In terms of the addition of usable square footage, it's difficult to say. What I can tell you is that we are gaining an 8x8 bathroom on one end of the upstairs "hall" and a walk-in closet on the other end, and neither of those was possible before. We are actually raising the entire roof on that side of the house in addition to the dormers so we are also eliminating the knee wall in the bedrooms. I anticipate we'll gain quite a bit of usable space there as well. The scope of the project is pretty vast. In a nutshell we are taking the roof off the east side of the house and raising it, adding in the shed dormers, adding windows in the bedrooms in the shed dormer, adding the bathroom (which I would say is medium to upscale in terms of finishes as we're doing tile and a frameless glass shower), reshingling the entire roof, adding the deck and pergola and adding a sliding door to access the deck. The estimates we received ranged from $50,000 to $130,000. Once we got a little deeper into the inner workings of how our house is put together and what we need to do in terms of structure, it looks like we'll end up spending in the range of $85K. (Ick ... I've not typed that number before. That makes it a bit too real for my tastes). We also live in an area that seems to be on the higher end in terms of building expenses and I have no idea why. The roof, for instance, is not going to be anything special (30-year asphalt shingles) and accounts for about $18,000 of the budget. This is a project that started out of necessity. Existing dormers (you can see one peeking out in the existing house photo) were installed improperly and never insulated properly. After having insulation and roofing experts come out, we determined that the only way to really FIX the problem (which involves shoveling the roof when it snows, going up on a ladder to break up ice dams every time its done snowing and occasional leaking) was to remove the dormers all together. Of course we also needed to reshingle the roof. And as long as we're doing that .... and well, you know how it goes. Sort of takes on a life of its own.

I appreciate everyone response. They have give me some things to consider and look into. Normally here in northern vermont there is no need to get a permit unless you are changing the footprint of your home. However this is a new town for me and a dormer does add square footage. Connecting the 2x10s into the 2x8 ridge was a concern of mine as well. The information about the special type of joist hanger is very helpful. The second floor is already a living area so the floor joists should be fine, and the new dormer wall will go directly over the first floor wall. The ridge beam is unsupported over a span of 11 feet and then is supported by the wall between the bedroom and open loft area. I generally tend to over engineer these types of things. To be safe I am planning to put the 2x10 rafters 16" o.c. I am basically copying a dormer on my existing home, also in snowy norther VT. The real issue/concern is tying it back into the smaller framing on the other side. Any additional insight is appreciated. TIA Jack

Are you in Chicago? I only ask because this is a *thing* here and I just saw a local thread on it. The consensus is that flipping the stairs from the kitchen to dining room is about $10-12k, if you do it to code (almost certainly required if you want it to be marketable) Likely, the existing stairs are very far off from current code and when you make any alterations to them, you need to follow current code. Once you do the stairs, doing the dormer is a whole project as well. We have a required ratio of floor square footage to ceiling height needing to be 7'. Framing and finishing the space isn't necessarily the expensive part, but adding HVAC, windows, electric, etc... can add to it. All in, flipping our stairs, adding a back half dormer with 3/4 bathroom and finishing the other side of the attic was going to be $100k. We got the kids bunk beds. :D

We love our split level. We added a level over the main floor, and extended so its each level.is a nice size, but ita still a split, with 4 levels and a basement. It is so nice that all areas of the house are easily accessible and connected. Wherever family members are they never feel too far away, it's a very cohesive house plan, and at the same time there is separation so when pple are sleeping etc noise doesn't travel because the levels aren't directly on top of each other. I dont know why it's the 'least desirable', I think when done nicely it has a lot of great benefits. Obviously if stairs are difficult it isn't for you but for a many families it lives very well