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Whats best way to insulate unvented attic room and room without vents

tolydj | Posted in General Questions on

first part.
Im building new house in douglasville georgia i think zone 7. or 3 . i have bonus room above garage with 10 x8  part of the room will be vaulted ceiling , ( rest of the room 16×8 is standard with regular ceiling.) the vaulted ceiling has 2×10 rafter 16″apart 10/12 pitch.  the vaulted part of the ceiling i plan to not vent and do closed cell spray foam, is that best way to go? i dont want condensation and i dont want to add on to reduce the ceiling height,  garage below will not be heated or cooled.
second part.
this house is 2 story so one room on the first floor has a lvl beam holding second floor wall. this room ceiling is 1/2 under the second floor and 1/2 shares the front porch roof with 4/12 pitch and a metal roof . how do i insulate this with no way of venting it beacause the second floor wall is right above it, also there is not much space in the ceiling for blow-in  insulation. should i block off the porch part of the ceiling away from the room and just do spray foam? closed or open cell?
.

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Replies

  1. GBA Editor
    Brian Pontolilo | | #1

    Hi tolydj,

    First, if you are in Georgia, you are definitely not in zone 7. You are in either zone 2 or 3 depending on where Douglasville is located in the state. Here's a map to help you figure that out: http://www.greenbuildingadvisor.com/article/climate-zone-map-including-canada.

    You can certainly go with unvented assemblies in these two roofs, just make sure that you are hitting the appropriate R-values with the right types of insulation. This article has all of the info you will need: http://www.greenbuildingadvisor.com/article/how-to-build-an-insulated-cathedral-ceiling

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