Hello! I have been a regular troller on this site for about three years now, and finally decided to take the plunge and hopefully benefit from some of the expertise on here.
Currently, I bought a new 1920's three story colonial (Philadelphia -approx. 2200 square ft) and have completely gutted the house down to the studs. There was an addition off the back of the house where the roof attaches to the house at about 13ft and slopes to about 8 ft to the support wall creating a vaulted ceiling. Naturally, while this is gutted, we want to expose the high ceilings. The biggest issue I have currently deepening the ceiling cavaties to obtain a minimum of R-30 (preferably higher) insulation. We will also have the same situation in the attic, which is ventilated. I do not currently have pics of what I am trying to describe but hope to be getting them shortly.
Short question to a long post: How do I deepen the ceiling cavities without "dropping" it to the 7.5 Ft they have now. Would the best idea be to fram a new celing say 13 ft and slope down to 7 ft in order to fit the insulation in?
THanks in advance for your responses. I am sure that I have many more posts in me with this renovation!
Depending upon the type of insulation you use, achieving an R-30 or, better yet, an R-38, is going to take a great deal of space. Your best bet, since they addition is so small, is to bite the bullet and have it spray foamed (2 lb, closed cell). Or, purchase some kits yourself (Tiger foam is one that comes to mind). A kit that covers 600 board feet (1" thick x 12" wide x 600' long) is about $650. One note though, you must have the room at the proper temperature to do this. I'm not that far from Philly and I can tell you it's way too cold to use spray foam in a room that isn't heated.
Another option, you could use rigid Iso insulation, 4" thick, which would give you an R-30 and then do a flash coat of spray foam to increase your R value, air-seal the space and have the room insulated so that you can bring it up to the proper temperature.