Fallout Shelter
19 Achievements
Vault-Tec Engineer
Build 50 rooms
25.25%
How to unlock the Vault-Tec Engineer achievement in Fallout Shelter - Definitive Guide
It must be done under the same vault (savefile).
And make sure it's the only room on your screen, because when you build the second room, the price will increase. For example the first power generator is $100, and the second will be $125, the third will be $150, and so on. If you keep destroying it, it will always be the first room and not cost you more money.
If you need any additional information:
For this achievement, you simply have to build 50 rooms in your vault. You will get this achievement naturally as you play, but you can also just build and destroy the same room over and over until you get this achievement to unlock. If you do choose to go this route, the power generator, diner and water treatment plant are the cheapest to build at 100 caps each.
See Home Sweet Home for a list of every room and their price.
The Vault door and Elevators will not count for this trophy. You can destroy a room as soon as it's built and it will still count for this trophy. You will probably get this trophy naturally while playing the game but if you want to get it quickly, build some cheap rooms and destroy them until the trophy pops. The cheapest rooms cost 100 Caps so you will need a minimum of 5,000 Caps.