Planning of the barn conversion

Hello everyone. I am completely new here and need help planning the conversion of our barn. Current status: - I, 25, can do almost all kinds of handiwork – and have already successfully done almost everything - Father is equally skilled in handiwork as I am, will help us completely - Father-in-law is a master bricklayer, who would also help us completely - No time pressure, but want to do as much as possible ourselves The barn is located on my parents’ large property. The footprint is roughly 15x10m (not quite rectangular). The rear wall of the barn extends about 4m into the slope behind the barn. There, a terrace leading into the garden from the first floor is to be created. There will be 3 floors, whereby one half of the roof may be slightly flattened to gain more space. If possible, some of the existing beams should at least remain as decoration. The entire front part consists of approx. 60cm thick sandstone. In principle, we want to insulate the walls as little as possible – in our family there have already been too many cases of mold, even though everything was insulated by professional companies. For purely aesthetic reasons alone, we want to be able to see the sandstone both outside and inside. The rest of the barn, which was extended, is built of hollow blocks – these can be insulated as far as I’m concerned. The rear part of the barn, which is built into the slope, consists of the hollow blocks – here one has to consider the risk of penetrating moisture. As far as I know, there is no historic preservation status. The house will be connected to an already existing and more than sufficiently sized heating system. Can anyone give us more detailed information about the insulation? What costs can be expected for such a barn? Many thanks!

I would immediately bring an architect for renovation/conversion on board at the first place. Firstly, he knows what is energetically possible and allowed, secondly, he can say more about the costs after he has created an existing plan.

Best regards, Yvonne

A conversion using existing building parts can also be considered a "new building" in terms of the standards to be observed. And even if something basically already exists in terms of building volume, this does not necessarily mean that it is approvable. In villages, people are usually happy about every retained resident, but sometimes interim development plans impose restrictions. And what already stands as a barn is not necessarily allowed to be a residential building at that location. An architect therefore has a lot to "investigate" initially.

First, it should be checked whether the BV is even permissible in terms of planning and building law. Furthermore, it is a change of use requiring a building permit. The entire project processing is not possible without an architect/structural engineer, etc. Without clarification of the legal permissibility, for example through exploratory discussions with the building authorities or a preliminary building request, further questions regarding structural development or building insulation are premature. Generally, such a barn conversion is significantly more expensive than a new building of comparable size. One of the recurring problems is always the lack of foundation for the barn. You will not get around sufficient building insulation according to the Energy Saving Ordinance. Sand-lime brick inside and outside will therefore not work. The other mentioned points, e.g. exterior wall on a hillside, are demanding structural and building physics issues that a specialist planner must solve. Before construction execution and not afterwards, as damage limitation