I often tell myself that starting a project is the hardest part. That is definitely true of our house build. Swimming in a sea of details through the winter and early spring had me wondering if we would ever be banging nails. We just finished digging our foundation hole and I am still wondering if we'll ever be banging nails! But we are immensely excited to have begun building our bigger house.
We love the Gypsy Wagon tiny house, but each day that Ella gets bigger our house gets smaller. At 1,100 sq ft, it will be half the size of an average american house (around 2300 sq ft). But it will give Ella plenty of room to run around. It will also give us space to have friends over for dinner in the colder months. From our experience living in a tiny house these are really the biggest shortcomings that living tiny has shown us. Other than that we have really loved living in the tiny house.
Our bigger house will be a simple cape style with one bedroom up under the rafters. This winter I spent many MANY hours reading articles on GreenBuildingAdvisor. This site has a plethora of information on energy efficient home design. This research greatly influenced the design. GBA helped convince me that high insulation values are a necessity in our climate. One article in particular titled The Pretty Good House really stuck a chord. Among other things, the PGH has R-40 walls and R-60 ceiling insulation levels. We are planning for our house to last at least 100 years (and for this reason choose not to use plywood which has been known to delaminate over time). When thinking of all of the BTUs needed to heat the house over that time frame, it makes sense to put extra energy into a well insulated shell now. Here is a rough sketch of it at the present moment.
It's not a yurt? There is still some sadness in Mike's heart because of this. The taper-wall yurt is the most beautiful structure we know of. Mike began designing a two story yurt. But as he read more about the simplicity, reliability, and freeness of passive solar design, the yurt began to morph. First was an attempt to stretch out the yurt into an oval. This yielded a design that too-closely resembled a circus tent. The next mode of thinking yielded what Mike called the "ovagon" (octagon stretched into an oval like shape).
an early nautilus like drawing
Many different shapes and configurations were considered...
We came to the conclusion that though we absolutely love the aesthetics of the taper wall yurt, functionally our priorities lay within a rectangle. Even though the foundation hole is already dug, some days Mike still thinks about changing the design to a yurt. The saving grace is the knowing that we will have the need for more small structures in the future - which will indubitably be some yurt-like incarnation.
Some specs on our new design:
Foundation: frost proof shallow foundation. It will be a monolithic slab very much like this one. A continuous layer of insulation beneath the concrete will reduce thermal loss (R-16 in our case). We will use Roxul Comfortboard 110 below the slab (with a 25psi EPS (Atlas ThermalStar X-Grade) below the footing since Roxul doesn't have the compressive strength to support the weight).
Walls: Local Rough cut 2x6 framing with dense packed cellulose. 4" of exterior Roxul Comfortboard 80 will be applied outside of the sheathing and WRB. This will give us a wall R-value of just about R-38). Outboad of the Roxul will be a vent channel followed by cedar sidewall shingles.
Roof framing: We thought about using trusses but their higher materials price combined with their poor fire performance led us to us a rafter design. We will use 2x12 rafters which will be furred down to give a thermal break as well as allow for 17" of dense-pack cellulose for an R-value of 60. We will install the WRB above the rafters, a vent channel, furring strips and finally corrugated metal roofing panels.
Windows - Our energy consultant (Efficiency Vermont offers free energy consulting to its residents - how cool!) Steve advises us to by the best windows we can afford. So, we are sold on getting triple paned Intus windows at least for all of our fixed windows. They have a very low U-value at a reasonable price (under $30/sf). However, Intus only makes tilt/turn windows which we are not really keen on. So we are still shopping around with Marvin, Andersen, Pella, etc. Because of budget restraints I think we will most likely get double paned windows for our operable ones. One challenge we have come across is that many window manufacturers don't offer windows for passive solar houses (glazing with a high solar heat gain coefficient or SHGC). We are still researching what will be best for us.
What's happening now? Last fall we bought a 1974 International 2400A tractor with loader/backhoe attachments. This has been a great asset to us and has moved some serious amounts of dirt. The piles are as big as a house - no joke. We just finished digging and hope to have our excavator deliver/spread/compact ¾" washed stone this week. Once that is in, we can start forming for the monolithic slab.
the first scoop...
just about done digging
We have the Roxul subslab insulation waiting to be laid and we just got a load of rough cut 2x6 hemlock framing lumber for our walls. I just finished making a new handle for my favorite hammer head and can't wait to start banging nails. It is really satisfying to see things coming together.