Bought a modern house. Roof not well insulated?

It looks to me as if the snow on the left has mostly slid off (Abrisskante). However, it certainly doesn’t hurt to take a look at it with a thermal imaging camera. Between the Abrisskante and the solar collector, I see very little snow. In any case, I would monitor how it looks with further snowfall.

In my settlement, there are some houses with completely uninsulated roofs, where you can see the top edge of the heated floors clearly drawn with a ruler. That is something different.

If more snow stays on one side of a house than on the other, it can be due to a thousand things – sun position, wind or vortices that blow snow on or away, the room on the left is heated and the room on the right is not, etc. If snow stays on one house and not on another, there are already mentioned other reasons for that.

So yes, if you have a bad feeling, get a professional who measures it. And no, a cellphone with a thermal camera app is not a professional measurement.

Is the attic then inhabited and heated? Also at the neighbor's? Because even with good insulation, that can explain the difference to a neighbor with an unheated attic. As soon as there is a temperature difference in the house, there is also an outside, because 100% insulation is physically (almost) impossible.

Thank you for all the contributions. The attic is indeed converted and heated. Above that is a small loft. I quickly took some photos through a gap to the loft with my phone. It seems to be insulated after all... only the intermediate ceiling not really. There is only loose insulation wool lying on it. Should I spread it out on the intermediate ceiling?

The attic is insulated. Then the intermediate ceiling does not need to be insulated.

Don't worry so much, it all looks okay. Maybe your outdoor lamp emits too much heat ;)

Shoddy work isn't when the owner has no documents. Shoddy work would be if the contractor did not build correctly. And the owner cannot (know) anything about that.

The thermal imaging camera should, however, be operated and interpreted by someone who knows something about that. If a layperson holds the camera on it, it will probably be "Oh God, oh God, the neighbor’s roof is cooler!!" Son gable roof has quite a bit of surface area and thus a significant part of the thermal envelope, so a considerable amount of heat is lost there. 68 kWh/m²/a is also not exactly passive house standard. According to the current building energy law, you wouldn’t be allowed to build that today. The neighbor may have built to a better energy standard or simply heats less. Who really knows that for sure.