Granite bench top

[marineman]

I recently was able to get hold of (at a very reasonable price) a 2nd hand Granite bench top approx 25mm thick measuring approx 2.7m X 5m. still looks pretty good. I'm intending to use it as the top of my servery outside the kitchen window.

I would appreciate advice on the best way of mounting it. Apart from a slot (120X50mm) towards the back edge there are no holes in it. There are marks of what appears to be silicone on the underside.

At this stage I don't see that I have much choice than to glue it with silicone / sicaflex or the like.

I am intending to build a timber / Gal steel frame to which I will cover, mount shelves and doors etc, with the granite on top. Should I fit fibre cement sheet under the Granite or just glue to the frame. Some of the bench will be exposed to the weather, and up here that means wet.

Any advice for installing Granite would be welcome

Part of the front edge is rounded and the other part is still square edged. I know this is a tall ask, but does anybody know if there is a way I can profile the rest of the edge myself so it is rounded?? Or do I have to have professionally "machined".

I've been known to be pretty handy with a Grinder and thought of taking most of the edge off then using some form of router with a grinding bit to finnish off the radius. any thoughts. I don't want to stuff it up but would like to "have a go" if possible.

[echnidna]

I would use liquid nails etc to fix it down.
I think you could cleanup the edges with a belt sander with an aluminium oxide belt.
But why not ask the advice of a local monumental mason.

[Scooterscum]

The granite guys usually use a 2pac glue to glue the tops down onto substrate, but I've used clear glazing silicon to glue down granite at my place no problems.
Make sure you use a substrate underneath. The granite must be supported underneath or it will crack. I've seen this happen even with as little as 300mm between centres frame work under it. Generally 15mm ply makes a good substrate.
Hope this helps
Regards Simon

[marineman]

Cheers Bob & Simon

My plan now is to make a chasis of 25 x25 rhs and fix 15 marine ply to it, then lay the granite top.
I'm going to do the radius the edge later. I'm going to take your advise and ask some profeesionals?

Regards
John

[johnc]

Granite is one of your toughest stones unlike marble which can be easily worked and polished you will find granite tough going, You would find it is probably cheaper to get a mason to round and polish your top for you than stuff around with the polishing paste, diamond blades, polishing wheels and other bits and pieces needed. As mentioned you need a flat base fully supporting the top, silcone is fine as all it needs do is allow movement. Granite expands and contracts like everything else as the temperature changes and you need to allow for this. MDF, cement sheet anything you like just make sure it cannot bow. Granite will sag ever so slightly if your base is poor and then one day a crack will magically appear without warning. Plenty of silicone for the bed and let gravity do the rest, its not very complicated.

Goodluck, JohnC

[marineman]

Thanks JohnC

I figured that there would be alot work to ensuring correct installation. It would probably explain why I have heard stories of kitchen granite tops costing arround $1,000 / m2.

As I wont be able to fit the top until Mid Jan is it alright to store the slab on it's side sitting on some timber Dunnage?

Regards

John

[johnc]

John,


Storing on edge is the correct way to rack your granite, being thin it is prone to snap easily, I would suggest two pieces of pine packing one at each end. Never one in the middle that's the best way to guarantee a break, when you tilt the stone back against the wall a thin block or wedge placed (not tapped) in the gap between the pine packing and exposed gap minimizes the chance of the slab slipping forward. Your packers need only be about one inch thick or less, just enough room for fingers, and pine unlike hardwood is less likely to damage your polished edges. They only need to come into contact with about 50mm to 75mm of granite so just face them out from the wall If you ring around the shops that prepare and sell stone bench tops you will find the cost of a half round is not that dear by the metre, your looking for those that import the polished 1" slabs and then cut and edge to order. The $1000.00 per square metre is probably from a cabinet maker or similar, the last bench we put in was around $175.00 per sqm and it was not the cheapest on the rack either. A quick look under stone masons in the yellow pages should get you the info you need, most monumental masons do not carry the equipment required for the edge you require.
Goodluck, JohnC