Many times long tall cabinet doors tend to warp. Consult the cabinet manufacturer.

/\ warping would be the main reason not to do oversize wood doors, but might not matter if they are some type of composite with wood veneers.

Don't think it will look monolithic without glass, but that is personal preference. I have stacked white cabinets with 12 ft high ceilings and went with solid doors, but the view from the family room is of the large triple windows. You would have to be inside the kitchen to really notice what was on the front of the upper stacked cabinets. That also means that you would barely see whatever you might put behind glass. If you are feeling brave you can show the plan of your kitchen and great room!!

KD seemed to indicate that the warping would be prevented by stacking two doors, 30/18 or 33/15--even if there is only one box behind them, and with the doors attached so they open as one. That seemed more convenient to me, and less expensive than two stacked cabinet boxes. But I definitely don't want warping!

There aren't that many upper cabs because there's a big window on one wall and a hood on the other wall. But there are still things to be worked out, eg, the cabs over the fridge and ovens are not even with the "break" in the other cabs, and I'm not sure if that will bother me. It does when I look at the drawings. (Also I'm not sure the steam oven is at the right height.) I have enough storage that I might get rid of the corner lower cab, depending on what it costs. So, I'm posting these with the caveat that they are still in process and I have yet to dig down and make sure the cab layout is what I want.

The measurements are not all shown on the main layout--the L is 16x14, the aisles in the L are 4 feet, and between the island and that standalone cabinet is more like 54". Anyway, it's more than 4 ft there. The main sink is on the north wall. There are windows north, west and south. The living room is directly south. East is the mudroom area with PR, laundry, pantry, garage, and a mini admin space. There are doors to a large west terrace just below that separate cabinet across from the island, as well as from the breakfast room.

Ignore the kitchen layout in the plan that shows the great room; it's outdated.

I don't like the ratio of the stacked cabinets you show in the elevations. It makes the bottom ones look really squat. I can't read the dimensions in the elevations.

The way your kitchen is viewed I probably wouldn't bother with glass, unless you already own things you would want to display up there.

@chispa I agree about the squat look. I had the measurements wrong in my post--it's 30/24 as pictured, and I think the upper-uppers should be smaller. Plus, the door is shown as Shaker when it's really going to be slab. I haven't found an image of slab front cabs that are wood, rather than painted, in a stacked arrangement. I think the doors would be veneer? But I'm not sure. In my current kitchen I have solid cherry doors. I'm not sure what a veneer looks like in a natural wood finish. I think you're right about glass; the stuff I want to display will be on shelves elsewhere, not in the kitchen.

When planning my stacked cabinets, I learned from several pros on here about using ”the golden ratio”. Basically you want the ratio of the stacked (or stacked-look) uppers to be closer to 2/3 to 1/3.

I think your plan shows a 24” stacked on top of a 30”, which is closer to 1/2. That is why it makes it look kind of top heavy and like the bottom one is being squashed from the weight.

See rule # 8 on this site about the golden ratio.

https://www.mainlinekitchendesign.com/general/kitchen-design-style-tips-pros-know/

See the featured comment on the links from the dearly missed Sophie.

https://www.houzz.com/discussions/5121280/photos-of-36-with-15-stacked-kitchen-cabinets#n=6

https://www.houzz.com/discussions/4270879/9-foot-ceiling-stacked-cabinets-or-one-tall-door#n=22

@rebunky, thank you, that's very helpful! I was thinking 36/18 would look better, but I wonder if they can do 36" tall cabs, or if that is beyond the allowable height for warping.

Size the lower doors of the wall cabinets to at least the height the cook(s) can comfortably (acceptably) reach, and the upper door of the wall cabinets the remaining distance. The best kitchens win taste tests not beauty competitions.

We’re doing slab-front cabs with 9-foot ceilings too and we’ve looked at all kinds of options. Our KD showed us several stacked configurations, both with and without glass. During that process, I realized that I won’t use cabinets that high. I can’t reach them and we’ll have plenty of other storage space. But I also didn’t want to leave empty space between the cabinet tops and the ceilings. I think that would just collect greasy dust. And if I’m honest, I’ll clean up there maybe…never. Talked it over with our builder, he suggested a coffered ceiling to fill in that space. That seems a little more of a traditional look than I’m going for. Then I found this picture of soffits extended past the cabinets with puck lights installed. I like it.

The prep sink on the island is not in a location where it gets used. You can drop it. If you want one drop the size to a 24" base with a 21" sink.

@Mark Bischak, Architect, if you mean I should be able to reach the top shelf of the lower cab...I'm short! I have a toe-kick stepstool in my current kitchen, and I need it for everything above the second shelf. The way-up-high space would be storage for infrequently used items. The KD is suggesting that the upper door will open along with the lower door--two separate pieces to prevent warping, but invisibly attached. That saves me from having to get separate cabinet boxes for the upper uppers. Sounds like you recommend separate cabinet boxes, though?

@Sofia thank you for the suggestion! Like you, I don't have decorative trim since this is a more modern style. I could do a short soffit or a plain trim piece. In my current kitchen I fought to get rid of the soffit, but that was with an 8 ft ceiling in a traditional style room, and I also really needed that upper storage space, which in the new kitchen won't be crucial.

@dan1888, I see what you mean, I could probably make that prep sink a little smaller, as long as certain things will still fit. I do want one, though. It works for the way I plan to use the kitchen.

