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“I can’t install this” – Poka Yoka (mistake proofing) on my job site

  My college degree is in Industrial Management, and a good portion of my studies were about Japanese Management Techniques.  In the 1960’s Toyota had a very astute Industrial Engineer named Shigeo Shingo (he was a W Edwards Deming student) who is credited with the technique of Poka Yoka. Poka-yokes ensure that proper conditions exist before actually executing a process step, preventing defects from occurring in the first place.

  Here’s how Poka Yoka works on my job sites:  
#1 Don’t bid your key trades.  The carpenter should know when there is a defect in the plumbing, the plumber should know when he’s interferring with HVAC, and the Electrician should know where/when he can drill through some studs, etc.  You need the same trades on all your job sites to look out for one another, and for your clients!  The low bidder just isn’t interested in finding a problem.  He needs to get done and get to the next job.  
#2 Train, Train, Train.  My Project Managers are constantly training our sub-contractors on how we want things done.  The Risinger Way.  We use my YouTube videos, Manufacturer’s manuals, and we review at the end of each job how we could have built it better.  
#3 Don’t be afraid to stop work!  Here’s where Poka Yoka comes into play….
I was walking a house in the framing stage Friday.  The trades had started work, HVAC was 3/4 finished with duct work, plumbers just started, so had electricians.  Our framing crew also does the exterior woodwork, siding, window install, and rigid foam.  The framer stopped me and said:  “I can’t install siding here.”  Here is what he was pointing towards on this gable where siding was being installed.  There is a 6″ bath exhaust fan penetration.  You’re seeing the Hardie installed over Rain Screen, which is on top of 3/4″ R-Max foam, over Tyvek Drainwrap.  

  That’s not good!  Unflashed penetration! STOP!!!
  It could be caulked on the inside to prevent air flow, but that wouldn’t stop water from working in to the wall cavity and rotting the house out.  This type of error happens daily on job sites around Austin but clients won’t know there is a problem till 5-10-15 years later when it’s a major issue to fix.  My guy was correct in saying STOP.

 These penetrations need a gasket boot from QuickFlash that seals the duct much like a roof penetration.

 That boot is then properly taped to the Tyvek layer with Tyvek tape for a water & air tight seal.  This method isn’t dependent on caulking the siding to prevent water infiltration.

 All done. Much better!

 This penetration is under the roof overhang, but a windy rainstorm could have easy wet the wall in this location and caused moisture intrusion.

 Hard to see in this photo, but the windows are “trim less”.  We used a metal flashing all around the windows to give the window flange the depth we needed for the foam and the rainscreen battens then Hardie Plank siding.


 Side note here, but I really like the outside corner detail specified by Scott Ginder the Architect with Dick Clark Architects.

I’ve always been a fan of Toyota vehicles, they learned all these management techniques post WWII from the Americans.  It’s fun to apply these principles to my houses in the pursuit of excellence.  -Matt Risinger Risinger Homes in Austin, TX