Pine stairs. Beware of termites.
The item id for Stairs Pine in unturned is 317. You can use this ID with the commands below to spawn the item, give it to a player or buy it on a modded economy server.
Useable: Structure
Construct: Roof
Size_X: 2
Size_Y: 2
Size_Z: 0.45
Health: 550
Range: 8
Explosion: 19
Blueprints: 1
Blueprint_0_Type: Structure
Blueprint_0_Supplies: 1
Blueprint_0_Supply_0_ID: 41
Blueprint_0_Supply_0_Amount: 3
Blueprint_0_Build: 27
PlacementAudioClip: Sounds/WoodenPlacement.mp3
Has_Clip_Prefab: false