As of June 2019, the requirements of this achievement have changed.
The original requirements were 'Breach a Floor or Ceiling in "House" on Casual/Ranked Multiplayer or Terrorist Hunt'.
Now you can only achieve this in multiplayer, but on any map
instead of only 'House'.
Simply find a square breach area on a floor and use a breach charge on it. As per below, there are at least 3 on the map 'House'. ISSUES UNLOCKING OCT 2019:
A few people are having issues unlocking this recently. SCOTTLAND1986 was able to unlock it in Ranked match, Kafe Dostoyevsky map, breaching from 3rd floor to 2nd floor. Please try this map if you are having trouble with this. Original Guide:
You can do this quickly and easily by yourself in Terrorist Hunt.
on the main menu and click 'Options' and then into 'Multiplayer Preferences'.
Scroll down to the Terrorist Hunt game modes. Turn them all off except 'Terrorist hunt classic'. Then below that, turn off every terrorist hunt map except 'House'. Press
to apply the changes.
Go back to the menu and into Terrorist Hunt. Click
and make sure 'Lone Wolf' is selected.
Start the game and make sure your character has breaching charges equipped.
Finally, you need to find a room in the house with a square area on the floor, this shows a place you can breach. I found at least 3 on this map. 1 in the Master Bedroom (2nd floor), 1 at the top of the main stairs in the landing area (2nd floor), and 1 beside the pool/billiards table (1st floor). There may be others too but I didn't find them.
If you are having trouble getting to the room due to enemies or you just cant find the right place, send in one of your remote drone devices and roam around the house til you find one in a room that's free of enemies.
Once you are there, place your breach charge on the square area and detonate it.
Achievement should unlock a few seconds later.