Q: How do you determine the depth of the deck footings to assure you have gone below the frost line? I live in central New Jersey, and thought I've always heard that the frost line here was 18 inches. But from reading a few articles on decks, I've seen conflicting information. Do you have a reliable resource? --Frank G.
A: As you can imagine, frost lines vary widely by region. Also, most codes require that your footings be an additional 12 inches below the frost-line depth, as an added precaution against rare deep-freezing conditions. So, your best bet is to simply call your local building department and ask.