Odd rim joist situation
I apologize if this is the wrong venue for this question. I am running into a weird situation with my 1942 house and trying to replace and rebuild a deck. The original deck was a noncompliant horror show that I’m surprised never fell down. I have since torn it down, but am running into issues with rebuilding a safe, code-compliant deck.
The foundation / joist setup for my home is very weird. I have a concrete foundation, and then a 6″x6″ beam that sits on top of the concrete foundation. On top of that 6×6 beam sits the 2×8 floor joists. The floor joists extend completely on top and to the outside edge of the 6×6. There is currently a 1×8 “rim joist” of sorts, which is nailed to the ends of the joists. This 1×8 “rim joist” doesn’t support any load above it and is unsupported from below, since it extends past the foundation wall and what not by its entire 3/4″ thickness.
The previous owner’s solution was to just run about 8 lag screws through the ledger board into the 6×6 beam, for the entire 30′ worth of ledger, yikes.
What are the implications, or any issues with removing the existing 1×8 “rim joist” and attaching a 2×12 in its place, and then attaching a 2×10 treated board to the new rim joist as the deck ledger? As with the existing 1×8 that I would be removing, the new 2×12 rim joist would carry no load above it, but also would not be supported below it by the foundation. I would connect the new 2×12 rim joist to the 6×6 beam as well as the ends of the joists with FastenMaster 4.5″ HeadLok structural screws. The 2×10 deck ledger would then be connected to the 2×12 rim joist with FastenMaster LedgerLok 3.625″ structural screws. Or do I simply flash and attach the 2×10 deck ledger directly to the ends of the joists and the 6×6 beam, forgoing any sort of rim joist?
Here is a picture of what I am currently looking at (the attachment function is not working for me at the moment for some reason):
The 1×8 “rim joist” has already been removed in this picture, exposing the joist bays as seen in the picture. The 6×6 beam was badly rotted from the previous owner’s nonexistent flashing job, so the different-colored pieces you see in the picture are repair pieces that have been tied together.
I hope the picture helpfully portrays what I am trying to describe. Thank you!
GBA Detail Library
A collection of one thousand construction details organized by climate and house part