Cost for partial 2nd floor addition?

Hi All, I have been working on modelling a potential 2nd floor addition for my house and I would love to get a ballpark figure of what I would be looking at to have this built.

My home is a bungalow, with an existing loft. I would like to add an addition above a section of my home that would connect with the existing loft to expand my 2nd floor.

I have attached several photos of drawings and 3d models that I have. The area with the blue lines indicates the location of the proposed addition. At a high level, this would involve ripping up the roof in this section, building directly on top of the existing load bearing walls, installing a new roof and tie-ing into the existing. Also would include plumbing/electrical/hvac etc..

We have put a lot of thought into this, and I can add more details if required - please let me know. But I am hoping to get a ballpark figure for what this would cost.

Any responses would be greatly appreciated. Thanks in advance.