External Framing Completed

The basic frame and all Zip sheathing was completed on September 16th.

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In the two photos below, you’ll see how the Zip is being wrapped over the top of the second floor walls.  Once we prep for the future attic insulation (we need to install some type of baffle to retain the 18″ of cellulous),  Zip will be installed on the rest of the second floor ceiling and the seams will be taped.  As can be seen in the following photos, the finished side will face down.  It could have gone either way, but since the tape will be placed on the bottom, this seemed to make most sense.

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That’s 1/2″ Zip in the photos above.  The same thickness we used on the exterior walls (we used 5/8″ Zip on the roof).  Looking back, we could have saved a bit of weight and money by using 7/16″.  I was a bit concerned with the ability of the roof trusses to hold the weight of the drywall, zip, and 18″ of insulation.  But they’re engineered to support 10lbs/sqft, which provides a reasonable margin of safety, as the weight of the drywall, Zip, and insulation amounts to less than seven.

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The combination of perspective, background lighting, and lack of windows and porch make the house look mighty small.  Hard to believe that its over 2,000 square feet.

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The rest of the Zip was taped a couple of days later.  The Zip tape dispenser/roller proved difficult to use effectively.  The roller seems to have a slight crown that makes it difficult to seal the edges and causes the roller to drift.  But the job was completed:

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The Framing Continues

By September 5th, most of the necessary framing materials had been purchased and assembled, and the framers started working up from the first floor decking.

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The longest wait was for the trusses that will be used for the roof, porch, pents, and the second floor.  Unlike the first floor (where we used Flack Jacket I-Joists), we’re using floor trusses for the second floor because we’re figuring that they will make it easier (than I-Joists) to route the pluming, the heat pump lines, and the ERV ducting.  The following photo shows the floor trusses, along with a bit of post and beam work created by the builder, Hugh Lofting Timber Framing, that will define the division between the kitchen and dining area (and also the fir beams that will be above the kitchen/living area):

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As shown in the photos, a number of the key principals of “advanced framing” are being applied to the shell structure; framing 24″ on center;  joists, studs and trusses will be “stacked” (i.e. line up); single headers; single top plates, and two-stud corners.  This is new to everyone involved in the project.  So the pace was slowed down to ensure that the essential details were correct.  We lost count on the number of tubes of polyurethane caulk used.

We’re using Huber’s Zip System for the exterior sheathing, which  think is pretty common these days.  But since we are framing at 24″ on center, and I wanted to ensure a bit extra structural support, I opted for the half inch Zip for the walls, rather than the more common 7/16″.  That decision resulted in an upcharge of approximately $1.30 per sheet ($21.75 vs $20.45).  Basically, the entire shell will be covered with the Zip sheathing.  The 1/2″ product will be installed on all vertical exterior walls and the second floor ceiling.  A 5/8″ version of the product will be used for the roof.  Of course, all of the seams will be sealed with the Zip tape, at about $26 per roll.  The estimated use is one roll for every 7.5 panels.

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As the photo indicates, when initially completed, the shell will only have one opening, which will be for the front door (the basement windows and the door in the Bilco well will also be installed).  Once the blower door test passes the Passive House standard of .6 ACH @ 50 pascals, the windows and the two remaining doors will be installed, and the shell will be retested.

By COB on September 11th, the framers were closing in on completion of the second floor.  Here’s a couple of photos from earlier in the day:

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