ShareThisWe've just begun demo and construction on two Passive House projects in Sonoma, The Wood Residence. Owners Jennifer and James Wood are active environmentalists who wanted to build an "eco home" and in the course of their research, found out about a tour of our previous project, The O'Neill Passive House retrofit in Sonoma. After being "blown away" by what we had achieved, they decided to go with the same design and builder team and here we are. We are building both the guest house and main residence to the Passive House standard. Set on a very large lot in southeastern Sonoma, the existing home was not anything they wanted to keep, except the footprint. We just finished taking the house down to its foundation and sub floor (100 % of the old foundation and substructure have been incorporated into the new design) and have just poured the foundation on a guest house. Jarrod Denton, the architect, and I knew we had learned a lot on the first job and wanted to streamline the process of getting to that airtight envelope. On the O'Neill house we used a wall assembly based on the REMOTE/PERSIST method developed for colder climates. Sonoma is a very mild climate but with extreme temperature swings and periods of extremely heavy rain so this method was overkill. We are developing a new wall assembly that will simplify the process and also be more cost-effective. Some challenges include the existing raised floor cavity which is built with 2 x 8 floor joists leaving only a 7 1/2" cavity for insulation. We will use the blown in blanket system (BIBS). In contrast to the O'Neill house, we've taken the existing structure down to the floor so we're not limited by existing framing. We're currently planning to use Optiwin 2-Wood windows clad with aluminum to add durability taking into account the moisture variance during the seasons.