A small bit of separation would not be a concern to me, but that much would. To me this is a sign of a lot of settling in the house, or cabinets that were not properly affixed to the wall in the first place. The first thing I would be doing is to get out a level and check the floors, walls, and cabinets for plumb to try to identify what's moving. Do you see evidence of settling or cracking occurring elsewhere in the house?

Do you have in progress pictures of the cabinet installation?

Just because the stuff in the house is expensive doesn't mean the house was built well. A poorly built house will shift a lot. Especially if the foundation is bad. Do you have a lot of other cracks in your drywall throughout your house? Look around your house ceilings, around windows, where you think the main beams are, ect.. Is the cabinet screwed to the studs? If the cabinet is screwed directly to the studs with proper screws, then the cabinet shouldn't move at all. Looks like he missed them.

Another issue with a poorly built house is when you do put more expensive stuff in it like a lot of stone, the weight could cause the floors to sag and walls to bend. This has really become the norm in america as, I'd say, 90% of new home are built like crap. You know, the neighborhoods with houses nearly identical, stacked side by side. Built cheap, made to look nice on the inside, wife goes, "I want this house", sold for a lot of money. LOL The other 10% would be custom built homes.

Go look in your basement. If you have these so called "engineered joists" or they are no thicker than 1-1/2 inches, then your house is built like dog _ _ _ _.

It usually happens when the cabinet is screwed into a sheetrock instead of catching the studs and it pulls away from the wall, or if there was some sort of a shim on the bottom which got knocked out when kitchen floor was installed but in this case, you would see the cabinet come apart at the corner/s on the inside if it was properly attached to the wall.

Outside wall? Location? What is the wall height?

The reason I ask, is that in a heating/cold climate exterior walls can bend outward in the middle like when a truss uplifts in the winter. The taller the wall, the wider it bends at the base cabinet joint, You dont notice on uppers because they move with the wall, but it becomes noticeable at the base cabinets because the backplash moves with the wall, and the base cabinets try to go, but can only go so far before the fracture between the tile backsplash and the countertop occurs. a 10 foot tall wall in the middle of the winter, will move outward in the middle about 3/8 " in a true cold climate like mine, where it was -17 last week. They do seam back togwther as the weather tempers... Im not saying this is whats happening in this instance, but the picture to me looks very much like this situation.

It sounds like the cabinets were not properly screwed to the studs. Maybe these morons used wall anchors which is no where near adequate enough. He's probably acting like that so you don't start asking for some of your money back for doing a shady job. A properly secured cabinet shouldn't move even if the shim did fall out.

Or maybe they just used normal screws. Now because of the weight their getting ripped through the back of the cabinet. They need to use screws like the one pictured. It has a big head on it to properly grab the back of the cabinet.

I took a closer look at your cabinets. They are the extremely cheap kind. Their made out of that garbage MDF stuff. Maybe the doors are real but that what they do. Real wood doors for the look and feel, everything else is garbage. If he used normal screws. They 100% ripped through the back.

OP has not offered enough information for anyone to respond with a definitive diagnoisis. We need to know wall framing detail, floor support detail, direction of the floor joist, and other elements adjoining wall system.

The end wallof the vanity, is an outside wall, correct. Where are you located? What state?

slrohrer-

If you lean your hip against the cabinet, is there movement? Can you push it back against the wall or not?

If nothing else is moving in the house, and you have really inspected that, then the cabinets were not installed properly and they need to be done right. I don't care what the builder whines about. You paid the money for a high-end job, so you deserve at least a mediocre job and this is just bad. Let the builder be mad, but you stay cool, and simply stay firm without hyperbole. You say "I don't want a "fix" I want these cabinets installed properly along with the backsplash which isn't done right either and has been impacted by the workmanship of the cabinetry." "Let me know if you need additional information." done. Before you engage with the builder too much, check your contract for the specification details of the cabinetry. It should state what type "box" will be used and what materials will be used. That will arm you with good additional information. Always are yourself with data before entering into "Tete-de-tete" with builder. He/she knows the contract. They are obligated to meet standards and specifications delineated in the contract. If you had a separate document from the kitchen supplier where you signed off on specifics, reread that and see what it commits to. All these documents are vitally important. Many use the "trust" method with builders and that is a dangerous game. You must be educated and involved in the details. Best of luck. This is a mess and it must be solved to your satisfaction.

slrohrer-

Good luck with this. I'm hoping that adequate, permanent fixes are possible, and that they are fairly easy. I think it's premature to make dire predictions about quality of construction or installation, but I will be interested to hear what you find out.

When cabinets are in the floor plan, they often install wide horizontal blocking between the studs so that there is a continuous band of wood to screw the cabinets into. It saves a lot of time and trouble, instead of trying to find a stud so that the final installation will hold the weight of a full cabinet. This is especially true for securing the upper cabinets. Do you remember seeing that type of blocking in the walls when the house was framed?

Bruce

@bruce, they only do that if the kitchen has been gutted. Its not that hard to find studs anyway. If you cant find it with a stud finder, you can use a long small diameter nail and keep punching it through until you find one. The walls gonna get covered up anyway. Then measure 16 inches from that one.

I have been in the cab business for 30 years. we see this separation a fair amount, this degree once and a while. On mainly exterior walls also. True the better grade of cabinet, the more stable it is. Unfortunately higher grade levels of cabinets ( all materials in general going into the home) are not in the main stream budgets. You have low, medium and high end home budgets, in turn low, medium and high end materials. I have found that it is typically not one specific cause but a combination of floors, walls and installation issues. Honestly, mainly the floors sagging. It doesn't take a lot of sag to cause a problem these days. Sometimes it's the perfect storm so to speak. It seems to be more common when house is built during summer ( more rain makes it worst) ( 2018!) then when winter sets in and the heat turns on walls, floors dry out and shrink, move, etc. its gotten worst with the houses being built faster, pre-finished flooring which is not typically installed before cabinets like sanded and finished on site floors which are ( higher end budget, longer build time). So not only is the cabinet built up on 1/2" to 3/4" material then it must be shimmed to level. Then set 700 - 1,000lb granite on top of it all.

Ive seen this problem and shown the floors sagging toward center of kitchen 1/2" in just 36" from wall, usually toward a nice island also with granite. Popular open floor plans have also made more expanses for joists to contend with less support. Yes, accommodations are made in engineering but you still get more movement. . Cabinet is a 90 degree sqaure box, though it is attached to wall studs the bulk of weight still falls on the floor. Floor drops, front of cab, shims etc drop to, upper back corner of cab comes away from wall some, even still screws in studs, again Remember the granite weight To. All that said, we still repair but quite often it returns due to these other factors. It's not always easy to nail down one main cause. We are always looking for ways to prevent this from happening. We are seeing less of it with homes that do add blocking between studs specifically for the cabinets, but still happens occasionally. Because there's still movement in floors and walls. . FYI: it never happens on concrete slab floor jobs, or higher end 1k and up, custom homes.