[Server Bug | Building | Modifying finished buildings
I think, this is a Server bug. If you finish your building (e.g. your building hut) and want to add a roof later, you are only allowed to add new blocks inside or above the designated building area. Each border field (inside) is not buildable, you rather receive an error that you are not allowed to do this. This occurs wether you are the owner or have the rights assigned by the owner using the deed.
It's easily reproducible. Simply finish a building and try to add something on top of it in the border area.
Client version: First Alpha, don't know which version this is.
for devs issue reported https://github.com/StrangeLoopGames/Eco/issues/413
If you restart your server it usually fixes it for a bit.