Proposal/Building units bedroom distribution

Building flats bedroom distribution
Proposal status:	Proposed (under way)
Proposed by:	Simgaymer
Tagging:	building=apartments, building:flats=*
Applies to:
Definition:	Structured extension of building:flats=* to describe the number of dwelling units (flats) in an apartment building by bedroom count.
Statistics:
Draft started:	2026-02-20
RFC start:	2026-02-20

Proposal

This proposal introduces structured keys to describe the distribution of dwelling units (flats) by bedroom count within apartment buildings.

The proposal extends the existing building:flats=* key by allowing mappers to record the number of flats with 0 bedrooms (studio), 1 bedroom, 2 bedrooms, etc.

Proposed keys:

• building:flats:0_bedrooms=*
• building:flats:1_bedroom=*
• building:flats:2_bedrooms=*
• building:flats:n_bedrooms=*

These tags are intended for use on areas or ways tagged:

• building=apartments

The values must be non-negative integers representing the count of flats of that bedroom type within the building.

Rationale

The existing building:flats=* tag provides only the total number of residential units in a building and does not describe their internal composition.

In many regions, official planning documents, development filings, and public records include breakdowns of units by bedroom count (e.g., studio, one-bedroom, two-bedroom). This information reflects the structural configuration of a building and may support housing stock analysis and typology mapping.

The proposed tagging:

• Extends an established key using existing colon namespacing conventions.
• Avoids compound string values that require parsing.
• Uses numeric bedroom counts to ensure international neutrality.
• Remains optional and backward-compatible.

The proposal is intentionally limited in scope to avoid feature creep and minimise overlap with market or occupancy data.

Tagging

Base Tag (Required)

The building must already be tagged:

• building=apartments
• building:flats=*

Bedroom Distribution Tags

Tag	Description
building:flats:0_bedrooms=*	Number of studio (0-bedroom) flats
building:flats:1_bedroom=*	Number of 1-bedroom flats
building:flats:2_bedrooms=*	Number of 2-bedroom flats
building:flats:n_bedrooms=*	Number of n-bedroom flats

Values must be non-negative integers.

Partial Information

If a complete breakdown is not known, only known values may be recorded. There is no requirement to map all bedroom categories.

When a complete breakdown is provided, the sum of all building:flats:*=* values (e.g., building:flats:0_bedrooms=*, building:flats:1_bedroom=*, etc.) should equal building:flats=*, if that tag is present. This consistency is recommended but not mandatory.

Not Intended For

• Individual apartment units mapped separately
• Single-family homes
• Rental prices, occupancy, tenure, or market data
• Internal floor area measurements

Examples

All Studio Building

building=apartments
building:flats=49
building:flats:0_bedrooms=49

Mixed Building

building=apartments
building:flats=25
building:flats:0_bedrooms=15
building:flats:1_bedroom=10

Larger Building

building=apartments
building:flats=120
building:flats:0_bedrooms=30
building:flats:1_bedroom=60
building:flats:2_bedrooms=30

Rendering

No specific rendering is proposed. These tags are intended for data analysis and specialised use rather than cartographic display.

Features/Pages affected

If approved, the following pages may require updates:

• building:flats=*
• =*
• Any documentation referencing residential flat counts

External discussions

(To be filled in after RFC announcement on the community forum and tagging mailing list.)

Comments

There must be at least two weeks set aside for comment before proceeding to a vote.

Please comment on the discussion page.

Revisions made to proposal

1. Keys changed from building:units=* to building:flats=* and all other associated keys in the proposal.
   Rationale: To conform with the keys used internationally per peer review.
2. Tag naming convention changed from building:flats:bedrooms:n=* to building:flats:n_bedrooms=* or building:flats:1_bedroom=*, the latter in keeping with proper grammar.
   Rationale": To remove the inconsistency with common tagging patterns after peer review.