Japanese to English Other Architecture

Context: 2階は、間口3間弱のトンネル状のワンルームとし、リビング・ダイニング・キッチンのどこからでも、北側に広がる街並みの眺望と反対側の森を楽しめるようにした

Scratching my head at this one. No idea. Also, the 弱 I assume is implying "roughly" or "approximately" but then again, how can there be "roughly" any amount of rooms or whatever in a house? There either is or there isn't a set amount, so I am so lost what this means here without sounding a little..well, ridiculous :)

Thanks.