Mahwah does not smile kindly upon homeowners doing their own work. Lots of high priced permits and inspections are required.
Every time my daughter hired a contractor it was a big mess, and half the time she got ripped off by them. The best work done on her house (which had had some very poor work done on it by the previous owner that the town overlooked) was done by my husband in the dark of night behind closed doors. More than once my husband had to repair shoddy work that a high priced contractor had done.
There seem to be 3 kinds of houses in Mahwah -- really old ones like the one described in this article, subdivisions built in the 1960s, and enormous homes that have been put in in the last 10 years on "tear down" sites.
I suspect there is no shortage of people looking for a 'teardown site' at bargain prices, either. Maybe even some relatives of the folks who did the shoddy and incomplete work, or the ones complaining or levying fines...