The straw bale component of the home (the bedrooms) has finally been taking shape. None of the straw bale walls are load-bearing which greatly simplifies the process. To see the floor plan which identifies these thick walls in relation to the overall layout, click here. The past session was spent framing the curb rails (sills) and box beams at all vertical corners, window and door jambs as well as stacking bales. Diverting from the traditional top plate, which can also be framed similarly to the vertical box beams, we have chosen to incorporate the 7′-0″ high band of cedar, aka ‘the datum’, as our top plate framing. This installation will happen in the beginning of the next session so it will be absent from the following photos. 

curb rail and vertical box beam framing

The corner box beams assist with keeping walls plumb during stacking and allow for a clean 90 degree corner plaster detail.

curb rail framing detail with pea gravel at void

The curb rails (sills) raise the bales off of the floor surface to prevent moisture from entering at the base. We have chosen a pea gravel infill between the curb rails since it was readily available and should assist with any drainage. Rigid insulation is also commonly used to fill this void.

first course of bales at north wall

In order to provide nailers for our j-bead plaster stop detail, blocking was installed between each bale of the first course at all walls. For a detail at the base of the exterior straw bale wall, click here

felt paper moisture protection at exterior walls

Due to the potential for snow build-up, felt paper was installed continuous from the top of the first course down to, and over, the top of the foundation wall.

detail of window buck framing (sill seen at top of photo) and felt paper at first course

a very happy and victorious looking brett

completed south and east walls (and a chilly-looking brett)

Prior to beginning plaster work in the next session a series of steps need to happen including felt paper and metal lath at all exposed wood to be plastered, j-bead plaster stop at the top and bottom of the walls and of course, the top plate/datum installation which will tie the whole system together. Check back for the next session’s progress!

As you may have already noticed, one of the primary design features of ‘el sombrero’ is the inverted truss roof form. Along with many other useful building materials and an already built CMU foundation, we found ourselves with 20 ‘traditional’ roof trusses and 2 gable end trusses. Utilizing the existing trusses in a ‘not-so-traditional’ upside down manner required modifications as all of the top chords now became bottom chords and new beams hidden within the truss cavity needed additional support. With much assistance from Rick (UCD Professor extraordinare) and Chris (Structural Engineer), we were finally able to complete the modification of 20 trusses using lumber already on-site as part of the home kit previously delivered. Two gable end trusses are awaiting modification (maybe) and five new trusses will need to be built in order to round out the new roof framing construction. In order to expedite modifications and get a consistent result (we hope), our newly sheathed floor, a.k.a. the dance floor, became a large level surface to set up a jig. Details of the jig and the steps involved are outlined below.

east side truss modification - step 1

A – existing truss to be modified
B – existing truss alignment block (ensures that each truss is positioned the same)
C – top & bottom chord separator (ensures that existing chords (A) don’t move when cut is made)
D – truss raising block (raises truss 1/2″ to prevent cutting into floor sheathing)
E – skilsaw leveling block (creates level surface for skilsaw between top & bottom chord cuts)
F – truss modification alignment block (creates proper angle and location for cut)

east side truss modification - step 2

G – removable cutting fence (this 2×6 and the alignment blocks (F) are set to the proper angle and distance so that measurements are not needed for each truss, just place the cutting fence against the alignment blocks and cut.

east side truss modification - step 3

H1 – new truss modification member (after the existing truss is cut, a new vertical member is added).

west side truss modification - step 1

H2 and H3 – new truss modification members (on the west side of the trusses no cutting was required, only the addition of a new vertical member as well as new top chord bracing. the top chord bracing shown (H3) was eventually re-done to butt up against the new vertical member (H2) in order to satisfy the specified overlap. Again, alignment blocks (F) are set to the proper angle and location so measurement of each truss is not needed).

truss modifications - final step

Partially modified truss seen in the jig on the ‘dance floor’. The final step involved flipping the truss over and adding additional top chord bracing (as seen in the stack of finished trusses)

the end

Completed stacks of modified trusses (and 2 gable ends to be modified).

