Building Science 2008 Joseph Lstiburek – Rain Control 1

Building Science Joseph Lstiburek – Rain Control 2

Rain Control Layer Air Control Layer Vapor Control Layer Thermal Control Layer

Building Science

Rain Control

presented by www.buildingscience.com

Rain

•  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

Rain Control

Straube Charleston Building Enclosure Council 20101022 1 of 24

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

Building Science – Rain Control 7

Rain Control

Straube Charleston Building Enclosure Council 20101022 2 of 24

9

Don’t concentrate water!

Categorization

•  Elements and joints can be different

John Straube

Mass/Storage/Reservoir Walls

Rain Control

Straube Charleston Building Enclosure Council 20101022 3 of 24

Building Science Rain Control 13

Building Science 2008 Joseph Lstiburek – Rain Control 14

Building Science Rain Control 15

Categorization

•  Elements and joints can be different

Rain Control

Straube Charleston Building Enclosure Council 20101022 4 of 24

Claddings that leak

•  Brick •  Stucco •  Wood, vinyl, fiber cement •  Adhered veneer •  EIFS •  Metal panels, metal roofs •  Shakes, shingles

Building Science Rain Control 17

Building Science 2008 Rain Control 18

Building Science 2008 Joseph Lstiburek – Rain Control 19

Building Science 2008 – Rain Control 20

Rain Control

Straube Charleston Building Enclosure Council 20101022 5 of 24

Drainage

•  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)

Requirements Drained Walls

•  Drainage plane •  Water repellent, continuous

•  Drainage gap – 1/16” is enough!

•  Flashing – Waterproof to direct water outward

•  Weep holes – Above grade

Building Science Rain Control 22

Building Science – Rain Control 23

Drainage Plane Lapped Housewrap, paper

Building Science Rain Control 24

Rain Control

Straube Charleston Building Enclosure Council 20101022 6 of 24

Drained Walls

Building Science Rain Control 25

26

Laps are the most reliable

Building Science Rain Control 27

Liquid applied = continuous

Drained gap behind brick

Building Science Rain Control 28

Laps are the most reliable

Rain Control

Straube Charleston Building Enclosure Council 20101022 7 of 24

Building Science 2008 Joseph Lstiburek – Rain Control 29

Building Science 2008 Joseph Lstiburek – Rain Control 30

Beware: These are vapor barriers!!!

Building Science 2008 Joseph Lstiburek – Rain Control 32

Rain Control

Straube Charleston Building Enclosure Council 20101022 8 of 24

Building Science – Rain Control 33

Ventilation helps drying. Not always needed.

34

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”-1/2”

Rain Control

Straube Charleston Building Enclosure Council 20101022 9 of 24

Weep holes

40

JJAC Test house 2001

Rain Control

Straube Charleston Building Enclosure Council 20101022 10 of 24

41

Stucco sticks to paper/housewraps

•  leaks

42 Water drained astonishingly well between sheets of building paper

43 44

•  Vinyl drains well with no strapping

Rain Control

Straube Charleston Building Enclosure Council 20101022 11 of 24

Drained gap behind wood

46

Building Science 2008 Joseph Lstiburek – Rain Control 47

J. Straube 2002 48

Water can build up here -- we need a waterproof barrier

Note standing water

Rain Control

Straube Charleston Building Enclosure Council 20101022 12 of 24

J. Straube 2002 49

Continuity at Corners Base Flashing

Building Science 2008 Joseph Lstiburek – Rain Control 51

Building Science 2008 Joseph Lstiburek – Rain Control 52

Rain Control

Straube Charleston Building Enclosure Council 20101022 13 of 24

Building Science 2008 Joseph Lstiburek – Rain Control 53

New materials

Building Science Rain Control 54

Building Science 2008 Rain Control 56

Rain Control

Straube Charleston Building Enclosure Council 20101022 14 of 24

Building Science 2008 Rain Control 57

Building Science 2008 Joseph Lstiburek – Rain Control 59

J. Straube 2002 60

E.g. StoCorp Diverter Flashing

Rain Control

Straube Charleston Building Enclosure Council 20101022 15 of 24

Building Science – Rain Control 61

J. Straube 2002 62

Building Science 2008 Joseph Lstiburek – Rain Control 63

Saddle flashing

Building Science 2008 Joseph Lstiburek – Rain Control 64

Rain Control

Straube Charleston Building Enclosure Council 20101022 16 of 24

Building Science University of Waterloo

Rain

J. Straube 2002 67

Exterior sealant is temporary, aesthetic, water shedding layer

Leaky windows

•  Moisture sensitive substrates are a problem

Rain Control

Straube Charleston Building Enclosure Council 20101022 17 of 24

Building Science.com 69 Building Science.com 70

Building Science Rain Control 71

Building Science Rain Control 72

Rain Control

Straube Charleston Building Enclosure Council 20101022 18 of 24

J. Straube 2002 73

74

75

Door Sills

76

Door sill

1932

Rain Control

Straube Charleston Building Enclosure Council 20101022 19 of 24

Building Science 2008 Joseph Lstiburek – Rain Control 77

Building Science 2008 Joseph Lstiburek – Rain Control 78

Building Science 2008 Joseph Lstiburek – Rain Control 79

Building Science Rain Control 80

Rain Control

Straube Charleston Building Enclosure Council 20101022 20 of 24

Building Science Rain Control 81

Old EIFS

Building Science – Rain Control 82

Substrate + moisture = problem

•  Moisture sensitive substrates are a problem

EIFS & Rain Control: Recent lessons on how to fail

Kitchener, ON Grand Rapids, MI

Rain Control

Straube Charleston Building Enclosure Council 20101022 21 of 24

Building Science 2008 Joseph Lstiburek – Rain Control 85

J. Straube 2002 86

EIFS

Building Science Rain Control 87

Building Science 2008 Joseph Lstiburek – Rain Control 88

Rain Control

Straube Charleston Building Enclosure Council 20101022 22 of 24

Building Science 2008 Joseph Lstiburek – Rain Control 89

Building Science

Building Science 2008 Joseph Lstiburek – Rain Control 91

Building Science 2008 Joseph Lstiburek – Rain Control 92

Rain Control

Straube Charleston Building Enclosure Council 20101022 23 of 24

Building Science 2008 Joseph Lstiburek – Rain Control 93

Building Science – Rain Control 94

Conclusions

•  Drainage is the key, cladding leaks •  All penetrations need to be drained! •  Beware flashing, it needs to waterproof •  Understand older systems are different

Building Science 95

Rain Control

Straube Charleston Building Enclosure Council 20101022 24 of 24