Our front door will be like yours, 6080 flanked by windows on either side. It hasn't happened yet, so I don't have pix to post. If your backyard patio doors are the only thing on that wall (no windows on that wall), then I'd definitely go big! I just noticed on our dining room doors to the back yard that it looks very small but it's a 6'8" tall set, not 8'. You should definitely go 3'6" x 2 for those doors. If you have windows on that wall, then I don't necessarily think you have to do it. I'd stick with interior doors that are 6'8" or 8' height. From what I've read here, it's quite difficult in many parts of the country to get standard 7' tall doors.

There are several aspects to what you propose. Adding external foam sheathing would allow you to increase your air infiltration control by an order of magnitude from what you presently are capable of. This could be accomplished by taping the seams of the sheathing or using a Tyvek/Typar type barrier as well. Fiberglass batts don't resist air washing/infiltration and this added control would increase their effectives as an insulation. Next, adding external sheathing would allow you to bring your home up to the minimum recommended levels for your area. The government has a neat zip code program to recommend insualtion levels within homes. (The recommended 2x4 wall insulation for my area is R-13 stud insulation (we used cellulose) with an R-5 (1") foam sheathing for an R-18 wall.) There should be no code issue with doing any of this. You need to be realistic, though, and look at what is cost effective. I'd suggest investing in a program called HVAC CALC, about $50 for a one-time home license, and do a heat loss/heat gain calculation on your present home. This way you could see where your heating/cooling dollars are actually going - walls, windows, ceiling, doors. Some have bad-mouthed this program, but I have used it on several homes and most recently on our new home and it came in dead-nuts the same as the programs the pro contractors had. I would guess it's going to be a toss up whether your walls or windows would be most cost effective to upgrade. As far as the actual cost of doing the upgrade to the walls, there are so many variables. How much/how thick a foam insulation to use. Extruded polystyrene or a higher peformance polyisocyanurate foam board? Can the existing siding be reused or will that have to be replaced? Hardiboard siding or vinyl? Hardiboard needs to be painted. Is this a DIY job or will this be contracted out? Finally, the Building Science Corp. website is full of useful information applicable to your situation. http://www.hvaccalc.com/ http://www.buildingscience.com/index_html Hope this helps! Here is a link that might be useful: Zip Code Insulation Program

As long as any structural elements aren't affected, should be straight forward. We always use a portable concrete cut-off saw w/ diamond blade. It has a 15" diamond blade and attachement for a garden hose. They also have a saw that looks exactly like a chain saw, but i've never used or seen one in our area. Most rental yards carry them and will get you through the majority of the opening leaving a little chip hammer work at the upper corners as well as at he base. Safety up! Here is a link that might be useful: concrete saws

It's a interesting question. ANSI standard 2765-2020 (Square Footage--Method for Calculating) provides a standard method for calculating square footage of residential structures. Following the standard, dimensions are taken to the outside of the finished material above grade and the outside of the foundation wall below grade. Using that method, I think you can make a case that adding exterior insulation increases the square footage. By way of illustration, consider two homes with the same interior dimensions: one constructed with 2 x 4 exterior walls and the other with 2 x 6 exterior walls. The home with the 2 x 6 exterior walls calculates out to be larger, although the usable interior dimensions are the same. It's amusing--and you'd need to read the standard to learn-- that a method for calculating square footage gives an option for metric units. Could it be that the folks who write ANSI standards have a sense of humor?