Progress!

The geotechnical report arrived Monday morning. 31 pages and nothing very surprising, since report author Dave Williams warned me that a stormwater infiltration system (a rain garden) would be ruled out. We have a soil bearing capacity of 2,500 psf (meaning the soil can take more weight than the normal 2000 psf), and no groundwater was found in the 14' borings or on the 70' steep slope. That is, the site drains itself nicely.

A roof garden seems a very good idea--it is strategic from the point of view of a Green Stormwater Infrastructure (especially without the rain garden), it is a flat roof, which should be cheaper, and I think it would be a memorable buyer feature, even though its only about 600 SF. A roof garden needs some slope, perhaps 1/2" in 12" (2.39°) and some manufacturers recommend holding it back 12" from the edge. Wind erosion seems to be a concern, so I decided a 12" parapet on three sides would help. The problem with a wimpy slope is how it looks from the side, but the parapets are level.

A.11.4 - Gutters, very important for the GSI, are shown in blue

We always had the Modern-Between-Hip Roofs thing going, this is just a little more intense. Heading down the "flat roof with 30 PSF of saturated dirt on top" road, SIPs seemed like a good idea. There are standard thicknesses--6.5, 8.25, 10.25. The Trees Room needs 10.25" for R-48 insulation, and can easily span 10' between cross beams. It might be cheaper to use 8.25 and add 2" EPS under the roof garden.

No reason for overhangs where we have parapets--12" sheet metal cap, cement board siding, and awning windows.

Several vendors sell living roofs as a system with drainage mats, filter cloth, and roll-out vegetation. At least one sells vegetation "tiles." I imagine its expensive, but it could be phase two.

Finally, I realized that the curb appeal side is distinct from the backyard, where I can pretty much do as I please, including a more purist architectural approach.

Keeping it simple--fixed glass between exposed cross beams on the sides.

We might want a brise soleil off the south wall to provide shade in July:

November 14, Noon

July 25, Noon

The brise soleil could be simple wood or clear aluminum.

Also, it occurred to me that we can simply move the glass door in the breezeway to BR2 (right of the Trees Room in the solar study photos, above). It's a good quality door, and we have to replace the 72" window in that bedroom because it doesn't provide egress. It's big enough, but the operable side has you climbing out over the basement stairs. The other side of the glass door unit is operable, so we only have to solve the fact that you're 4' off the ground.