Granite floating shelf advice

[Dustyy]

Hi, wondering if someone could offer some advice on whether this can/should be done or if there is a better way of achieving the result.

I am currently in the process of knocking out my lounge fireplace in readiness for a wood burning stove (house is a 1930s semi - original opening partially bricked up for gas fire installation).
The original arch is at approx 1400mm from floor level and looks abit unsteady so I intend to put in a lintel at approx 1200mm which will be the top of the new opening. We have a nice piece of granite which would make an attractive floating shelf above the fireplace but I am unsure on the best way of fixing it.
The shelf dimensions are 1500mm x 210 x 25mm and it weighs 24kgs.
As I was putting in a lintel anyway and bricks will need to be removed, I was considering partially sinking the shelf into the wall, say to a depth of 60mm and then cutting bricks and mortaring around the shelf. My concern was though if this option is viable would this be enough to prevent the shelf being pulled out accidentally or was there somesort of fixing/resin I could use to "secure" the shelf in place.
I had thought about drilling into the granite to put some sort of dowel in to help secure it but am worried about the granite cracking/splitting when drilling.
Can anyone offer any advice as to the best way to secure the shelf or does it sound too heavy at 24kgs?
Thanks in advance.

Dustyy

 

[freddiemercurystwin]

A client of mine wanted to do this, tbh I didn't pay too much attention as to whether he actually did it or what it turned out like as it wasn't within my remit to do, I just did it as a favour so I sketched a bracket for him to take to a steel fabricator to knock up. You would need to get the corresponding holes drilled into the depth of your shelf by a stone mason or similar and then resin the thing to the wall. Well you get the gist.

Untitled

• freddiemercurystwin
• 2 May 2014
• 1

I guess you could cantilever it out of the wall though I would have looked for it sitting a full brick depth into the wall though that will compromise the depth a bit.

 

[ban-all-sheds]

You should find useful ideas from this, and links to companies who make brackets.

http://images.google.com/images?q=floating+granite+shelf

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[Newboy]

If you do go down the floating shelf route it will need more than just end and back edge support i.e. bracket as FMTs post.

Unsupported along it's length it will be very easy to fracture - as anybody who has fitted granite worktops!

Very good in compression but low shear strength

 

[Dustyy]

Thanks for your replies so far.
So Newboy are you suggesting that "embedding" the granite along one long edge to say 100mm of the 210mm depth would not be a good idea as it could "snap off" if leant on heavily?
Whilst on the subject of granite, regs state that I need 300mm from the front of the stove to the nearest combustible material, which would be the carpet. Other than the necessary dimensions to satisfy the regs, would a single piece of granite laid in front of the stove be suitable or are there any other construction regs I need to bear in mind. Looking around for various supply sources it seems that some granite pieces are only suitable for gas or electric appliances but not solid fuel? What would be the reason for this?

Cheers

 

[Newboy]

for the shelf I'm suggesting that the granite needs more than just support on three edges - as earlier post from FMT. I doubt that it will snap/sheer along the supported edges but that the centre/front unsupported section may fracture. It is unbelievably easy to crack a long/thin piece of granite.

The principle for most floating shelves is a concealed bracket supporting the shelf by steel rods concealed within the thickness of the shelf along it's length

I suspect that granite isn't suitable for a solid fuel due to heat levels - may well fracture due to high temps and heat stress but you'd need to ask around - I'm just taking a guess

 

[ban-all-sheds]

for the shelf I'm suggesting that the granite needs more than just support on three edges

UIAM the OP was thinking of supporting it along 1 edge, not 3.

 

[Newboy]

Having re-read the OP I think you're right - for some reason I had a mental image of a shelf in a recess!

In which case:

1) Note to self - read more carefully and don't assume!
2) Note to OP - it won't work without some significant additional support

 

[Deluks]

Too much hassle, use brackets or maybe brick corbelling at each end.

 

[Dustyy]

Thanks for all the replies and advice. Have arranged for a local stonemason to polish up the piece and drill four holes for bolts
and resin fixing to the wall.