Depending on the thickness you are talking about, you can either fir out the studs or use multiple layers of drywall. eg if the finished thickness needs to be 1 inch, you can use 1 layer of 3/8 and 1 layer of 5/8 and you get an inch. If it is much thicker than that, you would probably want to fir out with wood and then use 1 layer of drywall. You can cut wood to any width you want, so the options are endless. Either way, you will probably need to skim coat over the top to make it 100% smooth. Any hand made wall isn't going to be the exact same thickness at each point, but a decent drywall/plaster guy will be able to blend them to make them so that nobody will know the difference. Re Insulation - You may or may not be able to blow in insulation from the top. Before the invention of plywood sheathing, it was common to have diagonal bracing within the walls. To fill the wall cavity, you would likely have to drill additional holes to insulate below the cross bracing.

I won't comment about the engineering aspect, but have first hand experince dealing with house that has roofs over roofs. The old roofs were not removed, and trying to run wires or climb around in the attic can be a real chore. Removing the roof a section at a time once the new roof is up will only work if you plan on removing the ceiling and then dropping the chunks of the old roof into the room below, and that is still a pain in the behind. Our house started out as a 9x12 rectagle with a 12/9 roof pitch (yes more than 45degrees). Then another room was drug on to the property and the two attached. The second is 14x20 and had a 12/12 roof pitch. These two are T'd with the first section butting up to the side of the second section. THey were set about 6' apart and the first section was extended to meet the second section. Both of these are one level. Than a third section was built (1&1/2 story) that T'd off the second section. That section is 16x22 and has a 12/12 roof. The peak of the roof on the second section is about where the short wall ends on the second floor of the third section. This third section stuck out about 4' on the side where the first section was, and formed a small area between. THis was closed in and became a closet, and the roof was extended to cover it, but was flatten way out to match the eave lines. This part had extensive water damage from long ago. Then a porch was added to side of the first section, making it much wider. A new roof was built that extended from the original peak over the new section so now half the roof has a 12/9 pitch and the other side has a 3/12 picth. The old roof was left,including a layer of shakes and two layers of shingles. At some point this porch was closed in and turned into living space. Then a second porch was added off the second section, and the roof line was change to a 4/12 pitch. To keep the house from looking really strange, the roof line on the side connected to the first section was changed to a 4/12 pitch also, with the new roof going from the peak of the second section and extending out over the second roof of the first section. The small part over the second section that is on the other side of the peak of the first section was extended out to the end of the little square section between the first and third sections, that roof line has a different pitch than the other sides. That part of the roof had a swale and bounced becuase the people that did it made a big mistake. They cut the rafters so they were only 2" where they rested on the wall - we found that out when we removed the ceiling in that area. DH and I added an addition that T's off the other end of the first section. It is a few feet higher as we wanted a basement and have a high water table. We live in an area prone to tornadoes and really wanted a storm shelter - and I didn't like having to deal with an exterior entrance to deal with frozen water pipes in the small cellar the house had. We also built a cold roof over the existing 1 1/2 story section. That did not change the pitch but dealt with the poor insulation and ventelation problems. We also rewired and replumbed the entire house (it was not originally built with either, btw) and I spent a lot of time crawling around under the different roof lines. I had to cut out a decent sized section to gain access to some of the old wires (we vaulted one ceiling). That was a lot of work removing shingles with small tools (no room for a big shovel up there) and handing them down bucket by bucket through the small access panel in the laundry room. Only good thing is I was only a few feet from the access. Cathy

Clarification: When I said jigs and jogs /complicated footprint, I did mean the perimeter of the house; however, complicated wall layouts inside WILL increase your price as well. To keep your price reasonable, you want to "stack" your lower and upper walls so they're supported more economically. You say you're "learning the language of architecture" -- good! Because I've been reading this board and LOADS of books, I know ever so much more than I did two years ago! You'll get there too. All of us were wearing the short pants at one point. I MUCH prefer the dining room as a library, and I think BPathHome's inclusion of doors and bookcases is spot on. I also heartily approve BPath's sketch-up of the laundry room. It is EXACTLY what was in my mind. Except that I wouldn't care about the exterior door -- I despise hanging laundry, and I'd see the "hidden away" door in the laundry as something it'd be easy to leave unlocked. Yes, I'm planning to extend the porch on my house (because we're removing the little "indent" and replacing it with a kitchen booth. Pictures -- first the original: Then the updated -- note the simplified roofline (also known as a money-saver) and the longer porch: Giving credit where credit is due, I didn't draw this. MamaGoose did, but her concept and computer skills were perfect. As for the kitchen, if you're going to use the keeping room as your dining area (which I love), I don't think you need the French doors between the kitchen and the great room. I think they'd only be needed if you were having two sitting areas within earshot of one another. If you feel they're necessary, I'd suggest going with a set of double pocket doors (and you can pocket French doors) so that they can completely disappear when you don't want them. The only negative would be that you couldn't put nails in the "back walls" of the pantry, so you'd have to hang your family room artwork from up high (or, if it's small stuff, use command hooks). I'm not great at kitchen layouts, but I am strong on following a path. Think about how you'll move in the kitchen: You'll come in through the garage with groceries ... the pantries are right there where you enter the kitchen -- good; you don't have to walk across the kitchen, interrupting the cook, to put away groceries ... you set the groceries on the end of the island to separate them ... this makes the original island look better because it's closer to the pantries ... you want your refrigerator nearby too: ideally it'd be on the edge of your work space and near the pantry. When it's time to cook, you'll bring your food out of the pantry/fridge storage zone ... where do you set everything to prep it? Is the stove nearby? Where's your garbage? Where do you set your dirty pots and pans? Do you serve plates from the stove or set food on the table? Are your dishes stored in such a place that they're convenient to set on the table? And does all this happen without "backtracking"? Stare at your plan a while, and imagine yourself "going through the motions" of making a typical meal. This'll help you identify problem spots. I think I'd be tempted to shave off the bay window from the master bedroom. It does impede bed placement, and I personally am not into big, fancy master bedrooms.

If you're thinking of cutting it on the red line that's marked, don't, you'll be buying a new beam. At least in our jurisdiction anything done with engineered lumber, even when it's obviously stronger than 2x construction needs an engineers stamp on the plan and then needs to be built per the plan. Cutting on the red line would substantially weaken that beam, seems very unlikely that it's over-specified by that much. You're going to need a plan b in all likelihood.