• “Dad, go back to curtainwall, it’s much easier than stud walls.”

    This from my 25-year-old son while planning a basement finish-out at his sister’s house.  And, from someone I thought (hoped?) knew the irony in what he was saying after working part time for a couple of years at a former employer, helping the IT guys upgrade computers and asking questions on numerous rides home about the technicalities of curtainwall he had overheard at work.

    He certainly doesn’t know how simple stud walls are compared to the many facets of curtainwall and window glazing design, fabrication and erection.  Nor of the many intricacies of any one element of glass and glazing, aluminum extrusion, die design, gasketing, sealants, fasteners, etc., that go into good wall design and execution.  As we were only in the planning phase of the basement addition, I guess I’ll have to show him how easy some 16d nails and a good framing hammer really is in studwork.

    Speaking of curtainwall expertise, I’ve come across a book a good friend who wrote about the design and execution of good curtainwalls.  Keith Boswell has spoken at the BEC conferences a couple of times, and has now put his vast knowledge down on the written page.  I don’t think I’ve met many architects on par with Keith’s experience and his willingness to get into the guts of a system.  Not many architects care or even know how these systems work.  Keith does.

    The book, “Exterior Building Enclosures:  Design Process and Composition for Innovative Facades,” is written from an obvious architectural perspective, but it’s a comprehensive review of the process leading up to the point where the glazing trade becomes involved in the work. One thing that makes it particularly effective is Keith’s highlighting of the execution of several projects.  Having worked on a couple of the projects cited in the book, I found it insightful.  I certainly had no idea how much work can and should go into the design process prior to when the drawings first come across our desks. And, when that work doesn’t happen, it’s painfully obvious.

    Equally as important was his coverage of the technical side. His thorough explanation of how a wall resists air and water penetration, how the exterior skin, regardless of the material, must respond to thermal changes, building movement, seismic or other forces and how anchorage impacts other parts of the building besides structural — all of which must also meet the aesthetic demands of a design –  makes the book a great primer for those new to the industry.   So, if you’re looking for a Christmas gift for your staff or your architect friends, start there.  You and they will be better for it, you’ll have a reference point to send them to when issues come up and you’ll get a better appreciation for where they’re coming from.   If nothing else, it’s a resource that can be cited to show how an issue can be resolved, rather than just relying on “gut feel” or “experience.”  Having an external reference can only help, right?

    I had an experience this past week that made this especially relevant:  a mock-up install currently going on with testing next week for a variation of a standard / customized curtain wall.  I’ve said it in the past, I’ll say it again:  Mock-ups are expensive and they’re tough to justify within the overall cost of a building, but there’s always something learned.  Mock-ups provide crucial knowledge about what can be changed in the fabrication of material and how the install can be made easier and demonstrate how the wall will perform before the job starts.

    By the time you read this, wish us luck.  We’ll be starting the testing tomorrow.  Anyone who’s ever lived through the rigors of a mock-up knows the longest 15 minutes of your life is inside a chamber at a test lab during a water test.  My wife’s labor with our first-born was close to 40 hours.  Those 15 minutes seem infinitely longer.  (Please don’t tell her I said that.)

  • Did you see the monster-size (46’-0” x 10’-6”) laminated glass lite seele displayed at the AIA show in Denver?  Impressive, to say the least!  Congratulations to seele for pulling it off.  It was certainly a conversation starter, and I think it has many of us in the industry curious about several things – new technology is like that.  First, it leaves us wondering, “How did they do it?”

