# Best Adhesive for Stone Veneer on Exterior Surfaces?



## Canarywood1

JulieMor said:


> I'll be installing cast stone on the outside of my house. The last time I did something like this was about 30 years ago and it was inside around a fireplace. Back then I used standard mortar to adhere the stone to the lath.
> 
> When we were in the store checking out the stone veneer, the sales guy mentioned something about an adhesive that brought to mind a tile adhesive I used recently to set tile. It feels like dry silicone when cured and bonds much better than the mortar type.
> 
> Then he said, "It's weatherproof and will last forever." Or something to that effect.
> 
> So we took home the brochure he gave us and decided to order the stone. In the brochure it details the installation and states using standard mortar to adhere the stone to the lath.
> 
> Did I misunderstand him? Or is there a better product out there now than mortar for adhering the stone to the lath?


 



Probably best to ask the manufacturer if you can use an alternative to mortar.


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## TRUEPRO

You always want to use type S mortar for any exterior stone application (natural or PC). The only time you would use high strength adhesive would be for any indoor use. The adhesive has not been proven (yet) to stand up against the elements. Now, i have installed every kind of real or precast stone imaginable and have never had a problem using mortar. I am not saying that the adhesive would not hold up but IMO it would be a risk. If any of the stones were to "fall off" at any given time, the fix would be quite simple. More adhesive. 

Do a "test" area and see how you it holds up. If your confident in the results, roll with it. Obviously your using a drystack stone so make sure to keep everything as tight as possible to lock all the stones together. 

NEVER LISTEN TO LOWES/HOME DEPOT sales associates. Always check manufacturer specs or consult professional. GL


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## jomama45

The point where you should have know he was full of BS is when he said it would "last forever".....

Nothing wrong with Type S or N mortar, every manufacturer I've ever used has recommended one or the other. If you want to play it extra safe, you could also add a few ounces of bonding agent per batch as well.


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## TRUEPRO

jomama45 said:


> The point where you should have know he was full of BS is when he said it would "last forever"......


And ever and ever and ever...riiight


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## JulieMor

TRUEPRO said:


> You always want to use type S mortar for any exterior stone application (natural or PC).


The instructions from the manufacturer said to use 1 part N type cement with 2 parts masonry sand. I'm an electrician. This is all Greek to me. What's the difference?



TRUEPRO said:


> NEVER LISTEN TO LOWES/HOME DEPOT sales associates.


It was a Menard's sales associate, so I guess he's okay. :whistling2:


Anyway, I drew this up in case I have to get a permit. How does this look? 









The manufacturer claims no structural changes are required, like a brick ledge. I want to bump the columns out on either side of the garage 12". I have a 24" overhang there so that's not a problem. But I'm wondering about the weight. Each column could weigh 1,000 lbs or more. I plan on using 3/8" or 1/2" lag screws into the studs and top plate but will that be enough?


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## Code05

Nice plans. What program did you use?


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## JulieMor

Code05 said:


> Nice plans. What program did you use?


AutoCAD MEP 2008.


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## jomama45

I like the fact that you're "padding" out the stone from the existing wall so much, as long as you have plenty of room to tuck it under the overhangs yet, as well as a adequate way to keep the column from sagging........


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## TRUEPRO

JulieMor said:


> The instructions from the manufacturer said to use 1 part N type cement with 2 parts masonry sand. I'm an electrician. This is all Greek to me. What's the difference?


Hears a little guide to remember mortar strengths, Descending from Strongest to weakest. M a S o N. Not sure if type M is even used anymore but N and S are the two common mortars. S is used for structural masonry and N is used for Veneer. I use the strong stuff for stone even tho N is more commonly used. I like my walls overkilled forever!


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## JulieMor

jomama45 said:


> I like the fact that you're "padding" out the stone from the existing wall so much, as long as you have plenty of room to tuck it under the overhangs yet, as well as a adequate way to keep the column from sagging........


I've got the room under the overhang. Even with the 12" bump out, I'll have 12" left. The sagging should be resolved with the 1/2" plywood. My biggest concern is hanging it on the existing structure. 




TRUEPRO said:


> Hears a little guide to remember mortar strengths, Descending from Strongest to weakest. M a S o N. Not sure if type M is even used anymore but N and S are the two common mortars. S is used for structural masonry and N is used for Veneer. I use the strong stuff for stone even tho N is more commonly used. I like my walls overkilled forever!


Now I know. Thanks! I like the overkill factor too. I think I'll go with the S. Is it any harder to work with?


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## TRUEPRO

No its pretty much the same. And don't use 2-1 to mix it either more like 2.6-1. You don't want it too "sticky". Then it can become a little difficult to work with. Gl


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## jomama45

TRUEPRO said:


> Hears a little guide to remember mortar strengths, Descending from Strongest to weakest. M a S o N. *Not sure if type M is even used anymore *but N and S are the two common mortars. S is used for structural masonry and N is used for Veneer. I use the strong stuff for stone even tho N is more commonly used. I like my walls overkilled forever!


Type M is still typically used for below grade work, such as crawlspace & frost wall foundations, full basement's, etc.......


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## jomama45

JulieMor said:


> I've got the room under the overhang. Even with the 12" bump out, I'll have 12" left. The sagging should be resolved with the 1/2" plywood. My biggest concern is hanging it on the existing structure.


Not sure how I missed the info you gave under the post with the drawings........

What about replacing all of those 2x4's with 2x10's and either toe-screwing them in, or screw an additional 2x4 to the side of each for fastening them to the existing studs??


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## TRUEPRO

I live in coastal virginia so 99 percent of my work is right at sea level so i never work below ground for anything. Cant say iv ever even mixed a bag of M.


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## JulieMor

jomama45 said:


> What about replacing all of those 2x4's with 2x10's and either toe-screwing them in, or screw an additional 2x4 to the side of each for fastening them to the existing studs??


The problem with that is the 2x10 cupping over time, unless I got a very straight one with no heartwood. I'd probably have to back it up with a 2x4 every 2' or so.

I'll use screws and glue for the plywood on the side. That should take care of any sagging. I'll have to devise some way of securing it to the existing wall. Maybe I'll tear off the existing siding there and tie the bump out to the existing studs and plates. If that fails it will be because the wall came down.

Thank you to all who replied. You've saved me from a lot of headaches.


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## Tommyboyrn

Okay I know this was old thread but I need help......
I have outdoor cooking area I have framed and used 5/8ths permabase into metal studs (they were free so why I used them). I was reading where to add acrylic additive to mortar to cover corners etc....
I bought 2 gallons keralast and 2 bags of Type S mortar.....went to mixing and almost immediately realized something was not quite right. Set up fast.
So I made quick work and toward end guy at building supply said I could add some water if needed....so i added little at end.
I didnt add sand (didnt know if I needed to).....temps outside 50 down to 40 up to 60 today.
Go out today and its cracked.....so my question....hammer it off redo? Let dry some more? 
Im a DIYr who is not stupid just want overkill to hold veneer manufactured stone eventually...the corner on the 45 to the face of the cooking area was reinforced with metal lathe over the permabase


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