How to back flash sheathing that extends past foundation?


  #1  
Old 06-15-24, 10:45 AM
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Question How to back flash sheathing that extends past foundation?

Hi everyone, hope you're doing well. I'm rebuilding a deck, removed the ledger, and about to back flash with butyl tape over the sheathing before mounting a new ledger. However, I noticed the sheathing actually extends out past the upper edge of the foundation and I'm wondering: should the butyl tape cover only the front face of the sheathing, leaving the bottom edge of sheathing exposed, or should I instead begin laying tape on the foundation itself, bend it up around the lower sheathing edge, and continue it up the face of the sheathing?

I'm unsure if wrapping the butyl around sheathing like that will help prevent water from running back into rim joist, or if it'll instead trap any potential water that does get in. Thanks for your time.

 

Last edited by FieldNotes; 06-15-24 at 10:46 AM. Reason: Moved the image.
  #2  
Old 06-15-24, 11:55 AM
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You could cap it with a metal z flashing, just to ensure it stays dry. Will the ledger cover it completely, or will a portion of it be exposed below the ledger?
 
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Old 06-16-24, 03:53 AM
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Thanks, the ledger will cover it completely so I'm not sure I'll have the option to do another z flashing on bottom (one will be on top of ledger board). Just wondering if I should butyl wrap the sheathing edge or leave exposed.
 
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Old 06-16-24, 06:41 AM
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1/2" z flashing would get turned around backward to cap the bottom, it would not stick out. Butyl not only may not stick well if it gets wet, but yeah it would trap water if it ever got behind.
 
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