into also.
 
#48 ·
dom-mas said:
If laticrete warranties the bond then that's pretty good. There is a product at Home depot around here that is a mortar specifically for laying up thin veneer. Never looked at the specs or warranty since it's almost $20/bag .
Click to expand...
as in thinset or reg mortar?
 
#50 ·
I'm surprised the thin veneer supplier recommends tile backer as a suitable backer. Sure, it will work with an expensive thinset, but lath is far easier IMO. Just need to plaster the day before with Type S and a v-notch trowel, and add a small amount of bonding agent to the bedding mortar. As for what to do now? Not sure to be honest, as I take it you laid the joints in with the stone right away, and some of the stone is still loose??
 
#51 ·
It is probably Spec-Mix. They make a polymer modified mortar for adhered veneer, but I couldn't make it work on hardi-backer, even with stacked-stone (pro-fit type). It did work fine on adhered natural stone over hardi-backer though.
 
#52 ·
jomama said:
I'm surprised the thin veneer supplier recommends tile backer as a suitable backer. Sure, it will work with an expensive thinset, but lath is far easier IMO. Just need to plaster the day before with Type S and a v-notch trowel, and add a small amount of bonding agent to the bedding mortar. As for what to do now? Not sure to be honest, as I take it you laid the joints in with the stone right away, and some of the stone is still loose??
Click to expand...
I think only the scratch coat has come loose, no loose stone yet. But that was yesterday, today is a new day.

It's raining rocks, Hallelujah, it's raining rocks.
 
#53 ·
Tscarborough said:
It is probably Spec-Mix. They make a polymer modified mortar for adhered veneer, but I couldn't make it work on hardi-backer, even with stacked-stone (pro-fit type). It did work fine on adhered natural stone over hardi-backer though.
Click to expand...
Product you talking about runs for about 12$ with tax around here,so I doubt it would be 20+tax in Ottawa,but you never know :blink:
 
#54 ·
dom-mas said:
I think only the scratch coat has come loose, no loose stone yet. But that was yesterday, today is a new day.

It's raining rocks, Hallelujah, it's raining rocks.
Click to expand...
I've had culture stones hit me before, but never NTV. Ouch. Honestly, I have a hard time believing that some of the scratchcoat is only peeling where he hasn't laid stone yet. Not trying to call the OP a liar, but the scratchcoat may be weak on the lower stone already laid & he just doesn't know it.
 
#55 ·
jomama said:
I've had culture stones hit me before, but never NTV. Ouch. Honestly, I have a hard time believing that some of the scratchcoat is only peeling where he hasn't laid stone yet. Not trying to call the OP a liar, but the scratchcoat may be weak on the lower stone already laid & he just doesn't know it.
Click to expand...
thats exact same point I made in very beginning of thread,thanks for mentioning this...

If top is peeling,chances are bottom is also compromised.

I see solution being rip it apart and start over...I think OP's ego wont let him do that.
 
#57 ·
jomama said:
I've had culture stones hit me before, but never NTV. Ouch. Honestly, I have a hard time believing that some of the scratchcoat is only peeling where he hasn't laid stone yet. Not trying to call the OP a liar, but the scratchcoat may be weak on the lower stone already laid & he just doesn't know it.
Click to expand...
You are almost certainly correct.

Edit, NTV????
 
Discussion starter · #59 ·
Well the information I have gathered from here and elsewhere has certainly confused me. I was sure there would be one right answer to my question as to what I had done wrong.

Called the manufacturer with my question today and they said it could be done either way. They were unsure why the scratch coat did not take.

I scraped off all the scratch coat above where I have already laid stones. Really had to scrape to get some to separate and some just popped off.

The stones that are already laid seemed to be stuck well to the wall. I can pull on them with my weight and they do not budge. I suppose I could pry them off but I am thinking they seem fine. It is almost as if there is a line at 6 feet where this scratch coat did not bond to the cement board. Wondering if at that height the temperature was elevated and less moisture in the air did not allow it time to bond- besides not dampening the board before applying?
I have enough lathe to put over the 2'x6' bare cement board that is left now. I was thinking just for added insurance I will put up the lathe and scratch coat that and start over from that point.
Any opinions?
I thank everyone that has replied to my initial question. It has been a great learning experience.
 
41 - 60 of 86 Posts
About this Discussion
85 Replies
15 Participants
Last post:
CanCritter
Contractor Talk - Professional Construction and Remodeling Forum
posts
3.6M
members
169K
Since
2003
A forum community dedicated to professional construction and remodeling contractors. Come join the discussion about the industry, trades, safety, projects, finishing, tools, machinery, styles, scales, reviews, accessories, classifieds, and more!
Full Forum Listing
Explore Our Forums
General Discussion Tools & Equipment Business Painting & Finish Work Decks & Fencing