Need Opening on Granite Counter Cut Larger for New Cooktop

3 pros!
Question by Bittybee8: I need to replace my glass cooktop that broke. All the new cooktop models available (even the 30" size that my old cooktop supposedly is) require the rough opening in the countertop to be about 1/2" to 1" larger on each side than the existing hole in my granite counter. There's enough room to cut it larger within the cabinets, but can it be cut in place? How much is this going to cost me? Thanks!
Answered by LCD: Yes it can be done in-place - by some contractors. One caveat - make SURE the work order you sign includes rounded corners in the cutout - not just taking a diamond blade in a skil saw and slabbing off the unwanted material, leaving sharp corners - that is quick and dirty but leads to cracking, especially at sinks and countertop stoves where the remaining amount of material front and back is narrow. The ENTIRE cut surface should also be chamfered or rounded (usually with a router but can be ground) to eliminate the sharp edges on the top and bottom of the cut, which (especially on thinner countertops) can serve as a crack initiator. Extra cost for that probably about $50-100, but considering it protects your entire countertop against cracking, well worth it.
Below are links to some prior similar questions with answers that should help - you may go through quite a number of countertop installers before you find one that will do it in-place though (even though that is almost certain to be cheaper in this case), because cutting a larger opening in a stone countertop can be iffy because you are at a weak place anyway - going wider is less dangerous than nibbling away at front and back. If that is what is needed, may take some intricate hand removal of cabinet material to provide underspace to full-contact epoxy glue reinforcing on the underside of the front and back thin sections. Of course, you eventually reach a point where the front and back portions are too narrow and no contractor in his right mind will do the cuts - typically manufacturers/installers prefer 4 inches or more, around 3 to 3-1/2 inches is where it starts getting real scary, though I have seen a front lip as narrow as 2 inches with thick countertop and full reinforcement underneath.
Countertops is the Search the List category for this type of work - and I would expect probably in the $400-800 range if normal thickness granite (1" or less) depending on back clearance for the saw (wall or backsplash to cut line clearance) - maybe 50% more or so if 1-1/4 to 3 inch thick because the wear and tear on the diamond cutting tools is fierce on thick countertops.
Obviously not all the following directly address your situation, but I chose ones that address the issues of enlarging an opening or modifying a countertop in-place, so I tyhink there are at least parts in each one which should help you.
https://answers.angieslist.com/Can-existing-granite-countertop-sink-open...
https://answers.angieslist.com/Can-I-cut-5-granite-counter-fit-larger-re...
https://answers.angieslist.com/I-contractor-cut-modify-granite-counter-s...
Answered by LCD: Sorry - don't know why but the AL system ran the font different at the end, and put a "/" between the links - but the individual links still work, just click at the http: for each one.
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