Attaching Thin Stone Veneer to Plaster Walls

[jeffesonm]

I'm finishing off a wood stove install and would like to build an alcove next to the fireplace in which I can store wood. I removed some cabinets that were previously there... you can see the glue residue and old blue paint to the right of the fireplace.

I ordered matching natural thin stone veneer and now I need to figure out the best way to attach it to the wall. The house was built in 1957 and as best I can tell, the walls are sheetrock covered with metal lathe and then plaster on top. Here are two pics of the walls... the first is inside a closet where a piece of trim is missing so you can see the exposed edge. The second is a small area I chipped away adjacent to the fireplace where I intend to install the stone.

I've read all over the place and it sounds like there are two generally accepted methods for interior install... first is to screw wire lathe to the wall, scratch coat with mortar and then mortar stones to wall. The other is to use thinset to attach stones directly to hardi backer. Both of these methods are approved by the manufacturer of the stone.

I haven't been able to find any recommendations on how to attach stone veneer to a plaster wall. I could remove the plaster, put up hardibacker and do thinset, but that would be messy and time consuming. I could do the metal lathe/mortar but then the wall would consist of sheetrock, lathe, plaster, lathe, mortar, stone, which seems like a lot.

Any other options or input?

 

[semipro]

I'd suggest going with the Hardie backer over what's already there using whatever adhesive Hardie recommends between wall and backerboard. I'd also make sure to attach the backer board to the studs with the screws made for backer board.

 

[ironpony]

lath and mortar bed is the only accepted practice I know of, please make sure Hardi backer or Duroc are manufacurer approved. It would be very disappoinitng to do all that work and have it fail
thinset generally will not support the weight of the stone till it sets.

 

[ScotO]

Ironpony nailed it, IMO. I did a TON of natural stone veneer both inside and outside of my house. Here's what I would do in your situation.....

Get some metal lath and some 3" to 3 1/2" screws (get good ones), and small washers. Make sure your screws are long enough to get through all the substrate and into the studs to support the weight of the stone. Put a washer on the screw and screw the mesh on every stud at every 6" to 8". Overlap your mesh by three inches at any junction where the mesh comes together. Put a scratchcoat of type "S" mortar over the mesh, directly on the existing substrate (given it is plaster or cement board). Use a scarifier tool (looks like a handheld rake) to scratch the still-wet mortar, and let it dry a minimum of 24 to 36 hours. Then when the scratchcoat is dry, you install the stones. Back-butter the stones with the same type "S"mortar mortar. Mist the wall with a spray bottle of water prior to setting each stone. You want the wall slightly damp so it doesn't suck the moisture out of your back-buttered stone. I always install my stone from the top-down. This way you don't get slop all over your hard earned work. But that's a personal decision.

I use a 3 to 1 mix when I make my mortar (3 parts sand to 1 part type "S" mortar ). Mix it to the consistency of mashed potatoes, or just slightly wetter. Take your time, post some pics. Before you know it, you'll be a regular pro....

 

[jeffesonm]

Thanks for the feedback all... I think I will go with the lath and that seems to be the preferred approach.

The end of run will be in between two studs... should I just screw the lath into the plaster along the edge?

 

[ScotO]

Thanks for the feedback all... I think I will go with the lath and that seems to be the preferred approach.

The end of run will be in between two studs... should I just screw the lath into the plaster along the edge?

You may want to consider doing butterfly anchor nuts/bolts on the end of that run. maybe install one every 8" or so......

Or you could try these.

Whichever route you go, make sure you install them properly and there is NO NEED TO OVERTIGHTEN them. Your goal is for the stuff to NOT pull away from the wall.