Plumbing
Chimney Cap Large Smoke
A metal weak block with 100 hit points.
Harvest drops
Iron× 3-5
Taken apart with a harvesting tool (axe, pickaxe, shovel), before perks and tool bonuses.
When it collapses
Falling, it leaves 
Scrap Metal Pile (75% of the time) where it lands.
Where to find (3 POIs)
Trader Bob, Trader Hugh, Trader Rekt.
Points of interest built with this block (any of its variants), the highest tiers first, from the game's prefab files.