Hello,
I am finishing a room above my garage and am trying to figure out how to best insulate the cathedral ceiling. On one side of the room, the rood if pitched at at 45 degree angle and has soffit vents. On the other side of the room, there is a large dormer, and the area that isn't taken up by the dormer has the same 45 degree angle, but on this side, there are no soffit vents. Another complication is that the ceiling is only constructed with 2x8s instead of 2x10s or 12s so the standard R-30C or R-38C insulation with a baffle won't fit in the celing as is.
So, my question has a few parts. I live in Rhode Island so I would like at least R-30 insulation in the ceiling. My thought was that I would put in two layers of high density R-15 insulation in with the baffles. This way I could get the R-30 rating and still have room for the baffles against the roof. Would the two-vapor barriers cause any problems with moisture? My other option would be just to stuff R-30C in the space with a baffle and loose some of the R value due to compression. Also, on the side of the room with the dormer and no baffles, do I need to put in any baffles on this side since there are no vents on the bottom? Or could I just put in the R-30C insulation right to the roof? Thanks in advance for your help. Any insight to my conundrum would be really appreciated.
I am finishing a room above my garage and am trying to figure out how to best insulate the cathedral ceiling. On one side of the room, the rood if pitched at at 45 degree angle and has soffit vents. On the other side of the room, there is a large dormer, and the area that isn't taken up by the dormer has the same 45 degree angle, but on this side, there are no soffit vents. Another complication is that the ceiling is only constructed with 2x8s instead of 2x10s or 12s so the standard R-30C or R-38C insulation with a baffle won't fit in the celing as is.
So, my question has a few parts. I live in Rhode Island so I would like at least R-30 insulation in the ceiling. My thought was that I would put in two layers of high density R-15 insulation in with the baffles. This way I could get the R-30 rating and still have room for the baffles against the roof. Would the two-vapor barriers cause any problems with moisture? My other option would be just to stuff R-30C in the space with a baffle and loose some of the R value due to compression. Also, on the side of the room with the dormer and no baffles, do I need to put in any baffles on this side since there are no vents on the bottom? Or could I just put in the R-30C insulation right to the roof? Thanks in advance for your help. Any insight to my conundrum would be really appreciated.