Your kitchen designer has a good idea, but you could still have one cabinet box and two separate doors.

If they are a frameless cabinet, here is still potential for the wall cabinet sides to warp in a long unsupported height, depending on the cabinet's construction and installation. An intermediate fixed shelf where the doors meet could alleviate the potential issue.

What do you think about the cabs above fridge and ovens not lining up with the uppers next to them? Does that matter?

"Does that matter?"

Only if it effects your cooking.

@Mark Bischak, Architect Might burn something b/c i'm staring at the upper cabs and not at the pan

Is it too late to add a suite for a cook to live in the house design??

@Mark Bischak, Architect why not? I'm already out of money anyway, what's another couple hundred square feet? 🤡

Good point, although they would probably be staring at the upper cabs and not at the pan too.

You'll get over the fridge cabinet not lining up with the other cabinets. It happens in many kitchens and you probably never noticed. I noticed on my elevations, but not when I'm living in the kitchen.

Did you mention something about your steam oven being too high? Just make the drawer below the ovens shorter and lower the stack. The drawer does not have to be the same size as the standard drawer stacks next to it. Don't let symmetry OCD beat ergonomics!

@chispa thank you for that! otherwise I will have a perfectly symmetrical kitchen where I can't reach anything, my pots don't fit, etc etc. And you're right, when I'm standing in the kitchen, I would have to be looking for it to notice.

With the steam oven, I'm not sure what is the most comfortable height. I know i don't want steam in my face when I open the door, and I'm short, as mentioned. I think it's a little too high for me. I think I'd be reaching in to retrieve a pan slightly above my shoulder height, rather than at or just below, which seems better. So, yeah, I'll make the drawer shorter!

I have tall stacked-ish slab cabinets.

I don't want them to open with the lower ones. I don't need to be reminded that I have a punch bowl...

Good point, @Fori!

A 24" undermoiunt sink has a 21" wide by 18" front to back interior. Nothing in a kitchen will need larger. That size, call a 24", will fit in a 24" sink base. It can even use the cabinet sides for support. . .Your main prep/work zone will be between the frig ad the primary sink. I'd want more. I'd forego symmetry for more space there by reducing the sink size to 24" and moving it to the righjt some. You could gain 12" of added counter. You need a lighting plan with task lighting cans and under cabinet. Not just ambient.

Your kitchen designer is way more of a cabinet seller than a designer. They font understsnd anything about proportion. Or fillers for clearance against the ceiling or walls. Or appliance issues. Or standard workflow sequencing.

You need an actual kitchen designer and not a cabinet seller.

I think the design of this kitchen (and house) has already traveled a long path.

@Fori I'm considering having the doors open together because it is less $$ than having a separate cabinet box for the upper-uppers. So it's primarily about saving money. But yeah the stuff I store way up there will be what I don't use/need often--though I also have a decent size pantry closet for things like that.

@dan1888 If I can make the sink base smaller, I will. Already did that with the clean-up sink base (not reflected in the images I posted--plus that sink should be an apron-front). Regarding the main prep area, the way I use the kitchen, my main prep will be on the island to right of prep sink, and on main L to left of rangetop. The area between clean-up sink and fridge is for toaster and coffee pot, sandwich-making, etc. (so is the opposite side of the island, where the m/w is). That way we don't get in each other's way. I don't object to the sink being off-center, since it's the window that will be most noticeable from the living room, not the sink. But, if I move the main sink to the right, I have to move the d/w to the left of the sink and probably put the trash on the right side of the sink. Not bad in itself, b/c that makes trash convenient to both workspaces. But it means people will constantly be heading for that corner to reach the trash which seems bad, I think trash is better near the outside of the L. (And, I'd need to make sure cabs are still the same width on either side of the window.) [Edited to reply re the lighting] We have a detailed plan from the architect that includes all the layers of lighting.

@User I hear you. I've heard tell about this unicorn--the KD who is not a cabinet salesperson--since my first kitchen reno a long time ago, which I mainly planned myself with excellent input from folks here (and was happy with the outcome, given the constraints I had). I have not yet met that unicorn. The KD working on the current project is supposed to be one of the best, was recommended by my architect, clients love them, etc etc. And still I have no illusions--this person is primarily selling cabinets, and I'm going to be the one to make sure my idiosyncratic needs are met. (The goal of the current location of appliances and sinks is to meet those needs.) I welcome advice, especially when it points out mistakes I might miss.

@Mark Bischak, Architect Yup. Even so, I think when I posted an earlier version of this kitchen design, I had either not yet met with the KD, or I didn't have a real layout from them yet. Now I do, and still the cabinet arrangement is not set in stone, I'm sure I'll be changing some things. The overall house design is pretty much set, though, which means the windows are set. At least, until we get the builder estimates I expect any day now...

"get the builder estimates I expect any day now..."

Do not venture far from a place to sit down.

@Mark Bischak, Architect My fainting couch is ready

How would your workflow go if you rotated the island 90*?

Thank you @Kristin Petro Interiors, Inc., i will check on that!

@dan1888 We did play with positioning the island horizontally east-west, but then it impedes traffic leaving the breakfast area, unless it's a lot smaller. It lost some utility that way.

Here's an updated image showing slab front cabs and with the ratio corrected. Apparently the original idea was to line up the bottom of the upper cabs with that short upper window, but it's better not to: