so even though the walls & ceilings are not sheetrocked the attic is decked? interesting. normally, when insulating attic floor with foam the foam is sprayed against back side of the sheetrock ceilings. since your attic floor is decked, spraying against the decking from inside the hosue would be how you'd do it. so to do that..first the perimeter of the ceiling would be sealed. you want to seal the top plates, wire, pipe penetrations. then fill the ceiling joist bay with foam. to get the full depth of the joist you'd over fill the joist bay, then trim off excess prior to installing sheetrock ceiling. this would be option three. and the one I'd chose recommend. everyone...house is North Carolina. ducts in crawlspace, so equipment is either in closet inside living space, or in crawlspace. if the roof is high, and not used for ducts then it is more cost effective to seal & insulate attic floor. OP, check into what foam is used in your area. we use open cell in hot humid climates. are you sure the ceiling joists are 2x10? if so, that gives you 9.5" for insulation with open cell..that would be about R-36 depending upon R-value per inch of product. shop foam insulators wisely. you want a full joist bay fill, not an 'average' fill. what they mean by 'average' is that if you add up low spots & high spots of foam it 'averages' out to xxx. you want full depth everywhere. excess is cut off so that sheetrock install is smooth. ask to see jobs of the foam companies in progress. ask to talk to former customers. once completed..blower door test the install to make sure it has stopped air movement between attic space above into living space below. I gotta ask....why floor the attic so early in process? and where are heating system & water heaters? tell us locations, what size & what fuel type please. how will attic above foamed floor of attic be vented? do you have recessed lights? what provision has been made for recessed lights & insulation plan? are recessed lights Insulation Contact Air Tight ICAT?? knowing the answers to these questions may change answers to previous questions. best of luck

The coolers work awesome except some foams and caulks eat styrofoam so some testing needs to take place before you head into the attic. If you have to deal with codes and an inspector ask his opinion first. There are covers available that can be caulked in place and are treated so they won't burn and aren't quite as easy to find, are more of a pain to work with and to some are expensive if you have a dozen to do. One other option is a 'sealed' trim that goes on the inside. I think these are great if installed and caulked in place so they truly are sealed but then painting can be a challenge later. They come with a flakey stick on gasket which is still much better than a cheap trim but still is far from perfect without caulk. I have purchased the trims from Ebay much cheaper than home depot or lowes and I did use caulk and caulked the tiny slots in the top of the trim and at the ring to sheetrock contact area. Doing the rings inside the house still does not spare you from sealing the wires and pipes that enter into the attic which are huge leaks also. Most people blow off the recessed light sealing and they can be the largest hole into your attic and cause the most comfort/allergy issues. I have 14 and on an energy audit we tested the cfm or cubic feet per minute of air at each vent and register and also tested each recessed light on a day with light wind. I had an average leakage of 5 cfm from each light which doesn't seem like much until you do the math per hour and per day. 70cfm per minute for 14 lights 4,200 cfm per hour 100,800 cfm per day. I don't even remember the numbers when we fanned the doors but they went all over the place negative and positive which pulls nice clean air out of your attic and cellulose fibers or fiberglass fibers in for the owner to live in. I highly recommend paying someone to shoot your house inside and out with a thermal imaging camera before you jump in too far so you can develop a game plan. I also highly recommend a blower door test with the thermal camera and cfm testing ducts and such. I had less than 150cfm total of actual return air going through my registers on a 1200cfm system because I was sucking air out of the attic and basement for return air. I would have never known the severity of the issue without the test. Get the testing done and pay for it get photos of the results. I would pay for the testing and any other services I would wait on until you digest the information and figure the best way to attack the issues. I hope I get to read your findings and what approach you decide on. You are on track to keep money in your wallet and be more comfortable in the process.

When you speak of insulating in order use the attic as occupied living space, what parts of the walls, ceiling were you thinking of insulating? Insulating ceilings directly under roofs, as you may know, is problematic and requires special care. You can't just slap insulating material up under the roof sheathing. The attic/third floor insulation that is commonly recommended as the first step to weatherize a house is usually installed in the floor of the attic, blocking heat from escaping through the ceilings of the floor below. This is usually cited as the first, most energy efficent task that is done. Faced fiberglass batts between the joists are pretty easy to use here, but some people use blown-in cellulose within the joist acvities. If you have extra-deep joist cavities you can lay additional bats of fiberglass above the first ones. But if your plan is to insulate the side walls (if any) of the attic and the roof then you may want to consider foam, either as sheets or sprayed, and the special ribbed panels made by Owens Corning (among others) meant for installations in catherdral ceilings. These allow "contact" insulation against the roof while still maintaining an air channel above the insulation. What you should be looking for in this case is info about insulating so-called cathedral ceilings. A good first step, meaning fairly cheap, DIY, reversible and immediately effective on its own would be simply insulating the attic floor between the joists with fiberglass bats. Then as your heating plans firm up and your plans for using the third floor evolve you'll have something that you could remove and reuse (depending on what you have to do the fit the fiberglass batts in), and certainly someting that doesn't foreclose any future options, or interfere with wiring changes, new vents, etc. You asked about vapor barriers; although it would be ideal to have a vapor barrier install just above the ceiling interior finish in the second floor, it is often impossible. You can use careful fitting of faced insulation to help you in this case, and you can prime your ceilings with vapor retardant paint. From what I have read vapor barriers in ceilings are not as critical as vapor barriers in walls. I imagine this is because heat rises and even with insulation you will have some, perhaps adequate, vapor dispersion through the fiberglass and on out into the unheated attic. And hopefully, adequate (or at least no worse than you have now) dispersion through attic vents to the outside. Some of the issues of vapor barriers are related to how extreme your winters are. The colder they are, the more vapor issues intrude. FWIW, I am in northern NY (very cold) and I have faced fiberglass laid in parts of my attic with no other VB and nothing untoward has happened after nearly 20 years. Main issue is meticulously blocking entrance to the joist cavities so that mice and squirrels don't nest in it. Degrades it and makes it a bit stinky. Are you aware of the Preservation Briefs series of handbooks regarding care and maintenance of old buildings? I'll attach a link, there is one directed at weatherization and energy conservation issues that you may find very useful. HTH, Molly~ Here is a link that might be useful: National Park Service Preservation Briefs Series - A wide variety of topics useful to old house owners

http://www.southface.org/wp-content/uploads/2018/01/Georgia-energy-code-appendix-RA-AirsealingInsulation-keypoints.pdf page six foam sheathing to attic side of kneewalls (walls of living space shared with attic). don't skip detail #17 1. Question - the floor behind the kneewall is insulated with a loose insulation - does the ceiling need insulation behind the knee wall? no, your radiant barrier roof decking can not have materials installed against it as it will eliminate the radiant barrier. If so, I would run my vent all the way to the outside venting. If not, can I just run my air flow vent to the space behind the knee wall? vent (for bath fan? ) to exterior of house. never vent into attic. 2. Question 2 - I've seen both suggestions, do interior attic walls need insulated? the walls shared with living space and attic space should be insulated and air sealed with foam sheathing as detailed in linked doc 3. Question 3 - Several areas of large HVAC ducts - there is no room to insulate the areas, what needs to be done or can the be drywalled over, as the ducts themselves are insulated? where are these ducts located? I can't tell from pics. I see nice straight well strapped ducts in a joist bay. flex will either be R-6 or R-8, the latter preferred. not sure what code dictates for your location. best of luck