Here is an example of why hiring a professional is important. Take a close look at the picture. That's granite dust all over a customer's kitchen. The customer had a old white under mount sink that had fallen loose. Rather than just fixing the existing sink they opted to replace it. They hired the guy pictured here to swap the sinks.
He measured then went out and bought a new sink. Well he measured the hole wrong and rather than getting a different sink that fit he opted to pull the old sink and cut a new sink hole. Shouldn't be a problem I do this from time to time. The difference is I mask the work space by building a enclosure to ensure dust containment as much as possible.
According to the home owner this guy spent over 36 total working hours trying to swap the sink. And when he was done the new sink still didn't fit in the hole correctly the front edge is crooked and the entire sink, for some reason, is elevated 1/8th off the surface of the counter. That gap is filled in with black acrylic caulking. It's not easy to free hand cut granite in place but I looked under the sink the new cut edge had a noticiable wave amplitude. There were points were the cut edge met the inside of the cabinet frame and other spots along that same edge where it was an 1" off the frame.
The dust fried all their appliances, they had to have all the carpets and drapes professionally cleaned and their ducts cleaned. They have spent so far 6k repairng the damage done to their house and the best news is they guy lied about having an insurance policy. He presented himself as a Restoration business and assured them he carried insurance but it turns out he was carrying no liability insurance.
He was doing these restoration work part time to supplement his income when he wasn't working his full time job. And their home owners insurance company denied the claim because of an exclusion for poor workmanship from a hired contractor.
The dust was so invasive that after the homeowner cleaned the microwave it started sparking inside from residual airborn dust the first time she tried to use it. He also scratched the new sink in 2 places and broke the vertical cabinet frame post between the doors below the sink. Damage he never told them about and tried to repair with an L bracket. Do you care to guess how well he did are reassembling the plumbing beneath the sink?
Bottom line hire a professional.
By Josh 6-2-2017