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Green Building Curmudgeon

Topping Out

Framing is wrapping up, not without some hitches

Zip-R sheathing with R-3 polyiso insulation integrated on the back side simplifies the installation of a continuous exterior insulation by making it a one-step process. Insulation, OSB, and weather barrier are all installed in one step.
Image Credit: Carl Seville
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Zip-R sheathing with R-3 polyiso insulation integrated on the back side simplifies the installation of a continuous exterior insulation by making it a one-step process. Insulation, OSB, and weather barrier are all installed in one step.
Image Credit: Carl Seville
Zip tape is applied to the corner of the wall and the attic floor sheathing to create an air barrier before the roof is framed. The purpose of the band joist is to raise the rafter tails. This provides enough room under the rafters up to allow for full-depth insulation at outside of the wall framing. Seams in the Zip sheathing on the attic floor will be taped before insulation is installed. A view of the attic framing and sheathed floor. The house is almost dried in — just waiting for tape on the roof decking. The porch roof and carport are framed.

Carl Seville and his wife are building themselves a new home in Decatur, Georgia. The first blog in this series was titled The Third Time’s the Charm. Links to all of the blogs in this series can be found in the “Related Articles” sidebar below.

Once we finished all the foundation and termite protection work describe in my last post, we were ready to start framing. Before we hired the framing trade contractor, I reviewed my requirements with him, including advance framing and close communication, and I looked him in the eye and said I was looking for a quality job and was willing to pay for it — I didn’t want an industry standard, crank-it-out-fast crew.

He agreed, but proceeded to send out the wrong crew. My initial impression was good, possibly because their leader spoke fluent English, which is often a rarity in our area. This impression was quickly changed as it appeared they had not been properly briefed by their boss on my requirements. They built hollow headers instead of pushing the framing to the exterior. They installed extra, unnecessary cripple studs under window sill framing, after I requested they leave them out. Doors and walls were framed incorrectly. Walls were out of plumb.

What finally got to me was the floor joist installation. Although I did not need the pre-cut duct holes in the I-joists, they came with 2 holes in each one. The framers decided to ignore them and install the joists with many of the holes misaligned. I pointed this out to them as soon as they started, but not only did they not correct the mistake, they continued to do the same thing on the next set of joists they installed. Luckily I don’t need the holes for ductwork, but it does look pretty amateurish.

After two days of struggling to get what we wanted, their boss pulled them off the job — something I expect pleased them as much as it pleased me. The replacement crew showed up a couple of days later, and although the results haven’t been perfect, they are much better. There are still some details I don’t care for, but overall their work has been much better, and they have listened to our concerns and, in general, framed the house the way we wanted.

OK, enough whining — down to the details

On the bright side, the house does include all the advanced framing details I requested: 2-stud corners, ladder-T walls, right-sized headers, Zip-R insulated sheathing, and decking on the second-floor ceiling joists to serve as the air barrier on top of the house. Zip sheathing was installed on top of the 9-inch I-joists we used for the top floor ceiling before the roof was framed.

Corners between the wall and ceiling sheathing were taped before the roof was framed (see Image #2, below). Before insulation is installed we will tape the balance of the attic decking, creating a complete and continuous air barrier from the sides to the top. Combined with tape between the bottom of the wall sheathing and the foundation, there will be minimal air leakage without using spray foam (except for some foam to seal around windows and doors).

I plan to do a blower-door test as soon as all the mechanical work is complete to see how tight the envelope is, and identify any areas requiring additional air sealing.

Next steps

Windows will be arriving in the next week. We selected the Pinnacle aluminum-clad wood series from Windsor, with simulated divided lights. Glazing is low-e 366, providing a U-factor of 0.30 and a SHGC of 0.18 — about as good as we need in Climate Zone 3. Lower values would not have provided enough return on investment to justify the initial cost. The windows will be installed using Zip stretch tape on the sills and standard Zip tape over the top and side flanges.

Next will be plumbing rough-in. I have located the water heater in a central mechanical closet, allowing me to install a short home run to each hot water fixture. The plan is to use a ½-inch PEX insulated hot water line directly to each bathroom, the laundry, and the kitchen to minimize any water waste.

