Plumbers installed an outdoor faucet in a requested location by drilling through a block basement wall and installing a hose bib that will not freeze. I asked if a turn-off valve needed to be installed on the inside and they said that wasn't necessary since turning the faucet off outside would shut a valve that is 6" inside the house. I think I understand the basics of these frost-free valves and accepted their suggestion. I also asked if they would seal off the hole somehow, and they said they would apply silicon around the faucet.
They left and I believe they consider the job complete. (An invoice will come in the mail, so I haven't paid for this yet.) I'm surprised to see a large opening into the block, and I wonder if the frost-free faucet will be effective even though there's this gap and the basement is unheated. It is not super cold where I am but does get in the low 20s (F) and one or two months have a daily mean temperature around freezing.
Does this need a turn-off valve further in the basement? It makes sense to me that it does not. The end of this frost-free faucet is pretty close to where a turn-off valve would go anyway. For context, this is a relatively small house and I don't see any sections of the house's plumbing having shut-off valves, but there are shut-off valves just before every plumbing fixture except this one.
How should this opening in the block be sealed or insulated? Given the importance of the faucet's interior end not freezing and the fact the basement is unheated, I expect this hole needs to be filled in somehow.