Flashing


   What flashing must accomplish.
           How water moves.
      Thinking out the details.
What flashing must do

 • Collect
   – Gather water which infiltrates
   – Be everywhere it is needed
   – Deal with all t...
Working with flashing

 Prescriptive:
      Follow the rules, codes, manufacturers’
      specific guidelines and recommen...
What BIA has to say
Brick Industry Association Technical Notes
7-1998
Flashing is a membrane, … which collects water that
...
What BIA has to say


 7-1998
 End Dams - Where the flashing is not continuous, such
 as over and under openings in the wa...
What lawyer bait might say
 I do not want to see the flashing.

 Flashing is too ugly, … too difficult, …
 too expensive, ...
Why flashing is needed
The wall WILL leak.
    Immediate:
        Masonry permeability, stucco permeability
        Draina...
Where it is needed - masonry
             Wall roof
   Coping
             intersection
Shelf
angles

 Lintels,
 heads


 ...
Where it is needed - residential
                  Roof-wall
  “Kick-out”
                                  Window +
Chimn...
Ways water can move

      Gravity
      Kinetic energy
      Surface tension
      Capillary suction
      Air currents
 ...
Gravity
Kinetic energy
Surface tension
Surface tension
Capillary suction
Air currents
Differential pressure




                        Head
Wind patterns


     Upward
    Sideways
Resisting intrusion – face seal
Resisting intrusion – cavity

                        C
                        A
                        V
              ...
Resisting intrusion – rain screen
                       D
                       R
                       A
             ...
Resist intrusion – pressure


                       C
                       O
                       M
                 ...
Window sill
Window sill
Add sealant
Window sill
Add flashing
Window sill
Add upturn
Window sill
Relocate the sealant
Window sill
Add air seal
Visualize in three dimensions
End dams
Fold an end dam
Other atypical locations
What happens at other locations away from
the typical cross-section?
        • Inside corners
   ...
Secret of flashing


  Think like water.
     Effective flashing results
  from a thought process, not a
             rule...
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Flashing 101 by The SC Property Pros Charleston SC

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Flashing and the basics

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Flashing 101 by The SC Property Pros Charleston SC

  1. 1. Flashing What flashing must accomplish. How water moves. Thinking out the details.
  2. 2. What flashing must do • Collect – Gather water which infiltrates – Be everywhere it is needed – Deal with all the ways water can move • Control – Capacity to retain water until it drains – Prevent bypass flow • Discharge – Get the water out of the wall – Path to daylight
  3. 3. Working with flashing Prescriptive: Follow the rules, codes, manufacturers’ specific guidelines and recommended practices, and the construction documents. Conceptual: Does the flashing as-recommended, as- designed or as-built do everything it should (collect, control, discharge)? Good flashing requires a thought process, not just rules.
  4. 4. What BIA has to say Brick Industry Association Technical Notes 7-1998 Flashing is a membrane, … which collects water that has penetrated the exterior wythe and facilitates its drainage back to the exterior. 7-1992 Flashing is essential in a drainage wall system… 21B-1998 … the flashing should extend through the outer face of the wall and be turned down to form a drip …
  5. 5. What BIA has to say 7-1998 End Dams - Where the flashing is not continuous, such as over and under openings in the wall, the ends of the flashing should be extended beyond the jamb lines on both sides and should be turned up into the head joint several inches at each end to form a dam.
  6. 6. What lawyer bait might say I do not want to see the flashing. Flashing is too ugly, … too difficult, … too expensive, … too time consuming, … not my problem. EIFS doesn’t leak. We have never used it, … never had a problem. What the heck is an end dam?
  7. 7. Why flashing is needed The wall WILL leak. Immediate: Masonry permeability, stucco permeability Drainage and pressure equalized systems Internal weeps and drains Non-performing subsystems Future: Deterioration, UV degradation Cracking De-bonding Unbalanced useful life Maintenance deferred
  8. 8. Where it is needed - masonry Wall roof Coping intersection Shelf angles Lintels, heads Sills Foundation
  9. 9. Where it is needed - residential Roof-wall “Kick-out” Window + Chimney door heads cap Chimney roof Balcony Deck Window + door sills Foundation
  10. 10. Ways water can move Gravity Kinetic energy Surface tension Capillary suction Air currents Differential pressure
  11. 11. Gravity
  12. 12. Kinetic energy
  13. 13. Surface tension
  14. 14. Surface tension
  15. 15. Capillary suction
  16. 16. Air currents
  17. 17. Differential pressure Head
  18. 18. Wind patterns Upward Sideways
  19. 19. Resisting intrusion – face seal
  20. 20. Resisting intrusion – cavity C A V I T Y
  21. 21. Resisting intrusion – rain screen D R A I N A G E P L A N E
  22. 22. Resist intrusion – pressure C O M P A R T M E N T
  23. 23. Window sill
  24. 24. Window sill Add sealant
  25. 25. Window sill Add flashing
  26. 26. Window sill Add upturn
  27. 27. Window sill Relocate the sealant
  28. 28. Window sill Add air seal
  29. 29. Visualize in three dimensions
  30. 30. End dams
  31. 31. Fold an end dam
  32. 32. Other atypical locations What happens at other locations away from the typical cross-section? • Inside corners • Outside corners • Expansion joints • Transitions to other cladding materials • Laps, splices • Ends
  33. 33. Secret of flashing Think like water. Effective flashing results from a thought process, not a rule book. Keep Dry

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