Our company is considering a project involving raising a building floor 17.5" by pouing additional concrete on the existing ground concrete floor (foundation). The building is a single storied/octagon shaped building whose only supporting system is its 2x6 wood stud perimeter walls. The client (owner) does not want the building's structural integrity disturbed but has specified a design whose jest involves removing the bottom portion of the walls (cutting and removing a portion of the studs) and replacing them with cider blocks. The wall's remaining top portion will then be supported on the cider blocks and the new concrete can then be poured ontop of the existing floor 17.5". My problem is I do not want to disturb any of the structure main support system and would like to know do you know of another way this maybe done such as removing only the bottom panelling of the wall and just pouring concrete (engulfing the studs) up to the desired level or still utilizing the cider blocks by finesseing them (first removing sections of the sill or bottom plate) between the studs??

Is it a requirement that the building maintain the current ceiling height or could it drop 17.5" in height and still be acceptable?

Yes, the building height will remain the same in essence compressing the clearance from the floor to the ceiling by 17.5".

Then you do not need to cut out any lumber. You can't just pour 17 " of concrete on top of existing concrete. A perimeter wall 17.5" tall can be built around the edge using PT lumber or CMU. Pour and compact gravel and then pour a 4-6" slab floor. However this would have a very negative effect on door openings

... along the same line of thinking as mine, I just needed validation and/or another's perspective.

Thanks for the response.

How wide is this building and what is the reason for needing to raise the floor, seems like a waste of money. Cheaper to lower the ceiling.

It is relatively small--28x28 but octagon in shape. I am not sure at this point why the increase in floor elevation requirement.