Translation:The attic is next to the storage room.
Does "attic" have a different meaning in Greece? Because where I come from, "attic" would refer to everything in a house above the "livable" areas. Which would mean that any storage room that was "next to" an attic would be part of the attic. Unless perhaps the house was built on/in a rather steep hill...
I would think a storage room can be near the attic if it is on the top floor, that is the floor directly under the attic. If I think about it, then I could definitely imagine this sentence meaning the storage room is near the opening to the attic (in the ceiling) if someone said this to me.