Insulating an apartment cathedral ceiling built with 2x10s @ 2’6″ on center
I’m trying to build a “pretty good” little apartment – and I’m interested in recommendations on how to best insulate the ceiling – as noted , rafters are 15 ft long 2 x 10’s on 2′-6 ctrs., with existing tin roof and the usual rolled out insulation package under the tin. (supposedly R 4 but is smashed to R-0 betw tin roof and rafters) I’m planning to run perpendicular battens with thermal breaks to span the 2’6″ gaps of the sheetrock installation.
1) just stuff and fluff (2) 16″ wide R38 batts and retain w crossways battens
2) add another 2 x 10 between existing – this would be relatively easy.and gets me to readily available batts but adds another thermal bridge to insulate
3) blown spider glass: i’d think ideal but cannot find local installer.
Other details: 600 sf total floor area. This is actually a pole barn w raised floor on one end we’re building an apartment in. Walls are 2 x 6″ 16″ oc, and will be: installing thermal breaks under sheetrock, sealing all joints and doing blower door check. Floors 2 x 12’s w full depth insulation.
Cooling load handled w (2) small window units because of interior walls. Could not find mini split w less than 1.5 tons which would be way overcooled if i do my insulation and sealing right and is several multiples of window unit cost.
Heating solar thermal and outside air feed woodstove (if i can find one small enough)
Thanks for any help,
P.S. I forgot to write: the location is Climate Zone 3 in South Carolina.
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