Originally Posted by CDLehner
Yeah, this is what tripped me up from just rushing right in the first time; I read all this stuff about needing to ventilate, so you don't trap moisture in your ceiling and rot all the lumber...and about how if you face the reflective paper the wrong way, or use the wrong insulation type, you can melt the shingles on the outside roof.
As I've said, I don't know jack about home DIY, so this stuff I read scared me to death and that's why I'm trying to elicit any advice that I can. So where do these baffles go? Is it at the bottom of the "joist-channel", like where the insulation would come down to the knee-wall?
Install the baffles in every joist cavity the entire length of the joist. (I have seen some installers leave a 6-10" gap in between each baffle to save a little money and use fewer baffles.) Some people think the baffle is there to allow for ventilation for attic space, but in your type of application where you are filling the ceiling joists with insulation it is used to keep condensation and moisture from being trapped between the fiberglass batts and the roof decking. Insulating the roof would be quite easy, and you do not need to spend the extra money that an installer would charge you.
First step would be to staple install the baffles in your joist space. Some have self adhesive tape that you just peel and stick, others you staple into place. Start at the top of the ridge and work your way down. If you are only insulating to the knee wall, you only need to bring the baffles that far down. If you intend to insulate all the way to the exterior wall, then take the baffles all the way down to the base.
Next, push the batt insulation up into place, cut to fit with an utility knife, and staple the kraft paper face to the joists (paper faces the inside of the room and you would drywall against it.
It really is that easy. Just make sure you where long sleeves, gloves, a dust mask and eye protection because you don't want the fiberglass particles getting in your nose or eyes or on you because they irritate like all get out.
As for the HVAC, a zone to the HT would definitely make the space more comfortable and help control your heating and cooling costs since you could install a programable t-stat and ensure it is not runing to the room when it is not in use, but you need to weigh the cost vs. benefit. If the budget allows, I personally would do it, but if the budget is tight, you will be just fine without the separate zone.
I think a dedicated circuit is a must for a theater room. A good electrician can fish a main line down through the rest of the house with little or no damage to the finished areas of the house.
The floors wouldn't be MDF. Probably OSB which is a structural sheathing. Ideally it should be a minimum 3/4" for a floor, so if it is less than that, definitely add another layer. If keeping sound out of the rest of the house, and keeping outside sound out of the theater are your concern, then definitely add another layer of OSB with Green Glue between the layers.
I would get any HVAC and or electrical work done first, then tackle the insulation and subfloor, then move on to drywall, etc. If you want the riser isolated from the wall, install it after the drywall is complete.