Let's eat our cake first, here's all the building types used in Red, Blue and Yellow:

Building Types in Gen 1 Pokémon

There are a lot less than I expected and as a friend said, "And yet it never feels too repetitive".

This post essentially a datasheet of the buildings used in Gen 1 by pointing out where they are and what they're used for. Then rounded out by looking at the tiles used to make the buildings and a couple of fun bits at the end.

Investigating Each Building

Here we'll look at each building from above, see where it is and what it is used for.

Location Purpose
Fuschia City Decorative Building
Location Purpose
Viridian City Pokémon academy, house
Pewter City House (3)
Lavender Town Lavender Volunteer Pokémon House, Name Rater's house, house
Fuchsia City House
Route 2 House
Route 8 Underground path entrance
Route 12 Fishing Guru's house
Route 16 House
Location Purpose
Cerulean City Decorative building (4)
Celadon City Decorative building
Location Purpose
Cerulean City House (3)
Location Purpose
Saffron City Decorative building (18)
Location Purpose
Pallet Town Player house, rival house
Saffron City Copycat's house, house
Fuchsia City Safari Zone Warden's house, Fishing Guru's house
Route 25 Bill's house
Location Purpose
Route 5 Daycare
Location Purpose
Pallet Town Professor Oak's lab
Location Purpose
Viridian City Gym
Pewter City Gym
Vermilion City Gym
Fuchsia City Gym
Saffron City Dojo
Cinnabar Island Gym
Location Purpose
Cerulean City Gym
Celadon City Gym
Saffron City Gym
Location Purpose
Vermilion City Decorative building (2)
Celadon City Decorative building (11)
Saffron City Decorative building (2)
Location Purpose
Cerulean City Bike shop
Vermilion City Fishing Guru's house, Pokémon Fanclub, house (2)
Celadon City Prize Exchange, Restaurant, Team Rocket office, hotel
Saffron City Mr Psychic's house
Route 2 Gate (2)
Route 5 Underground path entrance
Route 6 Underground path entrance
Route 7 Underground path entrance
Location Purpose
Viridian City Pokémon Centre
Pewter City Pokémon Centre
Cerulean City Pokémon Centre
Vermilion City Pokémon Centre
Lavender Town Pokémon Centre
Celadon City Pokémon Centre
Fuchsia City Pokémon Centre
Saffron City Pokémon Centre
Cinnabar Island Pokémon Centre
Route 4 Pokémon Centre
Route 10 Pokémon Centre
Location Purpose
Viridian City Poké Mart
Pewter City Poké Mart
Cerulean City Poké Mart
Vermilion City Poké Mart
Lavender Town Poké Mart
Fuchsia City Poké Mart
Saffron City Poké Mart
Cinnabar Island Poké Mart
Location Purpose
Route 7 Gate
Route 8 Gate
Route 15 Gate
Route 16 Gate
Location Purpose
Pewter City Pewter Museum of Science back entrance
Route 2 Gate
Location Purpose
Fuchsia City Safari Zone, Safari Zone offices
Location Purpose
Route 11 Gate
Location Purpose
Route 5 Gate
Location Purpose
Celadon City Decorative building
Saffron City Decorative building (5)
Location Purpose
Celadon City Decorative building
Route 18 Gate
Location Purpose
Celadon City Celadon Mansion
Route 6 Gate
Route 12 Gate
Location Purpose
Route 10 Power Plant
Location Purpose
Route 22 Pokémon League Reception Gate
Location Purpose
Saffron City Silph Co.
Location Purpose
Lavender Town Pokémon Tower
Location Purpose
Celadon City Poké Mart
Location Purpose
Pewter City Pewter Museum of Science

Building The Buildings

We'll look at two different building types that will cover most of the building tiles. First a look at the building, followed by an exploded view, followed by removing any duplicate tiles after the first tile, then reconstructing the building without those duplicates.  

Small House

As expected with a small building there's not too much tile reuse. Out of 32 tiles, we have 26 unique tiles. But we'd drop this down to 15 unique tiles if we used mirroring - everything right of the window in the reconstructed view would be implemented through mirroring.

Pokémon Centre

A slightly larger building with a different roof, a brick texture and a sign. Here we get 22/56 unique tiles. With mirroring we could remove the whole right side of the building leaving us with 18/56 unique tiles.

Shared Tiles

Below is the first image of this post and with looking at all the buildings at once, you'll notice that they share a lot. And we can group them by their roof and by their front face.

Roof:

  1. Curved rooves with a horizontal pattern
  2. Curved rooves with a cross pattern
  3. Flat rooves with a cross pattern

Front face:

  1. Windows
  2. Bricks
  3. Doors
  4. Decorative text

We can see this if we look at the 42 unique tiles used for buildings:

Adapted from work by FrenchOrange and Superjustinbros

While not all the space in this is used, it really shows the amount of tile reuse and sharing occurs to create all the buildings.

If we go back to the two buildings with exploded views and just took their shared tiles, we get a rough understanding of the base template of a building a player can walk into.

For every building the bottom tiles are nearly the same. Maybe some will have doors and maybe some will have signs but otherwise they're essentially the same. Similarly, every building has at least two windows.

Having the same bottom row of tiles, at least two windows and a choice of one three roofing options, it ends up being a matter of filling up the rest of the space with one or more of the main front face options and the size of the building.

A Unique Roof

Both the Pokémon Tower and the Pewter Museum of Science have a fourth roof type with a horizontal line through the middle:

This is the most front part (or from our perspective, the bottom) of the roof repeated again in the middle:

A Unique Front Decoration

One more differentiator, and it comes from our two-story-doored-building where there is a well defined horizontal line between the ground and top floor. Turns out, it's a similar trick to above, where the front roof tile is reused!

Game Boy Limitations

It takes 360 tiles to fill a Game Boy screen, but there is only enough VRAM for 256 unique tiles. Thankfully with how the Game Boy is designed, once we load a tile in VRAM we can use it any number of times for free.

With the building tileset of 42, we can build any building, any number of buildings with just 16% of the VRAM. Leaving lots of space for the rest of the tiles to create the scene.

Bonus 1

There's actually another building, and I found this while I was doing a playthrough of Blue to make sure I had my facts straight.

And we find this in the Safari Zone as rest houses or the Secret House.

Bonus 2

A cheeky quick playthrough over a couple of days. Excessive speed used.

Conclusion

Looking at the use cases for each building we find they're mostly concrete (excuse the pun), but every now and again, a design might be repurposed. A building that looks like someone's house could be a passage to the underground path, an office building can also be a gate or a gate could take the same shape as the back entrance to the Pewter museum. I.E. there occasional reuse for a different purpose.

We also can pad cities with doorless buildings as decoration and add personality to the city with varying building heights. Even building widths can come into play here such as Silph Co. or the double-sign gyms.

42 tiles are what is needed to create all the above buildings in the original Pokémon games. There is a lot of clever reuse in less important bits such as the base of the building or where windows are placed to break up the monotony. The original art designers could use these tools to scale up or down the size of a building and keep it within hardware limitations.