[muppet29]

Hello

I'm about to undertake a thin brick veneer project (interior). The wall is 24' high (2 storeys), no corners, 560sq feet in total. The wall is currently drywall painted with a semi gloss paint but the wall itself has some texturing. I live in the desert and it's inside (not a bathroom) so i'm not too worried about moisture.

the problem i'm having is that i'm getting dramatically different opinions on the use of Hardie Backer - Several highly knowledgeable people have said i don't need it and that it would only ADD weight to the wall. that i can use a good mastic glue and i'm good to go.

Others have said they don't recommend that but instead i should first use Hardie Backer / cement board.

i'm really at a loss. Those for Hardie Backer say that i need it to hold the brick - others have said it would only add weight to the wall and i should be fine as i'm just building from the ground up.

please help! why so many different opinions and what's the way to go??

 

[Windows on Wash]

I would always prefer to use a thinset when I can. Using duroc or hardie board will allow you to do that.

Fastening to the wall tightly should carry the weight that you add just fine as long as the wall is capable of handling it.

 

[carpdad]

The texturing is a thin veneer of compound and may separate from the backer. I think you'll be more secure by adding a new backer over the old. 16" oc studs are good for drywall but if wider, I'd thicken up the backer. I'd search the manufacturer's manual for mastic or thinset, and the specs on the backer. I am assuming the wall sits on a foundation, but if there are wide windows, doors, garage, etc, I'd make sure the beams can take the additional weight.
If possible, identify and document everything inside that wall.

 

[Tscarborough]

If a "knowledgeable" person advised you to put thin brick over a painted surface, then they must be knowledgeable in some other field. If they told you that you could adhere it to a painted sheetrock surface, then they are really, really wrong.

For a backsplash under counters, there are products that can be used to prime and create a suitable surface for thin brick. For an 8' wall, much less a 24' wall, no, never, just don't.

1/4" hardibacker, screwed to the studs through the drywall, and use polymer modified thinset to attach the brick.

 

[ddawg16]

What is below the wall? In other words, what is the foundation below?

I personally would do some calculations....determine the lbs/sq ft of the stone you're using...then add it up....can the foundation hold it?

As for weight on the wall....all it's really doing is holding everything vertical. The actual weight should be in shear....in other words, each stone sits on the stone below it. The bottom stone has all the weight on it.

With that said.....if you attach directly to the painted surface of the wall, if there is any movement of the stone, it's basically going to peal the paint off the wall in a shearing motion.

So....you would be much better off with hardibacker. It adds more weight, but it gives you a much better surface to adhere to. It will put some weight on the studs...but if done right, most of the weight is transferred down to the bottom.

Which gets us back to the original question....what is below that wall?

 

[Tscarborough]

Dawg, it doesn't matter what the foundation is, or anything like that. Thin brick or stone is an adhered veneer. The weight has to be 15# per square foot or less, as that is a load that a 16" o.c. 2x4 stud wall can support. Thin brick is nowhere near that, including the hardi-backer and the thinset.

In this application, 2 things matter: Adhesion and peel. You can not get adequate adhesion on a painted surface, and if you do manage to, it is possible the entire brick surface will peel the paper from the sheetrock.

Thin brick is expensive, but it is really expensive when you have to do it twice.

 

[Canarywood1]

I'd be worried about the wall being able to take the extra weight, i believe what you have is in effect a shear wall, and the density of the lumber species determines how well the sheathing fasteners will hold.

Add the hard backer and the brick veneer, and it's quite a bit of extra weight.

 

[Tscarborough]

The weight is not a concern, just deflection that could cause peeling. You are adding about 5 pounds per sqft, well within the deflection and shear ratings of a 2x4 stud wall sheathed with 1/2" sheetrock and 1/4" hardie-backer.

 

[ddawg16]

Dawg, it doesn't matter what the foundation is, or anything like that. Thin brick or stone is an adhered veneer. The weight has to be 15# per square foot or less, as that is a load that a 16" o.c. 2x4 stud wall can support. Thin brick is nowhere near that, including the hardi-backer and the thinset.

In this application, 2 things matter: Adhesion and peel. You can not get adequate adhesion on a painted surface, and if you do manage to, it is possible the entire brick surface will peel the paper from the sheetrock.

Thin brick is expensive, but it is really expensive when you have to do it twice.

You are joking....right? a 24' tall wall...with at least 10 lbs sq ft or more for the tiles....that is over 240 lbs per linear ft...not including thin set, backer board, drywall, and any other dead load being applied, and you don't think foundation is a concern?

 

[Tscarborough]

It doesn't really matter what I think, it matters what the codes and the structural engineers think. My bible for adhered veneers is, "Direct Adhered Ceramic Tile, Stone, and thin brick facades", by Richard P. Goldberg, AIA CSI. While it is directed at commercial and exterior work, the principles apply, and interior work performed to exterior levels will always be superior (my recommendations were NOT to the level of exterior work in regards to waterproofing detailing).

Hey, it is the internets, you asked for advice. If you want a consultant that can be arranged.

 

[Tscarborough]

I will give you this example though, because it is a common mistake I see people make when building pizza ovens, for example. They say, "Wow! this thing is going to weight 3000#!, I have to build a platform that is crazy strong". Then they build a platform of 8" CMU, pour the cells with rebar, etc. The reality is that the PSI requirement of an oven is less than 20 PSI of the bearing surface. That does not require an earthquake proof platform.

In your example, lets take the 560 SqFT and call it 20# per square foot, including the drywall, hardi-backer, thinset and brick and mortar. 560x25=11200 pounds. Lets call it 24 foot tall by 23 foot wide. 23 feet x.33 (a 2x4, but it is probably a 2x6)=7.59 square foot of bearing area for the wall. 11200/7.59= a PSF of 1475 or a PSI of 10.247. Negligible compared to a refrigerator for example.

 

[NJ Brickie]

Tscar is correct. The issue here is adhesion. Backer board screwed through the drywall is needed.