...a little more progress - We continue to focus on completing the shop area. The ceiling insulation is next. This is a pain for a number of reasons, but the first and foremost is the fact that the ceiling is just short of 10 feet above the concrete slab. This calls the expanding aluminum plank into service, stretched between 2 ladders. It goes slow, like most facets of this entire project. The engineered I-joists that frame the ceiling/2nd floor are 16" tall. At 16" on center, this creates a huge cavity. This is a blessing for hiding all the wiring and HVAC and mechanical stuff. It's a curse for insulation. Why? Well, my original plan was to just use R-25 (8" thick) and call it good. After sharing thoughts and making a few phone calls to respected builders and engineers, I find that leaving an open air space in a cavity like that is less than ideal when it will separate a heated space (the upstairs living space) from a cold space (the entire first level which is comprised of the shop, and the garage). Furthermore, some sort of vapor barrier or retarder should be used close to the warm side. This would ideally be installed, somehow attached to the underside of the subfloor....or use kraft faced insulation and push it all the way up to the top of the 16" deep cavity. First off, I hate that kraft faced junk on insulation. It's a questionably effective method of controlling vapor transmission. At least that's my opinion. So now I'm worried about how to create a vapor block when it dawns on me that we used that Advantech subflooring across the entire 2nd floor. I called Advantech and their tech people agree that it will provide a decent level of vapor retardation. It is just slightly less than the vapor transmission of (drum roll please)....the kraft facing on insulation. So the tech guy switches me to the next level, their staff engineer. It winds up that his expertise is thermal engineering, amongst other techy stuff. Anyway, he agrees that the Advantech subfloor should provide suitable vapor retardation and recommends that I use plastic right on top of the subfloor in any areas that are carpet and hardwoood/laminate. This is great news and pretty much cures my need for a vapor barrier at the warm side of this huge cavity. Whew.... - Next issue.... So, while I have this brainy thermal expert on the line, I describe the little twist that we plan; to live in the shop area for a little while, likely thru this entire coming winter. This will effectively reverse the entire plan by making the bottom side the warm area and the top side the cold area. This would normally dictate a vapor barrier at the bottom side of the ceiling cavity. He waves me off this idea for the obvious reason that it will create a trap for any vapor that might sneak into the cavitities. For the short amount of time that we plan to be living in that shop area, it is the lesser risk to use no vapor barrier in the shop ceiling. Besides, we use a dehumidifier in the shed where we are staying now. It will be used in the shop to help control any vapor during this "transition period". - OK, so that leaves the amount of insulation in those big 16" deep cavities. He has the same reaction as others that know...I really shouldn't leave an air space if I can avoid it. It's not a huge deal, but it will make a difference in performance to do my best to fill the cavity. Wow; what a pain. There is so much junk up there with the HVAC and wires and stuff, plus it's 10 feet overhead. We considered blowing it in. Well, blowing fiberglass is nowhere near as good as cellulose when it comes to finding and filling voids. OK, then let's look at cellulose. I call the factory and talk to their tech people. The cellulose actually has some moisture in it and they waved me off of a sealed cavity (which makes me wonder about blowing it into wall cavities...?) Anyway, I have gone full circle and wind up back at fiberglass batts. Moreover, we decide to just bite the bullet and stuff the entire 16" depth of the cavities. Oh yeah, there's more. Since we are going berserk with insulation, let's consider that most of the HVAC ductwork is fairly low in the cavity and would have very little insulation protecting it at the bottom side. So, we buy a few sheets of 1-1/2" formular foam insul-board and use spray foam along the edges to seal it in. Yeah, I'm nuts that way. - - Every bay that has some HVAC ductwork is protected with the R 7.5 foam on the bottom and the balance of the 16" deep bay is meticulously stuffed with custom cut and hand fitted fiberglass batts. Yeah, it took a long time, but in the end it is the ultimate cocoon. The other bays are just plain stuffed, working around all the wires. In the end, the shop ceiling is something like R 45. It's one of those things that cost very little (comparatively) and I'll never look back and wonder "what if". - - I should take a moment to admit that I did make a few really bad moves during this work. The aluminum plank that I lived on for the entire summer of 2010 during the exterior siding and trim installation was put to work on a much lower scale for this project. It was set about 4 feet above the concrete floor, stretched out between 2 ladders. I must admit that when I was 15 feet above the ground last year, I moved very slowly and calculated every step. Looking back, I am certain a higher power was watching over me cuz I got out alive. Now, at only 4 feet high, I am much less attentive. My bad. I fell....twice. Both times was the entire 4 feet, sideways down to the concrete floor. At 53 years old, I don't bounce like I used to. The first fall was the worst when the back of my head blasted the concrete and knocked me outfor a few seconds. Dski said the lump was the size of 1/2 a small egg, not to mention the bruises on my hip and elbows. I take a 30 min break, put some ice on my new egg, and hobble back up on the horse that just bucked me. The rest of the day went a little slower. The next day, I freakin' did it again. Worse than that, I landed on the same hip and elbow. This time I kept my head off the floor. I just don't get it...or maybe I do. - - When we came down to do this ceiling insulation, we came prepared for the next step. - - We managed to get a few sheets of the 5/8" firerock up before we called it a (long) weekend. - - Thank God for the drywall lift. I picked it up about 3 years ago...I think I got if off'a Ebay. When we crank one of those 5/8" thick sheets right up to the ceiling and just roll it around until it's just right, it pays for itself.
