The item ID for Old thatch roof 26 is OLD_wood_roof
This is the spawn command to give yourself Old thatch roof 26 in Valheim normally without the level option.
Copy the command below and paste it into your Valheim game or server admin console to obtain.
This is the spawn command to give yourself Old thatch roof 26 in Valheim with the level option if applicable. Below is just an example with the item chosen. Some items do not have leveling.
Copy the command below and paste it into your Valheim game or server admin console to obtain.