The Thatched Roof is a slanted building-block looking like it's made of Reet that you can use as a roof-tile or for other purposes (it can be rotated).
It can be crafted in your Crafting Menu (default key "Q"), but only after the crafting-recipe has been unlocked by
- crafting a Processor
- crafting blocks of Thatched Walls after shredding tree Leaves in a Processor
- collecting Beeswax from treetops, grown from Queen Bees or found in Wood Treasure Chests a night
Crafting/taking a Thatched Roof is one of the unlocking requirements for the crafting recipe of Wood Roofs.
To craft 8 (blocks of) Thatched Roofs, you'll need:
- 2x Vines, taken from Cragwood-trees in Woodlands or Forests, from Wildwood-trees in the Jungle or obtained from several kinds of Leafies, either as a loot or pet-harvest
- 2 (blocks of) Shredded Leaves, made from any kind of uncorrupted tree Leaves in a Processor (which doesn't require any crafting recipes)
- 1x Beeswax, found on/within tree Leaves or rather often in Wood Treasure Chests at night, or can be grown from Queen Bees
Even though Thatched Walls are flammable under certain conditions (not in cold environments though), Thatched Roofs are fireproof.
Even when throwing Fire Bombs at Thatched Roofs, they still will not go up in flames.