Was this linoleum flooring installed correctly, that is, professionally?

It is always great when craftsmen quote a DIN. Let him show up again with this DIN and prove it to you. Because he definitely does not have this DIN at all. And 1 minute of googling shows that what is shown there does NOT correspond to the state of the art. Consequently, you must formally! (no email) notify the defect in writing and of course not pay. If he cries, HE must provide proof that the work was carried out correctly. He could do this, for example, by bringing the DIN and showing you the relevant passage. As it looks, you could do it yourself and save a lot of money. If chairs wobble, the DIN is definitely not complied with ^^

Just because the DIN was not followed at one point does not necessarily mean that the craftsman will lose in court. If it is a single point where the DIN was not complied with and the rest is fine... it is unlikely that a judge would decide against him.

But first, I would also shorten the invoice... the next step is then up to the craftsman, and you can still consider it later ;)

In the pictures, it doesn't look like it's only in one spot. The pictures might also be taken from a very unflattering angle, and it's certainly not easy to lay something so straight, especially with the wall molding, which immediately shows every little unevenness. Once the adhesive is set, can it hardly be lifted, properly underlaid, and laid down again?! Then a partial payment makes little sense, since the damage is even higher than the invoice to be paid (estimated damage x ~3 can be withheld). First, the stuff would need to be removed (cost) and disposed of (cost). And then start all over again...

Possibly, a solution would be to settle for a lower payment. But then it should be worth it. For that, prices would be needed.
Do you have the price for material and labor? Can the flooring be lifted and used again?

Linoleum is always glued down, the seams welded. That is not suitable for every home and yard service that sometimes installs laminate. That is advanced skill, a clear case of being overwhelmed. The company. Karsten

Hello,

I set the deadline for defect remediation by registered mail. Until 09/24, as I will only be back from vacation on the 06th.
I had received the invoice before completion; the maintenance joints and connection joints of the baseboards were not yet finished.
The floor looks like this all around at the wall.
You can also see “snake lines” of the adhesive or leveling compound at 2 spots and small waves in the floor everywhere. In addition, the floor exceeds 4mm at at least 2 places.
Furthermore, there is an approximately 2.5 meter long elevation in the floor. If I lay a 2.5m-long straightedge at a 90-degree angle with one end on it, I have about 12mm of clearance at the cantilevers about 2m away at the other end until the floor...

In total, it is 25sqm and the invoice amounts to €2,250.

so for just under 100€/sqm you can definitely expect a completely different quality. nordlys I think put it spot on: the employee simply couldn't do it. I wouldn't pay him anything for it. rather even compensation for costs of removal.

what does the material cost?