ᐅ New construction of an energy-efficient single-family house with a separate basement or in-law apartment

Hello everyone,

We are currently considering building a new single-family house (ideally a passive house, depending on costs) with a separate apartment with its own entrance door (for grandma). An alternative would be to renovate or convert our current house from the 1950s, but we expect that would involve much more effort and the costs would not be significantly lower.

Therefore, we are looking into an energy-efficient new build with a separate apartment. The house should be about 200 sqm (approximately 2,150 sq ft), with the apartment around 65 sqm (approximately 700 sq ft), though it could be smaller depending on the floor plan.

I wanted to ask if anyone has experience with new builds including a separate apartment and could possibly share tips for floor plan design. Maybe someone could also provide approximate costs (just for comparison) and any other important considerations?

The house will not have a basement and will be built in Regensburg.

Thank you in advance for your help!

Should the old house be demolished and then rebuilt?

The question is difficult to answer, similar to asking "how much does a car cost." An electric car would be a good option.

Take your time and compare demolition costs.

Choose a company that specializes in passive houses. It will be cheaper than a company that builds according to the energy saving regulations, and well, if necessary, a passive house is also an option.

Expect around 2,500 to 3,000 euros per square meter (about 230 to 280 USD per square foot), plus additional construction costs and demolition.

A floor plan without considering the plot is difficult. Have a look here and online. A single-family home with a granny flat is not uncommon. Check out "nullbarriere" as planning help for the granny flat.

It is important that you create a detailed room plan. For example, the bedroom with bed dimensions xyz. Distance from wall to edge of bed, linear meters of wardrobe, etc. Especially the features that might set you apart from others need to be included.

The old house will remain standing for now, as it is currently occupied. Sooner or later, it might be demolished. The new house is planned to be built next door. Has anyone had experience with construction companies regarding a granny flat / accessory dwelling unit?

icandoit schrieb:

Is the old house going to be demolished and rebuilt afterwards?

I. But my builder definitely isn’t going to Regensburg.

Any home construction company can build something like that for you.

Are you still allowed to build a house of that size on the plot?

Everyone includes a granny flat / accessory dwelling unit. There are no restrictions on the choice of builders for that.