Whenever i build someting with decorations in it the carpenter always still makes extra of that decoration. Even tough i have enough of the decorations in my storage.
That is because in your options you have enabled the builds requesting items. There is no way for the game to know if you want to use the items already in your inventory or if you want new items (for example, to sell the old ones).
You can disable this option and then builds will not request items, you will have to manually order your carpenter.