Alright. I must confess. This process didn’t exactly proceed as smoothly as this post may seem. Although the lumber already on site was too short for added top chord bracing per Chris’s specifications, we decided to move forward with an alternate solution in the interest of time. Well, this sorta backfired. After thinking we were finished with half of the trusses, we received word that our alternate solution wasn’t sufficient due to an excessive cantilever on the west side of the roof. Needless to say, we became really good at stacking and re-stacking and re-re-stacking the trusses until the final photo seen above. Not too much extra time lost in the end and lots of good lessons learned.

The Revit model for El Sombrero has been a work-in-progress. As the details come into focus we will be updating the model. While we have decided to utilize AutoCAD to develop the working drawings, the Revit model has become a tool for studying massing and 3D dimensional aspects of the home as well as a tool to predict how the design may fuction in it’s passive heating and cooling strategies.

Since the solar study videos exceeded the max file size for the blog, the following images represent snapshots of the sun’s path across the home during both the summer and winter solstices.

During peak summer months, the current model is revealing that the sombrero is working rather effectively until approximately 3:30 pm when solar gain begins to penetrate the envelope. To mitigate this our current thinking is to utiilize sliding insulated panels at the western window wall (I hope that’s still accurate – the sunshade team may be able to elaborate more on that soon).

During peak winter months, the more passive south/southwest portion of the home is seeing solar gain throughout the day as expected. This may result in too much gain and/or glare in the afternoon hours which can again hopefully be mitigated to a degree by the sunshades and/or minimizing the amount of solar glazing. Realizing that it has been a large goal to provide large unobstructed views to the southwest, I may get yelled at for suggesting a reduction in glazing, but this is the beauty of the design/build process and the use of modeling software.

Summer Solstice Study, June 21, 2:00 pm

Summer Solstice Study, June 21, 3:30 pm

Summer Solstice Study, June 21, 5:00 pm

Winter Solstice Study, December 21, 10:00 am

Winter Solstice Study, December 21, 2:00 pm

Winter Solstice Study, December 21, 4:00 pm

2011 July 4

    I woke this morning to the sounds of trees rustling in the breeze and the rushing creek. The result of a record snow season. Life in Frisco, CO is a far cry from the 2 am closing time scream-fest at the bar across the street from our place in Denver. So when in Rome, do as the Romans do. I filled up the camelback, checked the air in the tires and was off on a mountain bike ride. It started out with two, but a busted rear derailleur thirty minutes in left me alone in the woods once again – I was the lucky one still pedaling. I wasn’t complaining either. I had been craving some solo time to reflect about everything going on. Sorry Kevin, no offense.

    Riding alone in the woods has been my predominant physical and mental therapy for some time now. This has largely been put on hold due to life in grad school. Five months on crutches after a broken tib/fib didn’t help either. Needless to say, I relished the situation I found myself in. First were the thoughts of nostalgia about how life has changed [for the better] since leaving the east coast – reclaiming my health, celebrating my one-year wedding anniversary (yesterday), finally going back to school. Life is good.

    And then there’s BLUFF. No bike riding therapy session could be complete these days without thoughts on BLUFF. How rare are those times in life when you feel so completely at peace with where you are in life. Whether the decision to pack up the car and leave the hustle and bustle of NYC or the day I proposed to my wife or currently, the decision to enroll in Design Build BLUFF. We are only six weeks in and thoughts of it all being over are already weighing on me. How will I return to a ‘normal’ studio? How do I return to thoughts of gainful employment in the city after being involved in such powerful and meaningful work? Not that architecture in general isn’t producing some powerful and meaningful work, but let’s face it, the profession has some flaws. The fact that it takes a non-profit to provide adequate housing to folks on the reservation is surely proof of that. Is it not? Surely there will be opportunities for continuing the path of socially responsible design AND paying off a mound of student loan debt. We shall see. I suppose I’ll cross that bridge when I reach it. For now I’ll only hope that Harold, Helena and Kaelan are pleased with what they are about to see. Just another day of soul searching and single-track.