For about the last 20 days I've had a house requiring 19 Planks waiting to be built. I've had minimal other tasks to do, and over 20 planks for most of those days. And yet, the house, it remains unbuilt. I have tried adding another one, and await to see if the same thing happens.
Ah ok, well its a general issue, its also very strange you can't assign overseers to specific foraging/building/clear terrain tasks
I suspect whats happening is that the colonists will not move Planks from stockpile to building site until double the planks required are in stock I have just hit 40 odd planks and the colonists are now making the building.
Well the problem is actually that your stockpiles contain much less planks than shown in the inventory screen. You only have 3 planks in the stockpiles. So your inventory is wrong...i think @Nicholas wanted the game replays for such situations