It’s still a split level. Not worth spending that kind of money on the least desirable home type that exists.

Thanks - but house prices are insane and this is the easiest way forward.

You are not looking to "dormer" the house, you are adding another level.

I'd consider a Prairie Style House design. Although not usually a split level, I see the possibilities.

Remove the bay window, or convert to a box bay, fix the bedroom windows above the garage. No gables. No arch top windows.

And someone spent a bunch of money on that white fence, but it really needs to come down or be replaced by one that blends in and is not plastic.

We love our split level. We added a level over the main floor, and extended so its each level.is a nice size, but ita still a split, with 4 levels and a basement. It is so nice that all areas of the house are easily accessible and connected. Wherever family members are they never feel too far away, it's a very cohesive house plan, and at the same time there is separation so when pple are sleeping etc noise doesn't travel because the levels aren't directly on top of each other. I dont know why it's the 'least desirable', I think when done nicely it has a lot of great benefits. Obviously if stairs are difficult it isn't for you but for a many families it lives very well

I miss our split-level.

It is hard to add up to a split, and changing the style altogether is tricky. In our old neighborhood, a couple of houses were redone well, and some were redone poorly. It works best when the addition is on the same scale as the original. That is, if the original house has 8’ ceilings, so does the addition.

You will need to rip off the roof, and add a floor. That is a darn expensive endeavor. On the order of building three fourths of the house new. You will need to move out for it, for at least 6-9 months, so say a year's lease cost's added to that. You really should explore what 3/4 of the price of your existing house, added to your sales result, would give you, in the current market.

I would not call a split level home undesirable. They are very nice houses and function very well to live in. I have had one in my life time. Most people who have them love them. That said, I do hope you are aware that this addition is going to be very expensive. It may be better to sell it, and buy another house, that is larger and meets your needs.

Your architect wants it to become a 90's McMansion, I think ppf is spot on for looking at Prairie Style (this one popped up on google and has vaguely the right massing)

For Prairie Style architecture, get inspiration from the source. Look for works by William Drummond, Walter Burley Griffin, William Gray Purcell, Louis Sullivan, Parker Noble Berry, George Grant Elmslie, Marion Lucy Mahony, Francis Barry Byrne, Frank Lloyd Wright, and others of that time period.