We considered recently to add a smallish sun room to our house - which was built about 60 years ago, plus renovations. Single family, rural - really no issues re: zoning, environmental, neighours ( none ), no easements, nada .....

We looked into the bureaucracy:
- Septic system inspection to ensure there was sufficient capacity in case someone "lived" in the sun room. 
- We are about 20ft. elevation above a small creek and pond. Would have had to get local conservation authority to inspect that we would not be flooded. The creek rises maybe 2 ft. during spring run-off.
- Plans and construction ( trivial ) would have had to undergo a complete building inspection, approval of plans, and ongoing construction supervision.
- The whole project would have had to go to "Toronto" to get a variance - I have no clue why.

At this point we gave up as the whole bureaucracy alone would have cost us more than the actual sun porch !!!