My upcoming Project <Attic Build DIY> Video Added

I've been thinking about starting my HT Attic room for quite some time. My wife gave me the go ahead today. I have a large open space in my attic that I have been using for storage for a while. The size of my room is going to be 10 X 20 with 9ft ceilings. I could go 12 X 20 but I have a large roof support post coming down in the room. I was blessed that the flooring is already down (The builder said it was built with an addition in mind, and it shares the same 2X10 trusses as the upstairs bedroom does).
Do you think the building inspector will make me use the exterior wall and put a window in, or will I be able to build 4 new walls and not do the window. I am doing everything except HVAC, and electrical myself. Thankfully the upstairs already has its own AC unit and all they will have to do is run the vent tubes to the room (The AC unit is in the attic and will be about 12 feet from the room). I plan on doing this in 4 stages:

#1 Room Construction- Building room, insulation, drywall, lighting, and paint
#2 Electronics- Projector, Screen, Audio, Furniture
#3 Hallway walking to theatre
#4 Extra Storage

The Entrance

The Roof of the Attic (20+ ft high)

The Main part of where the room will be. Note the roof support truss coming down. I could go an extra 2 ft wide and build a column around the post, undecided on that.


UPDATE:
https://www.youtube.com/watch?v=XaFkSU1Rh9Y&feature=youtube_gdata_player
Attached is a video of the room I will be building in. It starts at 3:30 for the upstairs. Any creative ideas with the step up when you first walk in the attic? I can not change that as the downstairs hall has 12 ft ceilings and the rooms surrounding it have 10.
Edited by bduncan118 - 1/22/13 at 4:32am

That's a bummer for sure. You walk up the steps into a bedroom. Through the bedroom you go into the attic. There is a window in the bedroom. Unfortunately from the door to the attic to the door in the theatre will be a 12 ft hallway. I really didn't want to have to cut the exterior of the house to put the window in. That would be out of my comfort zone and something i would have to pay somebody to do.

This is on the second floor. Half the floor is finished the other half is the attic.

Thanks for the input! I most definitely wont be counting the space as a bedroom. The house already has 4. The current upstairs AC only runs about 200-300 sqft so i don't think it will have a problem with the new room. As far as the soundproofing Im not at all considering taking up the floor. I consider this a bonus that it is already down and i would be able to justify the noise downstairs to save the money. I will definitely look at the mat idea.

BD

Updates. I decided to go ahead with the window. Guy came out and measured and I should be getting an estimate today. The upstairs AC unit is 18,000 BTU (american standard Heritage 13) so I don't think adding another 275 sqft is out of the question. The existing room is a "T" room no more than 300 -400 sq ft. Below is the plan for the layout with a 3d image of it





The hallway came out a little mis-shaped but I'm ok with that. I actually ended up measuring 21ft long plus a 3 ft deep closet / AV rack room. There is a roof support beam that sticks out 3 ft into the closet area, so I will just leave that in the unfinished storage side to the right of the room. If the building inspector makes me hire an engineer to certify that the floor can handle the load I'm gonna see about moving the roof support over (Which will make the overall room 4 ft wider at 21X14).

I forgot to add that the entrance door will be at the top of the hump.