Daniel Prince wrote:
DerbyDad03 wrote:

Was does frost have to do with having a basement or not?

My understanding is that in areas that have frost, footings have to
go four feet or more underground.

To be more precise, footings have to be placed below the frost line. In
many areas, it is indeed 4 feet. In some areas it's less, in some it's much
more.

https://www.decks.com/deckbuilding/D...rost_Depth_Map

Builders often decide that if
they have to dig that deep, they might as well dig a little deeper
and have a basement they can use for water heaters, furnaces, oil
tanks, water filters, water softners, electrical panels, pipe,
ductwork and wire runs etc.

To be more precise, the person(s) who contracted the building to be built
will decide whether a basement should be added, assuming that there are no
other factors the would prevent it.

In your OP you said "I live in an frost-free area so I do not have a
basement"

I don't know the real reason as to why you don't have a basement, but it's
not because you live in a frost free area. In other words, there are lots
of houses in frost free areas that have basements for all the reasons you
mentioned above, plus many more.

Good luck with your shelf project.