Single-family house with a possible granny flat?

Hello dear forum community,

my wife (32), our son (8), and I (30) want to build a house with a granny flat. My parents would move into the granny flat.
We are currently looking for plots of land in the district of Neu-Ulm.
I know from some acquaintances who have recently built that they got their plots for about €260/sqm.
I will explain our situation in more detail because it is somewhat different from normal.
We currently live in a semi-detached house, which I bought in 2013 for €180,000. We will sell this year and move rent-free into my father-in-law’s apartment so that we can save equity (€1,500 per month) until we find a plot of land. We will rent out this apartment when we move into the house. However, I do not include this in the income. There was another apartment that my wife received from her grandmother, but it was sold (our equity + savings) because we only had trouble with antisocial tenants. We got the semi-detached house very cheaply at the time because the previous owner was in the middle of building a house in Magdeburg and ran out of money. We hired a real estate agent who estimates the semi-detached house at about €370,000. After deducting the prepayment penalty and paying off the remaining debt, we would have about €200,000 (equity) left.


So we have about €980 left per month after all calculable costs if I haven’t made any mistakes.

Equity:
€70,000 from the apartment sale
€30,000 saved - €30,000 car loans = €0
€1xx.xxx from what remains from the semi-detached house.
Debts:
Car loan 1: €300 monthly installment; the loan will be paid off from equity
Car loan 2: €179 monthly installment; the loan will be paid off from equity

Loan:
We assume that we will need about 36 months to buy the plot + house. We calculate €200,000 for the plot and €450,000 for the single-family house + granny flat. The costs would then amount to about €750,000 including a buffer. If I deduct our equity (€70,000 + €200,000 + 36 months * €1,500), a financing amount of €425,000 would still remain.

Have I now calculated the costs for the plot + house nicely, or is this about right?
The house should have 150-170 sqm + 60 sqm granny flat. No garage is planned. Possibly a carport or something like that.

I hope my post is understandable and I look forward to your answers.

Regards

MJK2012

Hello, I think you should build in buffers there. What are you currently saving with the income over [4.700€]? Rental income for the apartment would also come in?

Hello, I think you should build in buffers. What are you currently saving with an income over €4,700? Would rental income from the apartment also be coming in?

Currently, €650 is being saved. I would increase the savings rate to €1,500 after moving into the apartment because after building the house, the loan installment would be €1,300 + €400 for additional costs. You can get used to that. Yes, the apartment will be rented out by us. A 70 sqm apartment in our area goes for about €650 cold rent. The total amount of €750,000 includes a buffer of €650,000 x 1.15. Regards MKJ2012

Yes, you have nicely calculated it for yourself. 150 - 170m² + 60m² granny flat will cost you significantly more than the estimated 450,000€. For a total of 220m², I would assume around 550k. That will be tight with the salary, or rather impossible. Leave out the granny flat. I don't understand anyway why someone who has already had enough bad experience with renting would then plan a granny flat.

170m² for 3 people seems quite a lot to me. You should be able to manage with 120m² or, if more children are planned, with 140m². Then it should become a bit cheaper again.

I don't understand anyway why someone who has already had enough bad experience with renting would then plan a granny flat.

Because the parents are supposed to move in there. Even if I wouldn't wish such closeness with either my parents or parents-in-law, I still believe that the problems arising from that are not comparable to those with "difficult" tenants who are strangers. Given the age of the OP, one can also assume that the parents will live for a few more years.

Is the granny flat going to be rented to the parents? --> rental income
Are you getting rent for the father-in-law's apartment? --> rental income

Even if you don't count those 100%, the two rents would probably bring your monthly rate into a more realistic range for the 750k€ + X investment.