Building a companion building instead

Now, how about just keeping the existing home as is - at least for now. And build another building 20 feet from the existing, 8 feet lower. In between the two buildings would be a pool and a patio.
This is actually very similar to the ideas I had when I first moved here, inspired by the MK Breeze house. The patio with the pool would be the breezeway. The existing home would be on the north side of the breezeway, the new on the south side.
I tried modeling it in Sketchup - sorry, it is very unpolished. Here is a snapshot of the houses seen from SSW.

Elevation sketches to go with the floorplan from June

I finally got the elevation sketches. They don't bring any surprises. Actually, they are very much like the model I made in SketchUp

Elevation sketch: North-facing side, as seen from the street


Elevation sketch: South-facing side, towards the meadow


Some questions:
- Judging from the shadows, it looks like the roof has been extended from the add-on BR across the entry area. I don't think that is much better than the current heavy overhang (only a foot higher up, and still making it into a very dark space.
- Actually, the pattern of shadows on the front could never appear; we are facing north and even in early morning the sun is coming from over the garage. The entry area is deep in shade for the rest of day
- It looks like one of the huge overhead doors (the crosses over 4 of the 8 windows in the "old box" on the south side) that Tom put into the Chicken Point cabin. It is an amazing structural element there? Here I wonder if it will look skimpy in my more modest setting - and I am also wondering if it is really practical: would I end up keeping it closed most all the time to keep out flying critters and the wind?

Questions for structural engineer

1. What would roughly be the requirements to foundation, posts and beams if I want to raise the ceiling of the "old box" 48", i.e. going to a finished-floor-to-ceiling height of 145", from currently 96 3/4" - the box is 16' wide and 48' log (outer measures), and the "top" would have several clerestory windows

Please note that I am assuming that the raised ceiling would be done by removing all roofing material (tar&gravel over 3-ply) "peeling" of existing decking and beams. I would be interested in reusing the beams and decking.

1a. However, does it seem possible and feasible to replace the current wood posts, beams, etc. with steel as I consider raising the roof and adding the new "top"? All the windows have to be replaces anyway. Would the steel be much heavier and therefore require even more extensive reinforcement of foundation?

2. The "old box" consists of 8 segments of each 72" width (defined by the beams); the middle 6 sections of the south facing side of the box would have large glass windows / doors. Would it be sufficient to put shear walls in each end, i.e. in each of the two outer sections?

3. Would requirements to foundation, shear walls, and posts be significantly different if -- instead of the above idea -- we replaced the current flat roof with one that is slanted upwards towards south, say, keeping the current height where the "old box" meets the add-on, and then raised to, say, 48" at the south wall. It would give the roof of the "old box" a slope of 4/16 = 25%

4. Would the garage roof be strong enough to hold an "extensive" green roof. According to some literature I found on the web, an extensive green roof weighs 12 lbs/sf (I believe that is to complete roofing surface weight)

5. Would the current roof of the "newer box" be able to carry solar panels, or would it require some structural reinforcement of beams, posts or foundation? It looks like solar panels would add a weight of 2.5 - 3 lbs/sf - in addition to the regular roofing surface which currently is tar&gravel.

6. Roughly, what kind of foundation would be needed if I wanted to add a room by bumping out 1/2 of the old box, say, adding a 144" x 288" room to the south side of the "old box"

7. Would I be able to add a new entry way as filling in the space between the garage and the add-on, simply by extending the slab on grade? Or would I need something more fancy as foundation?

8. What are the requirements to a foundation for integrating the 4' overhangs of the "newer box"? Would like crawlspace under the floor

questions for the town

Some of my big questions are:

1. would a complete re-roofing trigger the fire sprinkler requirement
The existing roof is a flat tar&gravel, with minimal insulation and directly on top of the 2" thick ceiling slats, i.e., there is no attic space. The roof would have to be completely rebuilt (not just resurfaced) if sprinklers have to be put in. Answer: No, not likely - if the entire remodels over a year are kept under $170K I should be fine.

2. If I rebuild the roof as a consequence of sprinkler ordinance but do not otherwise change the loads etc., would I also be required to bring foundation up to current standards? Answer: No, I would not have to beef up foundation in any part that is not the direct target of the remodel. I.e., people are not further penalized for doing work to comply with code.

3. If I go ahead and re-roof, would a re-roofing that also raises the roof over a 15.5' x 48' floor area (i.e., one of the 4 boxes that my house consists of ) trigger a requirement for ASCC review? I am attaching a model view of the existing appearance of the house from the street, as well as the appearance with a 4 foot extension of part of the roof. Answer: yes, a review is necessary. But it should be a no-brainer as they see this change as a very reasonable one. Though, brain or no-brain ;-) it will still take time. The next open slot in the ASCC schedule is in September!

4. Would installation of solar panels trigger a requirement to underground the electrical supply line from the pole at the street to the house? The house already has a 200A service panel that - according to some solar installers - is sufficient for whatever they need. No, "you are only required to do so when upgrading, relocating, or replacing a panel, or if you are building a new residence. Simply installing solar pv's does not trigger the undergrounding requirement"

Facts:
- foundation: 2235 sf (1680sf house; 545 sf garage) foundation w/ crawl space; garage is slab on grade
- framing: exposed structural beams (23' long, 4x10s, 6" oc), vertical support: 4x4 posts, 4' wide overhangs
- roof = ceiling: 2x8 center-match decking on top of structural beams; no attic
- roof surface (wide overhangs!): 3000sf (approx. )
- lot: 1.2 acre (approx. )

There are a number of given:
a. the roof is worn out; the entire roof need be resurfaced within the next 12 months.
b. I would like to get solar panels
c. I would like to replace single pane window glazing w/ low-e dbl. pane glass

basic structure

The structure throughout the house is exposed structural beams with the center-match decking on top, slats

Some of the slats in the decking are damaged by dry rot, and who knows what we will find when the tar and gravel is removed.

There are slight differences in dimensions: