[jpm6621]

I'm installing insulation in well what i call the attic but it's a side room next to the heated living space with minimal room because of the slope of the roof. First thing, this house has no soffit so i'm not sure how the roof has air flow like it should. It just has two gable end vents which arn't above this room and nothing at the ridge. I've been installing faced batt insulation in the floor of this space but i won't be able to staple it since it needs to face down towards the heated space, which is a kitchen and living room that's allready finished with sheetrock. If i just place the insulation between the joists, paper facing down, without stapling, doesn't this defeat the purpose of a vapor barrier since it will have gaps and not be sealed? Same thing with the walls of this space, i have access to the backside of the wall (inside this room), since its finished sheetrock i'll be able to place the insulation between the studs on the backside of the finished sheetrock, paper facing heated space, but won't be able to staple it. Years ago there was insulation in the rafters so someone must have heated this space, but i don't need it heated but need to insulate from the other heated spaces of the house. I live in NY if that matters. Any help with this would be great.

 

[joecaption]

If this is just empty space then the only vaper barrier you need is the first layer againt the ceiling. Any added area should just be unfaced.
Before doing anything you really need to air sela the whole attic. That means sealing up any place where lights or fans go through the ceiling and and plumbing and wiring holes with spray foam.
http://www.energystar.gov/index.cfm?c=home_sealing.hm_improvement_insulation_table

 

[jpm6621]

Ya i understand the only vapor barrier i need is the first lawyer, but you usually have exposed floor joists and studs prior to sheetrock, where you staple the paper to the floor joists and studs from the heated space and thats something i won't be able to do since the sheetrock is up and finished, so i'm working from this cold area from the backside, and this faced insulation will be sitting in between joists and studs and placed up against the sheetrock, but not stapled.

 

[Gary in WA]

You'll be fine; https://docs.google.com/viewer?a=v&...0pf2_7&sig=AHIEtbQylPzdnxaB0Oqk9yRrrdP1VBztDg

Gary

 

[HomeSealed]

+1, good advice above. Install the batting in the wall and floor cavities as you plan on. Before you do, air seal any penetrations with caulk or foam. In addition to the single layer of batting, it would be best to add another unfaced layer run horizontally. On the floor area you can just roll it out, on the wall tack it up and then cover with housewrap which you can then staple.

 

[jpm6621]

Well i won't be running unfaced batt insulation perpendicular over top of the floor joist since we store things in this room and i put plywood down. I know it's not much insulation or much of an r value but it's better than before which was nothing. The walls i actually did a few years ago but i definately installed it the wrong way, installed it with the paper facing towards the cold and then sheetrocked over it so i might be pulling down all that sheetrock and flipping the insulation around if it's going to be a problem, any input on that would be great. Is it worth it to change the way i faced the vapor barrier or will it be fine.