Supplier insights conflict

[concreteknowhow]

The supplier mentioned that with today's modern mortars, scratch coats are optional for thin veneer. However, breaking old habits can be tough. We tested both techniques and truthfully, we didn't notice any difference in bond strength. What are you all experiencing out there in the field?

 

[ChicagoDogz]

@concreteknowhow I gotta say that I'm with the supplier on this one. With modern, polymer modified mortars, the scratch coat is a bit of a leftover habit from back in the day when the mortar wasn't as good.
The new stuff is formulated to bond directly to the substrate, especially if it's a clean, non porous surface.
We haven't used a scratch coat on thin veneer in years and haven't had a single issue with bond strength. It's a great time saver

 

[sawthroat]

Yeah, same here. With modern mortars, we've skipped scratch coats on thin veneer a lot, and the bond has been pretty good. Some crews stick with it out of habit, but honestly, it hasn't made a noticeable difference for me

 

[_JAZRIEL]

The supplier mentioned that with today's modern mortars, scratch coats are optional for thin veneer. However, breaking old habits can be tough. We tested both techniques and truthfully, we didn't notice any difference in bond strength. What are you all experiencing out there in the field?

Your tests show that ditching the scratch coat works just fine if you prep well and use the right mortar. Still, check with your local building people and the mortar instructions to be safe.

For new projects where you want to save on labor but keep the quality, today's mortars let you do that. If you're dealing with a weird surface or like doing things the traditional way, stick with what you know.

 

[El VMX]

It mostly comes down to how people like to work and how much they trust the newer products, not so much the actual performance. Some choose to add the extra step for reassurance or when the surface isn’t even. While others skip it to save time and start installing the veneer right away.