Wood extension
From Cantr II Wiki
A wood extension goes in a cottage or another wood extension and acts as a separate room, but doesn't cost as much or provide as much room as building another cottage inside would.
Construction
Object: Wood Extension
Days needed: 12
Raw materials needed: 7500 grams of wood
Objects: none
Tools needed: hammer
Capacity
People: 8
Weight: 1400000 grams