Isn't an Ikea base cabinet 31.5"? Are you going to the ceiling? That space for cabinet and trim...how much space does sz say it need above?

Ikea doesn't really work with high end built ins.

I think, if I understand the Sub Z directions properly, that the 84" takes into account what it needs above. The base cab is a clever thought. I wonder if I could get it to match up, at least sort of, to the 24" tall cab next to it.

I've got an old rowhouse with a major storage shortage so I'd like to make the most of any storage opportunities -- thus, I am thinking about going to the ceiling.

How much are you leaving for crown? Also are you using IKEA doors or custom?

I was thinking IKEA doors, but not wedded to it. My feeling on the crown was - whatever is left over. I'm trying for a modern look so the crown will be something understated.

First give some thought as to whether you want the built-in installation or the flush installation for the SZ. The specs are a little different depending on which you choose. Next, the base cabs in the Section (I have akuurum) are hung from a rail just like the uppers, I believe. So practigal' side a of base cabs that are all 31.5" high X 24" deep would probably work quite well. I'd go for a two door 30" base and a single door 18" for the most efficient use of space. Consider roll outs. Good luck!

What will be your top alignment height? Use that number and use the subtractive method to figure out what size you need. Doing a built in fridge is hard enough without having the restriction of the limited sizes that are available in a stock line.

As @Livewire said, work your measurements from the ceiling down. Make sure that you check your cutout allowance carefully.

I'm using custom doors so I hacked the Ikea wall cabinets down on two planes to fit between the crown molding allowance and the cutout for the built in fridge. I also had to take into account a partial soffit that I was only able to recess by 5".

The doors will be 18" but the cabinet height is 6" and 12".

How far below your ceiling is your run of planned upper cabinets? If you have 34" north of the fridge, you could hang two 24" wide base cabinets over top of it.

I guess another option might be building a short soffit where cabinet over the refrigerator needs to go, in order to bump stardard upper cabinets forward.

It is possible to hack cabinets to different sizes, but if you want ikea doors to fit, you'll still be constrained to the sizes of the ikea doors. If doors won't fit the custom boxes you need, so that you're using just the sektion "box," the box likely won't match the cabinets. It's also a less finished look. In that case it might look better to mount an open box made from wood and painted to match.