Drilling Stone for Fireplace Mantle

[CurlyDave]

Yep its veneer, just a surface decoration not a structural component. So Practice drilling on an outside rock to see what it does if it splits then you need to go through the mortar.
With my mantle the uprights (mine are cast concrete that match our stone the local brickyard had them) really dont hold its the lag bolts that go into the studs that do all the holding.

If the rock inside is a veneer, and the rocks outside are not thin, flat rocks, they are not from the same source as the veneer. How they behave is not going to give any real information on the veneer rocks.

That electric box can be very helpful. Turn the power off and look inside with a flashlight. The odds are quite high that there is a stud located at one side of the box. Other studs should be on 16" centers.

Get the very best stud sensor you can find and look for them. The rock may make this difficult, but a very good sensor may find them.

 

[sparc]

i was thinking that he might find that there was block behind that veneer, not wood framing.
but either way I think killing the power and peeking alongside or even remove the box for a
look see is an easy way to know for sure what's back there.

 

[SPIKER]

Looks really nice but like a few others mentioned it appears to be veneered in the photos. The stone may be REAL (non-cultured) but the consistent semi flat surface makes me think it has to be some sort of veneered or cultured stone product. If you have large hunks laying around then perhaps someone with some REAL skill did indeed cut it from local sources of rock.

In any case I would look for one of the outside chunks and experiment on that for a while with different drilling/core sawing and bonding techniques.

Also good catch on looking inside wall outlets in that stone wall area to find out what is in behind and or if it is wood and or the thickness of the stone veneer/structural stone.



Mark

 

[forgeblast]

The stone wall doesn't go through to the outside of house. The outside is brick. Does that make this a veneer? The stones are very real and very large/heavy. There scattered stones in the yard that I'm sure were just leftovers.

All the stone work I did on my house is natural or real. I would go to the creek when it was dry and pick up the flattest stones that were about 1/2 or less thick and put them on our house. When I say veneer I am meaning not structural; but meaning its on the surface, not veneer as in a "cultured" stone. We have mostly sandstone, and finer mudstone. We are in Bluestone area (have according to a geologist a great spot for a quarry at the back of our property) so a lot of my stone had those nice hues.
What he will probably find is some lathe behind the stone. Thats why I am recommending drilling a small hole through the easily fixed mortar and not trying to drill through the stone. I have cracked stones just carrying them, so I would avoid drilling them otherwise you may end up with a more difficult job.

our mantle install was different, i had knotty pine there, then we put in backer board after we hung the mantle, and then put the stone on.

all that stone is over block, that had the stucco cleaned up and then mortared in place. Its all natural just a veneer.

is all structural.

 

[EddieWalker]

Why drill through the rock on the mantle? I would outline the finished size of the wood and cut out the stone so you have a solid back to attach it to. A 4 inch grinder with a diamond blade will slice right through whatever is up there and you just chisel it out.

I would be sure to get to the studs in the wall and attach a plate directly to the studs. Depending on the size and weight of the wood mantle, I think metal would probably be what I'd use for the plate.

There are some brackets designed for this that you attach to the wall and the back of what you are hanging with a hook and hole type of design. The ones I've seen have a squarish hook that is wedged so it gets tighter as it goes into the hole. It's been years since I've seen this, so it might take awhile to find something like it online.

Eddie

 

[Maknwine]

Tks everyone for taking interest in the thread... All good advice and appreciated.

Took off the outlet plate and did not see a 2x4 anywhere. All around the box is about 2.5-3 inches of mortar.

I'm still planning on using legs out to the sides for primary weight support.


Eddie, are you saying take a 3"x 7.5' area out of the rock wall for the redoak piece to slip into? If so, I hadn't thought about that at all. Seems like that would take a heck of a lot of grinding.

 

[EddieWalker]

A diamond blade on a grinder will cut though rock, brick and cultures stone real quick and easy. Then you either hit the rock with a chisel and hammer, or use a SDS hammer drill with a flat chipping blade. It's dusty, but that's easy to control with plastic and tape. From the time you turn on the grinder, it should take an hour to cut. Maybe another hour or so to get rid of the stone. I'm thinking it's a pretty simple job.

Eddie

 

[Shaddoh]

That stone fireplace is beautiful! I had a similar idea after the "big freeze" a few years ago lol. Who did you use for the installation? We used Southwest Brick and Fireplace | Expert Service in Dallas Fort Worth absolutely amazing company everything from selecting stone to installing it 100% great experience.