Granite Benchtops Information Required
The background:
We're in the process of installing a new kitchen. The cabinets are standard water resistant particle board. The flooring will be ceramic tiles layed on James Hardie ceramic tile underlay on top of yellowtongue over timber joists. The kitchen is a U shape, approximately 3m across the back by 2.5m on each side. There will be two cutouts for the sink and cooktop in the benchtop, each in the 800-900mm width range. The benchtop that we are considering is "Uba Tuba" granite.
A few questions about the granite benchtops we want to install:
1) How are the cutouts in the benchtop normally managed? It occurs to me that the two approaches would be to either cut a single hole in the center of a single large slab, or to simply cut a slab in half, as it were, and then match appropriately sized granite spacers front and back of the newly formed hole. The second method would obviously result in visible seams at the corners of the cutout, but the reason I bring it up is:
2) One of the stonecutters I've spoken to about the job refuses to give me a quote for 20mm benchtops. His claim is that 20mm granite is dangerously prone to cracking at the corners of cutouts (especially on a kitchen layed on a timber flooring substrate, as opposed to a concrete slab) and that he will only quote on 30mm or 40mm stone. Nobody else has given me this warning. The reason I'm particularly suspicious of the advice is that the suggestion that 40mm top might alleviate the problem, given that a 40mm top is simply a 20mm surface with an extra 20mm edging strip across the front, I can't see how this would help. The question is then, Is this a genuine warning, or is this guy simply trying to charge me extra by pushing me to get thicker stone than I actually want?
The two questions are related, because it strikes me that if a cutout is manufactured such that there are cut joins at the corners of the cutout, then it is these that might potentially fail, a much simpler fix down the line than having to replace a slab that has a genuine crack which has propagated from the weak point at the corner of a cutout hole.
3) In addition, we want a raised granite servery on one side of the kitchen that will be approximately 300mm wide atop a 1150mm high, 110mm wide stud wall. The overhang will be mainly on one side, with only about 20mm overhang on the other side. Is 20mm granite sufficiently robust to handle this design alone, or should the design include some extra surface beneath the proposed granite top? If so, what sort of design should I be looking at?
All suggestions, observations and advice appreciated.
Cheers,
Steven.