Photo by e fedorzyn on Unsplash
Here in Chicago, many of our older homes were built with a vertical mail slot with an interior access door. This is especially true for our brick Bungalows and English Tudor style homes. Unfortunately, many mail slots have become rather nonfunctional as they are typically too small for today's mail. And many of them have either lost their door flap or hinge pins. I cannot tell you how many inquiries we receive asking if we have replacements! Trouble is, there were so many different sizes and many were made specifically for the home or builder at that time. Most are cast brass.
There are options:
If your vertical mail slot is intact, you can simply purchase and install a new mailbox and secure the door flap shut.
Or you can have the mail slot removed and brick in (or stucco over) the cavity left from removal. You would still have the interior access door as a historic remnant. A new mailbox can then be placed over the same location or installed in an even better location. My neighbor just had this done by his tuck pointer (mason) and it looks great.
What I did with my own Tudor style home is pull out the old mail slot, stuffed the cavity with insulation, covered the cavity with a copper sheet using silicone. And I had a custom over-sized, copper doorbell made by one of our Craftsman. It is a rose design (and available on our website). The old doorbell was right below the mail slot so the wiring was there. We then installed a new mailbox right next to it that can accommodate mail, magazines, and such. As for the old interior mail slot access door, I just keep the dog walking apparatus in there. Sweet!