Spaceloft my only option?
Needing to get all the R value I can get in a limited space. From the cob webs you can see that this is an old house. Recently installed Cedar shakes with felt underneath over the 2×4 studs or mini rafters…
I think they call this a skip sheathing install of the cedar roof?
So, 3.5″ is all we have but we’d like to get to an R50 or thereabouts in our upgrade of this 1925 built home in Climate zone 4C.
Spaceloft seems the only option. With an R10 per inch. It comes in 10 cm thickness, 0.4″.
3.5 / 0.4 means close to 9 layers will fit in the 3.5 inch cavity. Plus one or two layers over top of the 2×4 rafters would get me to the R50 range.
The cost is exorbitant as far as I can see.
Cutting off the staple ends, putting up an airbarrier, going around the rafters following the roof under layment.
Housewrap is more a water resistant barrier than an air barrier I understand…
SO when installing this ultra expensive permeable Spaceloft what material is best to use to have it in an air tight, vapor open, cavity?
And than in 25 years when a new cedar roof goes on: better use short staples…
So in all: please advise alternatives to the “no other alternative?” Spaceloft…