I live in a 33 yr old, brick, 4br end-unit townhouse in Reston, Virginia (outside DC). In my opinion, this is a little bit of overkill in the bedroom department for a townhouse anyway. Coinciding with that thought is that my bathrooms are all pretty small. TH has two floors above ground, unfinished basement (to stay that way), gable roof with dead attic space. All the work discussed here would be on the second floor.
I am contemplating turning the smallest bedroom into a master bath including nice tile, large jetted tub, etc, and joining it to the master bedroom via new door. The ideal plan is to also extend the height of this bathroom up through the wasted space of the attic to the gable roof and put in skylights.
I have done some exploratory work (cutting drywall/subflooring) and I am sure the plumbing won't be a problem - plenty of space.
Target room is along the exterior wall of the house, between two load bearing walls that run perpendicular from the exterior wall. I am planning on making the adjacent 2x4 load bearing walls into 2x6 and doubling the number of joists where the jetted tub will reside (currently 16" OC, 12" in depth). The load bearing walls are supported by I-beams in the basement - about W8 or so - maybe 4" wide...
I know these questions are regional but from your own experience (site location please):
What permits are typically needed in this type of renovation? Can I submit plans of my own without the help of a Architect/PE? My background is AS in Architecture (can draw clear plans) and a BS in Mechanical Engineering but I am neither RA nor a PE.
Any experience/advice would greatly be appreciated.