Just a Warning if u don't know already. I went to Chaengwattana this morning to extend my visa. I had an appointment so I drove there. Be warned..... most of the on street parking outside the building has been removed due to the massive ongoing construction. There is parking at levels 3 4 n 5 near the Centra Hotel but that was full. Took 30 minuts to find a space.
Leave Plenty of Time to park if you are driving to Chaengwattana over the next few months.