I am a great believer in that you don’t have to extend older properties in the same style as the original.
My catch phrase is “This [the existing house] maybe old but this [the extension] is new”
Let’s see how the master (and personal hero) Glenn Murcutt approaches this at the Pratt House (extension to Raheen) in Kew, Melbourne:
Here’s the old:
A large archiepiscopal palace built in 1884
And here’s an overhead view of the old plus the new extension:
The extension closes the U formed by the three existing wings in order to create an inner courtyard and is constructed in steel with tiers of laser cut glass canopies.
Although not all would love this contemporary extension to a period property it does show how a house can be extended in a contemporary manner.