Installing A Marble Fireplace - Brackets vs Adhesive

[EViS]

I want to install a new marble fireplace (surround, back panel and hearth) to replace our old fireplace. The gas connection will be done by a Gas Safe engineer. The old surround has been ripped out and the wall has just been plastered (hardwall and multifinish).

a) What is the most common way of installing such surrounds? Brackets or adhesive?

If adhesive, will a tiling adhesive made for stone be adequate? And if brackets, how are these to be fixed to the back panel and surround?

b) And in order to fix the mantel to the surround, should silicone be used or tiling adhesive?

 

[clubb699]

Installed our fireplace 3 weeks ago me being me i used a bracket, the bolts are 2 and half inches into the wall its going no where

We have little toddlers i would not forgive myself if that marble fireplace tipped over from the glue failing for instance.

For the top mantle we did use good quality no nails that was recommended by the fireplace shop with the downward force and the inner lip marble to secure it plus the weight im happy with that also not moving anywere

 

[EViS]

How did you fix the brackets to the fireplace surround? Was it also marble?

 

[clubb699]

The brackets looked cemented onto the marble not sure what they used tbh

Just googled and this came up

Brackets are bonded to the marble using a special resin adhesive

for what it is god knows i thought it was like a cement

 

[SimonH2]

Just done one at my mates house.

It came with a couple of bits of perforated strip cemented into the fireplace which wouldn't fix it rigidly. I've used those as "stop it falling over" backups, but just stuck the fireplace in place with a line of "sticky stuff" up both edges.

As of today when I asked, he hadn't taken the clamp off that's holding it till the sticky stuff sets (24 hr according to the instructions) - but I'm confident it's going nowhere

The hearth was laid on a bed of plain sand/cement mortar and left to set. So when it was time to fit the back panel and surround, they had a firm base to sit on.
Applied four dollops of sticky to the back panel and temporarily held that in place with a clamp. Then applied a line of sticky to the edges of the surround that touch the wall, offered it up, and pulled it in with a clamp*. I originally positioned the back panel to be a bit proud, so it's pulled back with the surround and ends up without gaps.

* I'd been wondering how to clamp it all, then I had a lightbulb moment. I made a loop with some perforated strapping, and fixed it to the back of the recess with a screw. I then put a normal clamp (one of those "slide along a bar" types) into the loop, and used it to clamp a length of wood back. The wood straddles the surround, so the clamp is holding it all tight against the wall.

 

[EViS]

What 'sticky stuff' did you use? Grip fill or a 'no more nails' type of adhesive?

Also, this fireplace has a rebate of 80mm, meaning that the back panel will need to be fixed some 60mm from the rear wall. Can I simply pad this gap out with 5 or so layers of standard plasterboard, each one gripfilled to the other? Or would I need to use the fire rated plasterboard (red?), or is there a better way?

 

[SimonH2]

What 'sticky stuff' did you use? Grip fill or a 'no more nails' type of adhesive?

Yes, it was something like that. Don't recall the name of it, but it was quite pungent ! I'll be able to "test" it's stick on Saturday when I'm next there.

Also, this fireplace has a rebate of 80mm, meaning that the back panel will need to be fixed some 60mm from the rear wall. Can I simply pad this gap out with 5 or so layers of standard plasterboard, each one gripfilled to the other? Or would I need to use the fire rated plasterboard (red?), or is there a better way?

Dunno.
In part it might depend on how hot it might get. I'd imagine it shouldn't get all that hot, and standard plasterboard is itself fire retardant anyway (but it achieves that by decomposing which releases water).

EDIT: Can't see plasterboard being a problem - otherwise sticking these things to a plaster wall would be a problem.