When you say the builder messed up, is this a custom build or a tract build? What do your plans show?

Yes it will look odd

How does one get 8'4"? They use an 8' 2x instead of a 92-5/8" Stud. (add one 2x on the bottom and two on the top for total, less 1/2" drywall).

I've only seen that once by a DIY. Not a problem structurally but hmmm.

I did a 8'4" second floor on one house.

It was a last minute move, resulting from lifting the first floor to 10' while trying to maintain the highest second floor ceiling within the constraints of the roof height limitation.

The higher second floor may not be evident at first glance.

If you contracted for a 9' first floor, that's what you should get. Assuming you caught this in the first floor framing stage, time for a do-over. Not as big a deal as the builder will claim.

Is 9’ in your contract? Is this clearly a builder mess-up? If so you are entitled for them to fix it regardless of how expensive it will be. Or at a minimum, negotiate compensation for this egregious error. If I was paying for 9’ ceilings and had a contract that said the builder would deliver 9’ ceilings, I’m not sure I would just exchange with taller 2nd floor ceilings as a fair swap. Resale value of your house will be impacted.

I can't think of a reason the house would look odd. I often put the rafters on the attic floor deck to raise the height of the second floor wall so there will be space for a frieze board under the eaves.

But the second story windows should be a bit shorter than the first floor windows.

Correcting the height of the first floor studs can be a very expensive task since bearing studs cannot be spliced. I did it for a renovation once when adding a second floor by eliminating 3 out of 4 floor joists, tripling up the remaining joists and placing another set of joists on top of them before building the second floor. The old joistss got wrapped with drywall and crown moldings added.

A top heavy proportion isn’t usually desirable. It’s one of the sore spots for many of the home designs posted here. It more usually focuses on a big fat roof. A tall second floor over a short first reminds me of the way some coastal builds are done where the living areas are elevated, and below is closed in. It often looks oddly proportioned, without good design to aid it.

"I wanted ceiling on the main floor to be at least 9' but the builder messed up"

What did the drawings show? What did the contract state? Anything in writing? What is the builder proposed fix for this?

IMo there is no real advantage to 9’ ceilings in bedrooms and I think the effect would not be worth the money . I am however curious about 8’4” ceilings . I think you need to share a lot more info as to how this happened. BTW in this time with heating and cooling costs going crazy be happy you have lower ceilings IMO

I would not want or be happy with lower ceilings if I lived anywhere with a warm climate. Even really old houses built in warm climates had 10ft+ high ceilings and there was a good reason for that!

Actually Patricia if you live in the south, there is a very good reason for 9 or even 10’ ceilings. Heat rises. And lower ceilings would absolutely make the rooms warmer

Not sure I agree with any of this height/climate issues. Old houses had higher ceilings in the south because they had no a/c. In the days of a/c, the ceiling height doesn't matter much. If you feel warmer, there is a control on the wall to fix it. With lower ceilings, you have less heat gain from the outside so it might be cheaper to keep a lower ceiling house at a colder temp.

Either way, lower ceilings = smaller windows (all else being equal) which absolutely lowers cooling (and heating) costs.

As far as prices "going crazy" that really depends on climate/location/design etc. I have very typical 10/9 with one room up to 14 (but not at the walls). My HVAC is completely covered by a $18k solar array for our 3800 sqft. With interest rates at 2.5%, that is like $70 a month (and that includes appliances/hot water/lights/computers etc....

"Higher second floor ceiling...?"

Yes, of course you can do anything you want and can afford.

But...

Why are you allowing the contractor to proceed if he "messed up"? Was the first floor ceiling supposed to be higher? Then make it what it was contracted to be.

What's on the second floor? Is it limited to bedrooms and bathrooms primarily? Does your contract call for a certain ceiling height on the second floor?

The frequent ratio of first to second floors, with living spaces on the first and sleeping spaces on the second, is often a greater ceiling height on the first and possibly a lower ceiling height on the second. What is considered "best" heights is personal choice.

I personally prefer 10-12' lower floors and 9' upper floors. I just don't personally care for 8' ceilings--just not enough spatial variety for my taste. Your taste may vary.

Make the second floor whatever you, your budget, taste and contract allow. BUT...only after you get the first floor at the contract height.

That's an unacceptable screw up.

Sounds like the builder did NOT take into consideration the mechanicals being run in the ceiling and discovered the 'oopsa' when they enclosed the main floor ceiling...thus loosing 8" of ceiling height (sounds just about right for mechanical and HVAC returns).

Please post photos and a few more reasons as to how this happened.

Personally ('cause I couldn't care less) I would ask for a BIG discount (what was the amount you paid to up grade from 8' - 9' ceilings????) on what has been finished.

There are plenty of ways to compensate you for this oopsa. I'm a miser (who likes the envelope to be solid) who is happy with money in her pocket at the end of a build. I will cut 'finishing costs' over envelope costs any day.

So long as the build is solid (everything else done properly) and you can ACCEPT the difference, I would negotiate a discount. It can be substantial.

It will not look odd or disproportionate. There is not a huge difference and who is going to measure the height. But if you contractor has done something you did not sign for then he is responsible to make it right.