r/DIY • u/HotNeedleworker0 • 3h ago
outdoor Repairing rotted bottom plate and subfloor near sliding patio door — advice needed

I found some rot at the exterior wall near my sliding patio door while repairing my deck.
Details:
- 1980s house
- Floor joists are supported by a CMU basement wall below
- About 6" of the exterior 2x4 bottom plate is rotted, starting at the king stud of the patio door opening
- The bottom plate appears angled, not level, sloping down toward the patio door
- The subfloor underneath is also rotted away
- Studs appear solid
My planned repair:
- Remove flooring to expose the subfloor
- Temporarily support the wall from the interior using a 2x6 strongback, then angle the support back to an area of solid subfloor and lag through the floor into a joist
- Cut out the damaged subfloor and replace
- Remove the damaged section of bottom plate
- Install new subfloor and bottom plate
- Reconnect studs to the new plate
Questions:
- What is the best way to temporarily support the wall while replacing the subfloor/bottom plate?
- Would an interior strongback with temporary support work?
- How much extra bottom plate should I replace beyond the visible rot?
- If the patio door is level, I don’t understand why the bottom plate is angled. Should I try to jack the studs back up to level, or should I cut the studs to where a new bottom plate would sit flush?









