Vinyl flooring installed over expansion joint

Yes… we have read many different things. The floor around the kitchen should be installed. Others say you can safely place the kitchen on the vinyl. Since we were under time pressure, we decided on the latter.

@ " ": The floor elements you installed have a total thickness of about 8mm. This means they can already absorb quite a bit of tensile—specifically compressive—forces without deforming. The "expansion joint" you described can only be a false joint in the screed. It has fulfilled its purpose after the screed dries, which is to absorb occurring tensile stresses in the screed structure without cracking, and afterwards it is irrelevant. That means you did not make a mistake in the installation. I strongly advise against cutting the flooring at the spot where you suspect a relief in a fit of overaction!! Check, this is the best option, very meticulously all around to see if it is hitting somewhere, where the edge gap, into which it can expand its length changes, no longer exists. The second possibility would be, in the case of a continuous (improper) installation through or over all rooms, without intermediate expansion joints, that the room geometry is the reason for the buckling. Then, only in this case, would it be sensible to cut out a strip of flooring of maybe 10mm below the door leaf with the appropriate tool and install a transition profile. But please do not cut the flooring at the spot where the red mark was placed in the photo! That will not be successful, but destroy the overall appearance of the floor without the certainty that the corpus delicti has really been removed! ------------------- Regards and good luck: KlaRa

The floor around the kitchen is supposed to be installed. Others say you can safely place the kitchen on top of the vinyl. Since we were under time pressure, we decided on the latter.

So if it is really installed as a floating floor (click vinyl), then I would suspect the problem there. In my opinion, placing the kitchen on vinyl is only okay if the vinyl is glued. You have completely fixed the floating floor covering in the direction of the kitchen without any possibility for expansion.

What I notice: The (heavy) island is hit by the sun on the ground. Then there is immediately a shady zone. As far as I know, this is extremely unfavorable for floating flooring.

Thank you very much for all the answers. So this is the situation. This bulge or elevation (about 5mm) is basically only on the left side of the island (about 1 meter long). I had assumed that it has to do with the expansion joint. Through all the answers (especially from pacmansh and KlaRa) I am now quite uncertain and think that it might have something to do with the island. Regarding the sunlight (temperature difference) I rather doubt it, since it also does not change. What could I do in this case now? What would be your opinion? I have also checked everywhere to see if there is enough space to the walls. That is definitely sufficient.

So my only competence in this area is that I once installed click vinyl and will use glued vinyl in the new building (kitchen island on top). With click vinyl, I would have laid it up to the island. Not that I want to be called an expert.

But I think everything speaks for the problem being with the cabinets and the kitchen island. Do you maybe see a possibility to cut something out in the area under the island, which is covered by the baseboard? That would probably be the first thing I would try.