I want to extend bedroom over front porch any thoughts?

[miger]

I may need to extend the front small bedroom over my front porch. Here is a picture of two similar houses close to me where one has been extended.

Any ideas on planning etc and costs? i think looking at one on the right,at most it's a few inches forward of the front of the house.
Would it be a relatively straight forward job to complete?

Any ideas thoughts welcome