tieing false-wall bumpout to existing finsihed wall...part of a stove install

[fishboat]

I plan on building a six-foot wide 2x4 (perhaps 2x6) false wall around the burner(Bis Tradition CE) & up to the vaulted ceiling. On one side of the hearth the ceiling is about 11 feet up. On the other side the ceiling is 14 feet up. I'll be tiling (sort of) the bumpout with 4 x 16 inch blocks of dry-stacked slate that’s about 1-1.5 inches thick. When all the tile is in place I’ll have around 1000 pounds of “rock” hanging on the bumpout. The Tile Shop says thinset to a suitable backerboard is all that's needed to hold the material up.

While I’ve built many things over the years I haven’t done anything like this. Does anyone have a suggestion on the best way to tie the false wall to the existing, drywalled, finished wall above the mantle? The existing wall is a 2x4 load bearing wall between the great room & the garage. This wall is finsihed with drywall on both sides (I assume there is a vapor barrier in place already). The false wall will just be a bump-out added onto the existing wall.

I'm thinking a grid will be needed as the horizontal portions will be used to tie into the existing studs. Without horizontal sections I'm left with tieing vertical stud-edges of the new wall to veritcal stud edges of the existing wall...doesn't sound good as a toenailed butt joint can't be very strong.

 

[Corey]

Well, I'm no licensed carpenter, but dealing with something similar in my basement...

I would find out what the stud spacing in your existing wall is and where exactly they are located, then build the stud spacing in the new wall at a slight offset to that. Then nail 2x4 straps horizontally to the back of your new wall every 16" or so. Set your new wall in place against the old. Then nail through the straps to the old studs. Because the new studs are offset from the old (even 2" will do) you can face nail right through the straps to the old studs.

What i wound up with was an old wall that had an 8" stud space on the left side, then the normal 16" spacing after that, so I just built a mirror image wall with 8" spacing on the right and 16" spacing. Still had the same # of studs, etc but that gave a nice offset.

Also, If I understand your thin set question, the total weight is somewhat irrelivent as the thinset on each stone supports it so it's not like the bottom stone feels the weight of the stones on top of it. At least not once the mortar sets.

 

[nshif]

Are you doing this only to tile or to reduce CTC?

 

[fishboat]

NS,
This is just to mount the tile. This is a zero-clearance wood stove (fireplace) install.

cozy,
By straps are you referring to the galvanized hanger-type straps sold at HD, Menards...etc? If so, I din't think of those, but they might work OK.

 

[nshif]

If its just for the tile glue and screw 1/4' duroc to the drywall and existing studs and hang your rock. no need for any futher wall. Make sure the existing drywall is attached well maybe add a few screws and you should be fine. Glue the duroc (cement board to the drywall with the same thinset you use for the tile or rock

 

[Corey]

No - by straps, I was referring to 2x4's laid flat and horizontal across your new wall. I guess you might be able to use metal straps if the overall thickness was an issue. In that case, you might want to build the new wall studs only slightly offset from the old wall studs, then screw the metal plates to the back of your new wall, set it in place, then screw from the front to your old wall.

 

[fishboat]

ns,
The existing chase for the existing fireplace is only 21.5 inches deep. The TradCE is 25 inches deep. This leaves the face of the new burner 3.5 inches out from the existing wall. This is where the bump-out false wall comes in...not only would it look better than a flush-to-existing-wall rack face, but it's the only way to give the install a finished look.

cozy,
OK...the horizontal straps as you describe them is what I had in mind. I was thinking of cutting dados in the back of the vertical new stud wall and then attaching the straps. This would make a grid basically & would leave plenty of opportunity to attach to the existing stud wall...as long as the offset is there.