    Out of curiosity, I ran some numbers on what size framing it would take to support a lite like that.  Assuming a 40 psf design windload, and a weight of glass roughly 14 lbs/sf (two lites of ½” thick glass), yielded  the following:

    1. If the glass were  stood up (10’-6” wide x 46’-0” tall), with the 46’-0” long mullion at either edge anchored at the ends only and another lite in the next module was the same size, a steel rectangular mullion would have to be at least a TS 4” x 20” x 3/8” thick walls or 3” x 16 ½” deep, with 1” thick front and back walls and ½” side walls.
    2. The deadload weight of the glass is roughly 6,762 lbs. If the lite were to be supported off a single 46’-0” long horizontal supported only at each end, a W24 x 192 I-Beam  cambered so it would be perfectly horizontal when loaded, or a rectangular tube steel member, would have to be 17” x 36” with 1” top and bottom wall thickness and ½” front and back.  The setting blocks are located at the eighth-points.
    3. Conventionally speaking, the setting blocks would have to be 48” long each.  Would a Shore A 90 durometer (+/-5) setting block still work?  If the 46’ long horizontal were perfectly flat, no issues, but, if it deflects at all, the deflection of the horizontal (without the camber mentioned above) just between the ends of the 4’ long setting block is almost 1/16” across that length.  So in theory, only one end of the setting block is in contact with the glass.  Would a tapered block, thicker at one end than the other be required?

    TGP is often asked how big a lite our framing systems can support.  And, the question usually evolves into a discussion about who can make what size, whether the glazier can handle that size lite, and whether the budget can accommodate the larger lite sizes (see March 6, 2013 blog).

    Which brings me to other questions around making a lite that size.  The video of Lyle Hill walking down its length is pretty impressive, but, as with most new technologies, were you left asking more questions than the video answered?

    1. Just how much more expensive is it to make a lite like that over the largest commercially available lite now on the market?  Would the owners, architects and general contractors have enough information to include this cost in their budgets?
    2. As to the actual manufacturing:
      1. If the float line can make the glass 10’-6” wide, cutting it to length every 46’ is no big deal, maybe?
      2. To make one lite is pretty impressive,  but as the video explains, this is a laminated-lite, so they had to do it twice.
      3. Just out of curiosity, how many lites did they make and break before they got these two to the next production step?  Or through the entire process?  What was the fall-back if this one had broken in transit?  Was there a spare standing by?
      4. How was it laminated?  The process I’m familiar with involves an autoclave, subjecting the laminating sandwich to a vacuum and temperature to meld the components together into a cohesive unit.
      5. What if there’s silk screening or coating involved?   The glass in the AIA show was said to be low-iron, so no coating, but someone’s going to want to put a low-E coating on something like this sooner or later, right?
      6. Can lites this size be made into an IGU?  What’s the required thickness of that construction?  And how is that picked up and handled?
      7. What’s the lead time for making large lites using this process?
    3. Between any of the required production process points, how were the lites moved and transported?  What does the machine look like that picked it up?  Or was it done in a continuous line?
    4. Say you actually get a job with lites this size.  Do you buy any extras in case one is broken?
    5. How was it transported from Germany to the U.S.?  Most shipping containers are limited to 40’-0” lengths  x 8’-0” heights (inside dimensions are smaller than that).  We know we can get closed topped containers up to 45’-0” long.   Longer containers are available, but most are limited to rail transport here in the states, not overseas shipments.  How was all this managed?  Does it take a custom container? How did it get put in the container?  And, how blue were the parties from holding their breath between closing the container on the shipping end and opening it on the receiving end?
    6. The day finally arrives, and if all goes well, the truck with the glass just pulled up to the jobsite.  How does one get it off the truck and into the hole?  The glass cup rigs to pick up a nearly 6,800 lb. monster lite better have a huge compressor rig attached.  Someone want to venture how many large vacuum cups it would take to pick this lite up?  A normal vacuum cup is rated for 125 lbs.  That makes 55 cups required, assuming you can keep them all pumped at the same time AND could lift them all at the same time. That rig’s got to be huge!

    I would pay the ticket price to see the video of this lite being made.  The lite itself is impressive as all get out, no doubt, and seele, you’ve got a bunch of people out here wondering how you pulled this off.  A video, if it can be done without divulging proprietary processes, would be of great interest, at least to this writer.

    Warning, shameless plug coming:  If a system to frame something like this is required, or something a little smaller, say 10’-6” x 20’-0” long, you know where to reach me.



USGlass Magazine

USGlass Magazine