How do I replace floor joist that are mortised into a brick masonry wall? The building was buit in the 1800s. The existing joist are a true 2"x12" and I want to replace them with a nominal 2x12.
Simplest way is to remove the existing joist by cutting it out, providing adequate temporary support to the floor above. Install a new joist using metal support brackets appropriately anchored to the brick. This may require epoxy anchors, lead shields, or similar anchor devices, and assumes the brick is structural and in good condition.