A carved teak bench flatpack can be made at a workbench (Steel framed bench or better) in the Workshop of a Player-owned house. This requires 44 Construction, uses 4 teak planks, and gives 360 experience. The flatpack can then be used on a seating space hotspot in the Dining room or Throne room, while in building mode. This requires no Construction level and gives no experience.
The cost of making and selling a carved teak bench flatpack from scratch gives a profit of -1,446 coins.
After completing the hard Fremennik achievements, hey can also be traded to Advisor Ghrim in exchange for 225 coins being added to your kingdom's coffers in Miscellania. See Flatpack: Miscellania reselling for details.