Rain. Building Science. Rain is the largest source of moisture We need better control for better insulation and airtightness Rain penetration control

Transcription

1 Rain Control Layer Air Control Layer Vapor Control Layer Thermal Control Layer Rain Control 1 Rain Control 2 Rain Rain Control Rain is the largest source of moisture We need better control for better insulation and airtightness Rain penetration control Site and massing Surface features Enclosure wall strategy presented by Straube buildingscience.com 1 of 22

2 Controlling Rain Penetration Deflection reduce water on building redirect water away slope surfaces, use flashing Drainage / Exclusion / Storage enclosure design provide drainage, or storage or barrier Drying allow any remaining water to dry Deflection! Surface & site features are also important Rain Control 7 Straube buildingscience.com 2 of 22

3 Don t concentrate water! 9 Categorization Elements and joints can be different 2008 Joseph Lstiburek Rain Control 12 Straube buildingscience.com 3 of 22

4 Claddings that leak Brick Stucco Wood, vinyl, fiber cement Adhered veneer EIFS Metal panels, metal roofs Shakes, shingles Rain Control 13 Rain Control 14 Drainage Requirements Drained Walls Must have continuous drainage plane Drainage plane must be: 1. Water tolerant 2. Capillary inactive (water repellent / non-wicking) Small gap required As small as 1 mm Flashing is very important Weep holes Terms: sheathing membrane, building paper, housewrap, Stupid terms: weather resistant barrier (WRB) Drainage plane Water repellent, continuous Drainage gap 1/16 is enough! Flashing Waterproof to direct water outward Weep holes Above grade Rain Control 16 Straube buildingscience.com 4 of 22

5 Drainage Plane Lapped Housewrap, paper Rain Control 17 Rain Control 18 Drained Walls Rain Control 19 Rain Control 20 Straube buildingscience.com 5 of 22

6 Laps are the most reliable 21 Rain Control 22 Drained gap behind brick Laps are the most reliable Rain Control 23 Rain Control 24 Straube buildingscience.com 6 of 22

7 Liquid applied = continuous Rain Control Joseph Lstiburek Rain Control 26 Beware: These are vapor barriers!!! 2008 Joseph Lstiburek Rain Control 27 Straube buildingscience.com 7 of 22

8 Drainage Gaps Gap avoids hydrostatic pressure drains away water Requires only small gap, e.g. 1/16 Reduces time of wetness on housewrap sheathing membrane May allow ventilation drying if >1/8-1/ Joseph Lstiburek Rain Control JJAC Test house 2001 Stucco sticks to paper/ housewraps leaks Straube buildingscience.com 8 of 22

9 33 Water drained astonishingly well between sheets of building paper 34 Ventilation helps drying. Not always needed. Vinyl drains well with no strapping 35 Rain Control 36 Straube buildingscience.com 9 of 22

10 Drained gap behind wood Joseph Lstiburek Rain Control 39 Rain Control 40 Straube buildingscience.com 10 of 22

11 Water can build up here -- we need a waterproof barrier Note standing water J. Straube Continuity at Corners J. Straube New materials Rain Control 43 Rain Control 44 Straube buildingscience.com 11 of 22

12 2008 Rain Control Rain Control 47 Straube buildingscience.com 12 of 22

13 E.g. StoCorp Diverter Flashing 2008 Joseph Lstiburek Rain Control 49 J. Straube Rain Control 51 J. Straube Straube buildingscience.com 13 of 22

14 Saddle flashing 2008 Joseph Lstiburek Rain Control Joseph Lstiburek Rain Control 54 University of Waterloo Rain Straube buildingscience.com 14 of 22

15 Exterior sealant is temporary, aesthetic, water shedding layer Leaky windows Moisture sensitive substrates are a problem J. Straube com 59.com 60 Straube buildingscience.com 15 of 22

16 Rain Control 61 Rain Control 62 Rain Control 63 Joseph Lstiburek Rain Control 64 Straube buildingscience.com 16 of 22

17 J. Straube Joseph Lstiburek Rain Control 66 Joseph Lstiburek Rain Control Straube buildingscience.com 17 of 22

18 Door Sills Door sill Joseph Lstiburek Rain Control Joseph Lstiburek Rain Control 72 Straube buildingscience.com 18 of 22

19 Rain Control Joseph Lstiburek Rain Control 74 Rain Control 75 Rain Control 76 Straube buildingscience.com 19 of 22

20 Old EIFS Substrate + moisture = problem Moisture sensitive substrates are a problem Rain Control 77 EIFS & Rain Control: Recent lessons on how to fail Kitchener, ON Grand Rapids, MI 2008 Joseph Lstiburek Rain Control 80 Straube buildingscience.com 20 of 22

21 EIFS J. Straube Rain Control Joseph Lstiburek Rain Control 84 Straube buildingscience.com 21 of 22

22 2008 Joseph Lstiburek Rain Control Joseph Lstiburek Rain Control 86 Conclusions Drainage is the key, cladding leaks All penetrations need to be drained! Beware flashing, it needs to waterproof Understand older systems are different 87 Straube buildingscience.com 22 of 22