Do any of the pro's have an idea what the frost line depth is for south- central new jersey?? The town is trying to tell me it's between 36 and 42" but that sounds kind of deep for an area that rarely gets winter temperatures below freezing for long perods of time.
According to the Corps of Engineers, the 3' depth line runs east-west through the middle of New Jersey. More for the north half.
Code frost figures are based on the coldest weather (greatest penetration) over a long period of time since it only takes one cold year in the life of a structure to cause severe damage. It could happen any year, not just the past 30 or 40 years). Lack of snow cover and traffic can increase frost penetration.