Am I legally on the safe side regarding the work contract and scaffolding?

Hello,
of course I did not respond to an ad in broken German on a dubious classifieds portal and already transferred 140% in advance...
This company has been working for my own employer for years, I have also known the boss for a long time and other construction services have already been handled
I am really concerned about the legal certainty regarding illegal employment and occupational health and safety/ insurance coverage. So once again the question: Is a contract for work and services over a defined service sufficient?
Do I have to rent scaffolding (because of some UVV inspections or similar) or can I use my private one?
Thank you

So, once again the question: Is a contract for work for a defined service sufficient?

Formally, you could even commission it orally. So yes, the contract for work is sufficient – you know the risks of the foreign company (I have no problem with it either, I have even signed contracts in Polish and relied on the contractor’s word).

Regarding the second part of your question, I have no answer due to lack of legal expertise. Lay opinion is that it is okay if you include it in the contract for work. If you rent scaffolding, you also make it available to the contractor privately – with all possible consequences. Therefore: go for it!

The scaffold is supposed to be for roofing, right? Layman's opinion: you need a setup for roofer work including a safety net, if you don’t have that and something happens (a visit from the [Berufsgenossenschaft] is enough), you have a problem.