ᐅ Building a house with two or three residential units?

Hello,

Thank you for the individual feedback on whether it is "worth it," but the question was...

"I am currently concerned about the additional costs due to stricter regulations for a house with three residential units (multi-family house).

Does anyone in this forum have experience with this? Is the extra effort and expense worthwhile?"

Since I do not have any costs yet, I wanted to ask here in the forum if anyone has information on this. For example, if the construction cost for a two-family house is around 3000 EUR/sqm (3000 EUR/sq m) and due to the additional costs for a three-family house this “advantage” of the third unit causes the construction cost to increase to around 3500 EUR/sqm (3500 EUR/sq m), then the two-family house would be preferable. This difference is what interests me.

If there is no answer here in the forum, that’s no problem—I will wait for the first meetings with the planners and so on.

Thank you

MFH2026 schrieb:

And this difference is interesting to me.

It depends on whether there are any specific requirements to be considered in the local building code or the development plan. Basically, the costs are roughly the same.

Thank you for the feedback.

The plot falls under Section 34, and the regional building code requires, at least in my understanding, an accessible apartment. However, I believe the planners will advise me on this.

The topic is really fascinating...

I completed a duplex this year. I’m renting it out for 13€/sqm (13€/sq ft) net rent. Maybe 14€/sqm (14€/sq ft) would have been possible, but not much more. The official land value is just under 300 €/sqm (300 €/sq ft).

For me, it’s already worthwhile, or I get a reasonable return. However, the return is only "good" because the construction involved a lot of personal work and contacts within the construction industry. There were also offers from general contractors for a turnkey project, which would have been significantly more expensive, and I would now need about 17-18 €/sqm (17-18 €/sq ft) to achieve a similar return. I don’t think the market would support that.

I only carried out the project because I already owned the land and, for family reasons, did not want to sell it.

From the third residential unit onwards, the building is classified at least as Building Class 3 (in North Rhine-Westphalia). This means that accessibility requirements according to §49 of the North Rhine-Westphalia State Building Code apply, as well as stricter fire protection standards. Additionally, besides the required engineering services, the corresponding expert inspectors must be commissioned, who are also obligated to document at least three site visits, including a final report (§68 State Building Code NW). It is important to carefully consider before upgrading to Building Class 3.

All other construction and planning law issues that need to be clarified in order to determine how much, where, and what can be built on your property must be handled by a commissioned architect on site, possibly through a preliminary building inquiry if §34 of the Building Code applies to your plot. Assumptions and quick advice from the internet are not a reliable basis.

wpic schrieb:

From the third residential unit onward, the building must be classified at least as Building Class 3 (in North Rhine-Westphalia). This means that accessibility requirements according to §49 of the North Rhine-Westphalia Building Code apply, along with higher fire protection standards. Additionally, besides the required engineering services, specialized inspection engineers must be commissioned, who are required to document at least three site visits, including a final report (§68 North Rhine-Westphalia Building Code). One should carefully consider before moving into Building Class 3.

Building Code NRW, §49
In addition to the accessible apartment, there must be a drying room and sufficient storage space for bicycles and similar items.
I also think of the parking space regulations or planning permission, which may specify two parking spaces per residential unit.
Maintaining privacy for each unit can also be challenging, as well as providing outdoor seating areas.
And finally: not every builder is suited for renting out units or acting as a landlord. It is not an easy job.