Cultivation and renovation of the parental home - realistic?

Hello everyone,
We are currently seriously considering and planning to take over my parents' house (built in 2001) and to extend it with an addition for my parents.
We are very uncertain about many points:
- My parents are thinking about transferring the house to us as a gift. I have 2 siblings – both already own property, one sister directly next door in my mom’s parents' house. Both would waive their " Pflichtanteil" in the context of a transfer of the house. We would pay both, after agreement, 50k each.
- What financial costs should we expect for the addition? Development plans are available. The size of the addition would be about 80 sqm. The main house is 120 sqm, and we would like to carry out some renovation work there – windows, floors, etc. We have roughly budgeted 50k for this.

Regarding financing: We are considering a loan of 200k – 250k.
My partner and I both have full-time jobs and have about 4500€ available per month. So far, we pay 900€ warm rent and are managing very well.
No "cash" equity is available – we are still very young and have only been earning full-time for 1.5 years. However, we would do all the work ourselves except for the shell construction and heating.
No loans, etc., exist so far.
Is it “realistic” to proceed with more detailed planning under these conditions?
Thank you very much and best regards

How do you come to the conclusion that you can do that? Are you active in the trades? Without [EL, Auszahlung, Anbau Renovierung] one should plan at least 300, with a lot of [EL] you might be able to subtract 30-40, but it won't be less than 250.

2 x 50k to buy out the siblings + 50k renovation main house + 80sqm x 2,000€ extension = 310k budget requirement. Without buffer or any extras. How do you come to 200k - 250k loan amount if there is no equity?

2 x 50k to pay off the siblings + 50k renovation of main house + 80sqm x 2,000€ extension = 310k budget requirement. Without buffer or any extras. How do you come to 200k - 250k loan amount if there is no equity?

Sorry, we are assuming 300k - 350k - typo. We have some buffer, but less than 10k. Until the start of construction, we could probably save a bit more so that we could start the project with about 15k equity. I know, not much, but better than nothing.

Then it fits at first glance. Just get started on your project and see what comes out of it and whether you can/want to afford it. Try to plan as detailed as possible. Get quotes (for example for the existing house, which is also possible without contact due to Corona. Just measure the windows, send the dimensions to companies and request quotes). Also plan the kitchen at the kitchen studio when it is possible again. Bathroom furniture, sanitary facilities, lights. All this 'small stuff' makes a big difference but can actually be determined very well in advance. For the rough extension / shell construction, a company has to be involved... There you will get concrete quotes.

How do you come to think that you can do that? Are you working in the trades? Without EL, payout, extension renovation you should plan at least 300, with a lot of EL you can maybe deduct 30-40, but it won’t be less than 250.

My family and my boyfriend work in the trades – roofer, electrician, technician, etc. – and only recently completed my sister’s house – almost independently, except for the shell – They definitely know what kind of work it involves. And about the loan amount: We are assuming 300k – 350k, a small typo.