Let the Framing Begin!
The exterior portion of the thermal envelope is pretty conventional. It is composed of a 2"x 8" stud wall at 24" o.c. This is as advanced as it gets. Although framers here have lots of conventional experience, there is little to no advanced framing experience in the residential construction industry. This is unfortunate since using less studs decreases cost and also saves energy and resources. The battle in my head on this has been won...and lost....Using my house as an experiment for OVE framing would probably expend more energy in headaches than the energy savings I would gain! I figure it is a win/loose....or loose/win situation which ever way you look at it. Seriously though, I took some time to analyze the R-values. The wall is composed of 1/2" spruce cladding, 3/4" air space, 3" of type I eps, 2x8 (24" o.c.) stud space filled with R31 fiberglass compressed to about R27, OSB, R15 fiberglass batt and gypsum wall board. The calculated R-value is about 49.88 according to this great little calculator: https://ekotrope.com/r-value-calculator/. Changing the exterior 2"x 8" stud wall to 16" o.c. emulates an increase in the stud fraction for a worst case scenario and gives an R-value of 48.95. The U-values for these assemblies are 0.0200 and 0.0203 respectively. Another way to look at this is that heat transfer has been reduced by 98% or 97.97% respectively. This illustrates a point. Adding a few studs here and there to keep your framer and the local officials happy is no big deal. It needs to make sense of course but adhering to local practices may not be the end of your energy efficient building. If window headers require double jacks then double jacks it is...If there are any questions you should contact your passive house consultant.
The walls on the main level are all 9' high. Since 2" x8" lumber is not a conventional wall building component, pre-cut lengths aren't available. This means that 10' lengths have to be cut down to the proper size. This leads to some wastage but since it's all kiln dried softwood it will make for great fuel in my Walltherm woodstove this coming winter. Its not a great use of lumber but at least it won't be thrown in the landfill.
Photo 1-1 shows the several of the wall sections framed on top of the concrete slab ready to be erected. Photo 2-1 and 2-2 shows a part of the West wall being erected. Photo 2-3 shows the west wall erected. This work is all done by brute force. It takes 4 workers to lift a section of wall and brace it. You can see the other wall sections in Photo 3-1 and 4-1. Note the size of that window opening. Its almost 9' across. I can see why triple glazed windows are so important in a structure like this. Achieving solar gains that outweigh heat loss would be a losing battle with a double glazed window.
Being in a windy location means the structure needs bracing, bracing, and more bracing. As usual it is another windy day (June 20th). Normally its windy. When the sun comes out, it's windier! The wind speed reached a sustained 50 km/hr yesterday. Today the weather is forecast to be sunny and 26 Celsius. The wind speed today is expected gust at 70 km/hr by 6 pm. Bracing the walls has been a bit of a challenge since there are not very many places to brace from. At this point keeping the slab free from that one load bearing wall makes sense from the point of view of the amount of space required to frame these large walls. Besides, the one hemlock beam that will be required to span the living area still hasn't arrived from Nova Scotia. It is not like we could move ahead with framing the second level until that beam arrives anyways. Until then the workers have enough to keep them busy; and me too!