diff --git a/README.md b/README.md
index fef85691c627181814cf6c080ec3851f5a00eb5e..c1bf7d2407fede1aab808872cb44067f7670ef46 100644
--- a/README.md
+++ b/README.md
@@ -57,17 +57,18 @@ Data-unit tiles result from the intersection of data units with zoom level 18 qu
 Consequently, the primary key of this table consists of four fields: `quadkey`,
 `aggregated_source_id`, `occupancy_case` and `data_unit_id`.
 
-| column name                       | data type     | description                                                           |
-|-----------------------------------|---------------|-----------------------------------------------------------------------|
-| quadkey                           | char(18)      | Zoom level 18 tile identifier.                                        |
-| aggregated_source_id              | smallint      | Identifier of the source of the aggregated model.                     |
-| occupancy_case                    | occupancycase | See [personalised enumerated types](#personalised-enumerated-types).  |
-| exposure_entity                   | char(3)       | Identifier of the exposure entity. If a country, ISO3 code.           |
-| data_unit_id                      | varchar       | Identifier of the data unit.                                          |
-| size_data_unit_tile_area          | float         | Area of the data-unit tile, in m2.                                    |
-| size_data_unit_tile_built_up_area | float         | Built-up area within the data-unit tile, in m2.                       |
-| fraction_data_unit_area           | float         | `size_data_unit_tile_area` / area of the data unit.                   |
-| fraction_data_unit_built_up_area  | float         | `size_data_unit_tile_built_up_area` / built-up area of the data unit. |
+| column name                       | data type     | description                                                                                                |
+|-----------------------------------|---------------|------------------------------------------------------------------------------------------------------------|
+| quadkey                           | char(18)      | Zoom level 18 tile identifier.                                                                             |
+| aggregated_source_id              | smallint      | Identifier of the source of the aggregated model.                                                          |
+| occupancy_case                    | occupancycase | See [personalised enumerated types](#personalised-enumerated-types).                                       |
+| exposure_entity                   | char(3)       | Identifier of the exposure entity. If a country, ISO3 code.                                                |
+| data_unit_id                      | varchar       | Identifier of the data unit.                                                                               |
+| size_data_unit_tile_area          | float         | Area of the data-unit tile, in m2.                                                                         |
+| size_data_unit_tile_built_up_area | float         | Built-up area within the data-unit tile, in m2.                                                            |
+| fraction_data_unit_area           | float         | `size_data_unit_tile_area` / area of the data unit.                                                        |
+| fraction_data_unit_built_up_area  | float         | `size_data_unit_tile_built_up_area` / built-up area of the data unit.                                      |
+| aggregated_buildings              | float         | Number of buildings from (`aggregated_source_id`, `occupancy_case`, `data_unit_id`) in the data-unit tile. |
 
 #### `data_units_buildings` - Information about buildings in a data unit
 
diff --git a/migrations/00008_add-field-to-data-unit-tiles.sql b/migrations/00008_add-field-to-data-unit-tiles.sql
new file mode 100644
index 0000000000000000000000000000000000000000..c64d0ea6b40f6d2cd0bdc9a537cb624e34126b64
--- /dev/null
+++ b/migrations/00008_add-field-to-data-unit-tiles.sql
@@ -0,0 +1 @@
+ALTER TABLE public.data_unit_tiles ADD COLUMN aggregated_buildings FLOAT;