I was considering adding more to it. Maybe when I get back into the game as it progresses but as it stands I think there's enough room to add the air filter extension into the corners of it between the stairways. Glad you liked it :)

No issues with stacking, very nicely done. Would be nice to get something similar with house extensions too. Thumbs up!

This is neat as one single blueprint but you can use designs with only 1 extension and 2 air seals, you're forced to separate the design in several blueprints though.

Nope it works on the roof too. Each house goes from 4 to 5 with the added extensions.

extention not work on the roof only when on side

BIG CITY