Floor area ratio/plot ratio, nationwide in Germany? Local building commission, official site plan

I have not yet understood how the plot ratio (Grundflächenzahl) and floor space index (Geschossflächenzahl) work and how much I can build on my property.

Status:
I own a plot of land in a purely residential area (WR) in a district in Munich with garden city character.
I have not yet ordered the official site plan, as I am just in the early planning days.

Question 1: In the official site plan, I should find the plot ratio and floor space index, right?
Question 2: Are the floor space index and plot ratio uniform throughout Germany for purely residential areas at 1.2 and 0.4 respectively?
Question 3: In newspaper articles, I have read that building projects with plot ratio/floor space index values of 0.x have already been approved in my area. Does this mean these values are only guideline values and what is approved/litigated can be built?
Question 4: If a distant neighbor was allowed to build with very high plot ratio/floor space index, can I refer to this and demand the same rights?
Question 5: If the floor space index/plot ratio is rather variable, how do I find out these values? Call the local building commission? Compare online properties with floor space index/plot ratio data on immoxyz.de? Or would my not yet hired architect know this from experience?

Hello,

I still haven't understood how the floor area ratio (Grundflächenzahl) and the floor space index (Geschossflächenzahl) work and how much I can build on my property.

Floor area ratio means ground plan and area ratio – floor space index floor space index.

The floor area ratio indicates how many sqm of ground area per sqm of property area may be built. The floor space index, on the other hand, specifies how many sqm of floor space per sqm of property area may be built. This includes the floor space of all full floors of the building.

Question 1: I should find the floor area ratio and floor space index in the official site plan, right?

No, in the development plan for the property.

Question 2: Are the floor space index and floor area ratio standardized nationwide for pure residential areas at 1.2 and 0.4 respectively?

No, they often vary even within a single development area.

Question 3: I read in newspaper articles that construction projects in my area have been approved with floor area ratio/floor space index values of 0.x. Does this mean these values are only guidelines and whatever is approved/fought through court can be built?

No.

Question 4: If a distant neighbor was somehow allowed to build with very high floor area ratio/floor space index, can I refer to that and claim the same rights?

No.

Question 5: If floor space index/floor area ratio is rather variable, how can I find out the values? Call the local building commission? Compare properties with floor space index/floor area ratio data online at immoxyz.de? Or would my yet-to-exist architect know from experience?

The property office responsible for you or the building planning office knows these exactly.

Rheinische greetings

Thank you, then I will start looking for the development plan!

If it is a current construction area with an associated homepage, the development plan is usually even available there

Since it sounds more like an existing property, there will probably be no development plan. Then §34a of the Building Code applies. In other words: you are allowed to build like your neighbors. In new residential areas, the floor plan or floor area ratio is often given as absolute values. For example, floor plan = 90 and floor area ratio = 150. This regulates that all houses are at most the same size, even if one has more land and the other less.

Hello Municheast,

if you just want to roughly plan a little for yourself, an excerpt from a map is enough. But if you – as I read it – want to get the last centimeter out, it is advisable to contact a planner/architect early on (that is, immediately). They can answer all your questions here in 2 minutes and can also tell you whether it makes sense to obtain the official site plan or the DXF file now.

The problem with the official site plan is that in M it is "only" valid for 1 year or must be kept up to date within this period until the final building application. Checking this is the task of the planner/architect. In addition, there are plenty of framework conditions that can influence the actual utilization of the maximum floor area ratio and floor space index, as well as an "local factor" regarding the assessment of these numbers. So if you want concrete numbers regarding the house size and height, there is no way around the planner/architect.

Best regards
Dirk Grafe