Fixtures and fittings will be coming from American Standard. I am currently trying out several Watersense shower heads to determine which one I like the best.

I expect to be on site a lot when the plumbing is being installed to make sure the hot water system is installed properly.

Following plumbing will be HVAC and electrical roughs; reports on those installations will be forthcoming.

Lessons learned

Getting the right framing crew on site was a frustrating process, reminding me yet again why I got out of the construction business. In a construction climate where any trade can charge whatever they want and behave however they like, it is challenging to find the right team, let alone anyone, to do your work.

A friend of mine recently told me a story he heard from one of his production builder clients. The supervisor was driving through a subdivision and came upon one of his subcontractors urinating in the middle of the street. When the super asked him what he was doing, his reply was, “What are you going to do, fire me?”

We will aim to do some better vetting on the next trades, particularly the interior and exterior trim crews. Preparing clear scopes of work combined with detailed drawings is only half the battle of getting what you want out of trade contractors. The rest involves supervising the work closely and making necessary adjustments frequently to keep things on track.

And people wonder why high-quality construction costs so much…


  1. STEPHEN SHEEHY | | #1

    Is there some reason you went with rafters as opposed to raised heel trusses?

  2. Expert Member
    CARL SEVILLE | | #2

    Stephen - since I am using the sheathing on top of the 2nd floor ceiling joists for my air barrier instead of drywall on the bottom of the trusses, it made more sense to stick frame the roof. It's a somewhat unusual design, partially inspired by Passive House techniques. I expect that it will give me an excellent air barrier and allow me to get to a very high performance building envelope without using spray foam, something I wanted to try out.

  3. JC72 | | #3

    Great idea to use ZIP on the attic floor.
    I'm guessing it will make sealing any penetrations (bathroom exhaust, supply/exhaust for HVAC) much easier.

    Will you still have to seal the drywall on the second floor?

    Sorry to hear about your initial troubles with the framing crew. I've been told that the labor pool in Atlanta is tight.

  4. GBA Editor
    Martin Holladay | | #4

    Response to Chris M
    For more information on the use of OSB as a ceiling air barrier, see these two articles:

    Service Cavities for Wiring and Plumbing

    Net-Zero Homes Show Signs of Convergent Evolution

  5. STEPHEN SHEEHY | | #5

    Reply to Carl
    I understand the air sealing issue, but using trusses would have avoided the need to add band joists on top of the deck as your photo shows.
    What keeps the band joists from being thrust out by the rafters?

  6. Expert Member
    CARL SEVILLE | | #6

    Reply to Stephen
    I understand you point about the band joist, but trusses would have had a bottom chord sitting on top of the zip sheathing deck since they would not be used for the ceiling plane to hang drywall. Stick framing in a case like this, particularly with a hip roof where each truss would be unique, is probably about as efficient as trusses. Like most things in construction, there isn't a definitive answer for every choice. I decided to frame the house this way because it made the most sense for me. If you want to frame with trusses have at it. On the band joists - it is strapped on the exterior with metal and blocked back with wood on the interior. No sign of any movement.

  7. Expert Member
    CARL SEVILLE | | #7

    Reply to Chris
    All my exhaust fan ducts will go to the exterior through the 2nd floor ceiling I joists . The only penetrations in the attic decking will be for an access hole, a radon pipe, and some wiring, easy to seal to the Zip. No need to air seal the 2nd floor ceiling, although I will insulate the band area above interior walls for sound.

  8. Expert Member

    The band joist worried me too. Because it's a hip roof, the roof sheathing has probably ended up acting as a diaphragm resisting the horizontal forces. From a code standpoint, ours would require either rafter ties in the bottom third of the spans, or mechanical attachment directly to the roof deck.

    I like the idea of a separate air-sealed roof deck, but I'm not sure that in most situations there are enough penetrations or duct work to justify the time and expense. To me, modifying the trusses to include a conditioned mechanical space seems like a better idea, but Carl isn't exactly new at this, so I'm sure he considered the alternatives and make a conscious decision he wanted it.

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