ᐅ Urban Infill Development – What Are the Possibilities?

Hello everyone!

This is my first post in this forum, and I would like to join the discussion right away.

Last year, I happened to read about the "Minimum Impact House" in a magazine – a project focused on densifying urban areas by building a relatively affordable single-family home on a very small plot of land (about 30 sqm (320 sq ft)) in the middle of a large city (Frankfurt). The costs were approximately €40,000 for the land and around €240,000 for construction.

Recently, I also had the chance to spend a few weeks on vacation in Japan. In the cities there (especially Tokyo), space shortages are even more severe than in German big cities. As a result, they have started to use all available space as efficiently as possible. This has led to houses that are often only as wide as the garage on which they are built.

I am currently considering buying a property (an apartment). But here in Munich, where I live, there is a well-known severe shortage of affordable apartments.

It occurred to me that – at least in theory – it might just as well be possible to build a house on a minimal plot of land instead of buying an apartment, similar to the example in Frankfurt or the houses in Japan.

My question and topic for discussion are:
Urban infill – what is possible?

Some initial sub-questions related to this topic are:

• Is it even possible to find such a "mini plot" (e.g., 4 x 10 m (13 x 33 ft)) and obtain a building permit/planning permission for it?
• What architectural possibilities and restrictions do building codes allow for such a property?
• What challenges can be expected during such a project? (Aside from the usual home-building challenges)
• What cost range should one expect for such a project? (excluding the land)

I am looking forward to your opinions...

Best regards,
Hunderter

Regarding the "budget framework," some additional information:

-no basement
-4 floors
-100 sqm (1,076 sq ft) of living space
-average quality fittings
-timber construction

Four stories built with timber construction can be challenging. Each floor will have approximately 8–10m² (86–108 sq ft) of hallway space including the staircase, which also reduces the usable living area. The smaller the building, the higher the cost per square meter. Otherwise, you could check with the building authority to see if they still have any small plots of land available.

The problem with a plot of this size will be the planning regulations. Is it permitted to build on such a small plot? Factors like emergency access routes, utility connections, and similar aspects come into play.

If there is a development plan / zoning plan, its requirements must be followed, and this will hardly be feasible.

In Germany, such exceptions are rarely possible.

Best regards,
h. haass

Here is another example of making use of an infill plot:

In Kiel, there is reportedly the narrowest eco-friendly house in Europe. An architect utilized a gap between two buildings. While the front of the property measures about 4 meters (13 feet), the rear is only 80 cm (31 inches) wide.