In Berlin “new building offering affordable rental space” is a contradiction in itself: Building costs and land price of B-class locations lead to a price of 14-17 €/m² with 1,5 % interest rates, 2,5 % redemption rate, 1,5 % vacancy, management costs etc. taken into account. Yet, a rent between 6,50€ and 7,50 €/m² is being expected.

A more honest name for this would be “subsidized rental space”.

Many development plan procedures are stopped after a few years, others take several years although the demand for new residences is extremely urgent! This needs to be changed!

The urban planning tool “Rental Costs Checker” that we designed in collaboration with Dennis Müller, University of Applied Sciences Berlin, as part of a bachelor thesis explains the correlations between urban planning and non-subsidised rental rate in a clear and easy-to-understand way that creates transparency.

It compares urban planning designs in terms of cost efficiency and rents and thereby allows a non-professionals to understand how their doing in the participation processes will influence the end result:

“Where do you want your children to live when they’ve grown up?”

“Preferably close to me.”

“Well, then we have to ensure that our decisions within the participation process will make living in this area affordable for them.”

The Rental Costs Checker shows participants how immense the difference in rent can be between three floor detached houses and a seven floor perimeter block development as in Prenzlauer Berg with a commercial use of the ground floor.

When comparing a three floor and a seven floor building, several things become clear. Both of them incorporate a roof, a foundation. A building 9 m deep and 15 m wide needs a façade on the front and the back. However, where a detached building needs two insulated facades to the sides as well, a house in a perimeter block development does not.

The “tool” separates the building structure into different building components. The resulting building costs are the basis for a sustainable rent calculation (a rent that covers interest, redemption, management costs etc. – without profit/yield). Thereby, designs that make economically sense can be more easily identified.

When these results are incorporated into “honest participation processes” and it is explained how the number of floors and density can have a direct impact on the rent, urban planning can be designed in a way that living areas will be affordable for future generations as well.

To aid in this task we recommend the handbook “Certification for sustainable buildings – Avoiding cost traps via cost transparency” (German: Zertifizierung für Nachhaltige Gebäude – Vermeidung von Kostenfallen durch Kostentransparenz), available at the publishing house Dr. Köster, Berlin.