ᐅ Is it necessary to insulate the roof of an older building—YES or NO?

Hello everyone

We are thinking about buying an old building, and the roof is not insulated. There is only a kind of membrane under the roof tiles.

So far, everything looks dry.

Is there a general requirement to insulate the roof, or does this only apply when the house changes ownership? I have also read about a two-year deadline.

I’m quite confused because I would like to know what to expect before a building inspector comes.

P.S. If you want, I can also take some photos. That might be more helpful than anything else. 🙂

Here are two photos related to the topic. 🙂