Water Mgmt : Flashing
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Transcript of Water Mgmt : Flashing
August 24, 2006Eppstein Uhen Architects 1
Water Management F L A S H I N G
p r e s e n t a t i o n
August 24, 2006Eppstein Uhen Architects 2
Presentation OutlineI. Water Management System (WMS)
A. Nature of WaterB. WMS Components
II. Exterior Shell PerformanceA. RoofingB. Walls
III. WMS Focus: FlashingA. Flashing TypesB. Roof FlashingC. Wall Flashing
IV. Conclusions
August 24, 2006Eppstein Uhen Architects 3
Water Management SYSTEM
I. Water Issue? A. Knee jerk reaction: Blame the FLASHING
II. While researching FLASHING, other WMS components always mentioned:
A. Air and Vapor Barriers B. Heat Barrier C. Water Barrier
August 24, 2006Eppstein Uhen Architects 4
Water Management SYSTEMI. WMS Presentations
A. Part I: Flashing (PM Workshop)
B. Part II: Water Barriers (PM Workshop)
C. Part III: Air/Vapor/Heat Barriers (PM Workshop)
D. Part IV: WMS Detailing (Studio Workshops)i. Masonry Wallsii. Veneer Systemsiii. Wood Construction
August 24, 2006Eppstein Uhen Architects 5
WMS: Nature of Water
I. (3) Physical States of H20A. Liquid (water) B. Vapor (gas)C. Solid (ice)
II. Sources of MoistureA. Liquid/Solid:
i. Precipitation (Rain, Sleet, Snow)ii. Condensation
B. Vapor: i. Artificial Humidificationii. Relative Humidity
August 24, 2006Eppstein Uhen Architects 6
WMS: Nature of WaterI. Driving Forces for Rainwater Penetrations
A. Gravityi. Draw water down thru openings into assembly
B. Surface TensionC. Capillary Suction
i. Sucks water thru cracks/poresD. Momentum
i. Pass thru openings in exterior claddingE. Air Pressure Differential
i. Push/pull water thru cracks/pores
August 24, 2006Eppstein Uhen Architects 7
WMS: Components
I. Air and Vapor Barriers
II. Heat Barrier
III. Flashing
IV. Water Barrier
August 24, 2006Eppstein Uhen Architects 8
WMS: Air & Vapor Barriers (AVB)
I. Most materials are effective AIR Barriers
i. Needs to be continuousa. Intersections between wall/roof, floors, foundationb. Interface of wall assembly & door/window/curtain wallsc. Penetrations thru ABd. Joints/seams between sheets/boards of AB
II. Few materials are complete VAPOR Barriers
i. Place on warm side (winter) of Heat Barrier (insulation)a. Vapor arrested before it reaches colder surfacesb. Moist, warm air moves TO cooler, dryer air
III. More accurate description: Vapor Retarders
August 24, 2006Eppstein Uhen Architects 9
WMS: Components
I. Air and Vapor Barriers
II. Heat Barrier
III. Flashing
IV. Water Barrier
August 24, 2006Eppstein Uhen Architects 10
WMS: Heat Barrier (Insulation)
I. Heat TransferA. Decrease as the wall’s thermal
resistance increases
II. R-Value: thermal resistance
III. Common pitfallsA. Inappropriate locationB. Discontinuity
i. Thermal bridgingC. Dewpoint
i. Condensation & staining issues
August 24, 2006Eppstein Uhen Architects 11
WMS: Components
I. Air and Vapor Barriers
II. Heat Barrier
III. Flashing
IV. Water Barrier
August 24, 2006Eppstein Uhen Architects 12
WMS: Flashing
I. Main Causes of Moisture Intrusions
A. Interface detailsi. Bldg envelope penetrations
a. Decksb. Windowsc. Doors
B. Flashingi. Did not exist OR were not integrated
with the rest of the WMS
August 24, 2006Eppstein Uhen Architects 13
WMS: Components
I. Air and Vapor Barriers
II. Heat Barrier
III. Flashing
IV. Water Barrier
August 24, 2006Eppstein Uhen Architects 14
WMS: Water Barrier (WB)I. Forms vertical surface behind cladding
A. Allows water to drain out of the wall system
II. Exterior cladding protects WBA. WeatherB. Ultraviolet (UV) Radiation
III. Lets wall components dry safetyA. Allows internal vapor to escape out
IV. Most important deterrent against liquid water penetrating INTO the bldg enclosure
A. Acts as a barricade - Continuous & shingled
August 24, 2006Eppstein Uhen Architects 15
WMS: ComponentsI. Map out the PASSAGE of water
A. Drainage Spacei. Allows free drainage of water
B. Drainage Planei. Water Barrier (WRB)
a. Overlappingb. Integrating w/flashing
C. Flashings
D. Weep Holesi. Located DIRECTLY above flashing
