But the law in this area is not all that easy to follow. You cannot copy the architect's artistic work, such as a drawing or plan, but he is not protected from others following ideas or concepts embodied in the plan. Copyright subsists not in ideas but in the form in which they are expressed. So, it is not an infringement of the copyright in the expression of an idea to take the idea and apply it, so long as that application does not involve copying the expression. Let's try to put it another way.
Many Victorian buildings copy details of classical buildings of Greece and Rome.
The difficulty is to identify the dividing line between the unprotected architectural idea and the expression of that idea in the form of a drawing or building which is capable of protection. Copyright will not protect the field of architecture from constantly evolving and developing. I can apply a new architectural idea and concept in my building and you are free to follow it as a concept. You cannot reproduce a substantial part of the original house where such reproduction comes about as a result of copying of the physical object itself. But the law does not restrict the application of architectural concepts and styles.