Timber panel construction - exterior wall thickness = 10 cm sufficient?

That looks more like a 20-25cm wall.

But where can you get such nice houses for this price?

Please take another look at this from a different perspective.

The windows slightly protrude inward.

You can already save a lot on the insulation of the cold roof. The costs are also manageable there. And inside, for example, you could insulate the walls in the upper floor very efficiently with wood fiber insulation boards. Only your budget is already very tight when I think of the costs for floors and electrical work.

Minimum purchase price: 125,000 our budget is 200,000

But where can you get such beautiful houses for this price?

I am beginning to understand that the OP’s remark was meant that the purchase price unsanitary is only X below the budget. (Also) I see it rather that the delta Y between the price and the market value is more relevant. One will only be able to give some advice "more precisely" when more facts are known. Who gives – since a demented previous resident was mentioned – the agent the assignment and the specifications regarding the price: the owner herself, or a guardian?

I am beginning to understand that the OP's remark was meant to say that the purchase price without renovation is only X below the budget. (I) also rather see it that the delta Y between the price and the market value is more relevant.

One can only give some advice "more precisely" when more facts are known. Who gives – since a demented previous resident was mentioned – the agent the order and the instructions regarding the price: the owner herself, or a guardian?

The woman was deceased and it was apparently offered for sale by the heirs.

An expert created an appraisal and arrived at a total value of €120,000.

You can save a lot on insulating the cold roof. The costs are manageable there as well. And inside, for example, you could insulate the walls on the upper floor very efficiently with wood fiber insulation boards. But your budget is already very tight when I think about the costs of floors and electrical work.

Those are exactly our concerns.

We had the inspection appointment yesterday and are supposed to submit an offer by this Monday. We find it very short notice. We think it will be difficult to find an expert who can help us on such short notice.

The woman had passed away and it was apparently offered for sale by the heirs.

Then I hope there are only a few heirs. The only greater scourge of humanity than "brokers" are "brokers and communities of heirs."

We had the viewing appointment yesterday and are supposed to submit an offer by this Monday.

Tomorrow is Friday. If you have access to the building file then, we can still add our two cents over the weekend. If you can research the history of sales efforts, that is very helpful. How much "competitive pressure" do you have?