Can I use a wider sill plate than what was originally used?

Question

I have a rotten sill plate. I believe it is a 2x4.
It sits on a  6 inch cinder block and only uses the the outside 2 inches of the block.
             __________
            |          |
 ___________|__________| <-- existing 2x4 sill plate
|                 |
|                 | <-- 6" concrete block wall
|                 |

I have access to the other 4 inches through my crawl space. Is there a reason I can't use the inside 4 inches for a wider sill plate?
  _____________________
 |                     |
 |_____________________| <-- new wider sill plate
|                 |
|                 | <-- 6" concrete block wall
|                 |

Lee Sam · Answer

The sill plate is used as a transition from the wood walls to the foundation for vertical loads AND horizontal (shear) loads.
Yes, you can use a new sill plate placed on the inside of the wall (with anchors in it to hold it down to the foundation wall,) but the exterior wall sheathing needs to fasten into it too.
Horizontal shear is to resist wind and seismic events....and keep your house from floating away if it floods where you live.
Do you live in a high wind area or seismic active area?

Can I use a wider sill plate than what was originally used?

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