August 24, 2006Eppstein Uhen Architects 16
Exterior Shell Performance
I. Continual expansion & contractionA. Moisture content + Thermal
II. Corrosion: Metals A. Electrolytic action causes a current to flowB. Water is the electrolyte to complete the circuitC. Electronic potential:
i. Metal A + Metal Bii. Metal A + Water + Salt
D. Example: Storing planes in the desert
III. Decay: WoodA. Food (wood) + water + air+ temperatureB. Example: Submerged trees in water
IV. Efflorescence: MasonryA. Migrating water dissolves salts inside material and deposits them
on it’s surface
V. Leaching: Concrete & MortarA. Leaching out the calcium from the calcium chloride
August 24, 2006Eppstein Uhen Architects 17
Exterior Shell Performance
I. (3) Types of Exterior Wall Design
A. Face-Sealed Barriersi. EIFS (non-drainable)ii. Curtain Walls (face-sealed)
B. Concealed Barrier Wallsi. Stucco system (drainable)ii. EIFS (drainable)
C. Drain Cavity or Rain Screeni. Brick-veneer cavity wallsii. Furred-out clapboard wallsiii. EIFS (drainable w/membrane)
August 24, 2006Eppstein Uhen Architects 18
Exterior Shell PerformanceI. Face-Sealed Barriers
A. Every seam/crack is sealedB. Requires detailed workmanshipC. Requires continuous
maintenanceD. Most vulnerable to rain
infiltrationE. Effective in areas with:
i. Low wind and low rain exposure
August 24, 2006Eppstein Uhen Architects 19
Exterior Shell Performance
I. Concealed Barrier WallsA. Relies on multiple layers for rain penetrationB. Provides (2) lines of defenseC. Drainage plane in the wall assembly
i. Usually a water-resistive barrier membraneD. Requires continuous maintenanceE. Effective in areas with:
i. Moderate wind and moderate rain exposure
August 24, 2006Eppstein Uhen Architects 20
Exterior Shell Performance
I. Drain Cavity or Rain ScreenA. Relies on (2) layers + drained cavity for rain penetrationB. Provides (2) lines of defenseC. Drainage plane in the wall assembly
i. Usually a water-resistive barrier membraneD. Additional features:
i. Capillary break between porous materialsii. Freer drainageiii. Venting limits relative humidity (RH) outboard of sheathing
E. Effective in areas with:i. High wind and high rain exposure
August 24, 2006Eppstein Uhen Architects 21
Exterior Shell Performance
I. Drainage Wall System
August 24, 2006Eppstein Uhen Architects 22
Exterior Shell Performance
I. Enclosure Performance depends on:
A. Proper Sequencingi. Exposure Duration
B. Detailingi. Spec vs. Drawingsii. Field vs. Pre-fab
C. Construction Material’s Recoveryi. Ability to get wet and then dry outii. Not deteriorate or contaminate (microbes)
August 24, 2006Eppstein Uhen Architects 23
Flashing - TypesI. Sheet Metals
A. Stainless SteelB. Galvanized SteelC. Copper (Cold Rolled)D. Copper (Lead-Coated)E. Aluminum
II. Composite MaterialsA. Copper LaminatesB. Aluminum LaminatesC. Lead Laminates
III. FabricsA. PVCB. Rubberized AsphaltC. EPDM
August 24, 2006Eppstein Uhen Architects 24
Flashing – Sheet MetalsI. Advantages
A. Extend beyond face of wall i. Forms drip edge – conducts water out
B. May be solderedi. Mastics or sealants need not be solely relied upon
C. Stiffness allows for proper geometriesD. Can be exposed to weatherE. Suitable substrate for construction sealants
II. DisadvantagesA. More expensive than membrane flashingB. Aluminum corrodes in an alkaline environment
i. Masonry Mortar ii. Concrete
August 24, 2006Eppstein Uhen Architects 25
Flashing – Composite/Fabrics
I. AdvantagesA. Less expensive than metal flashingB. Self-sealing properties
II. DisadvantagesA. Must be continuously supported
i. To avoid creating water pocketsii. To provide a solid substance for proper seaming
B. Relies on field installeri. Bed & seal membrane (transverse seams)ii. Unsuitable substrate for common construction sealants
C. Exposure issues: degradation due to sunlighti. Must terminate at/inboard of wall faceii. This encourages water bypass at front edge of membrane
August 24, 2006Eppstein Uhen Architects 26
Flashing – ConsiderationsI. Main Criterion: Expected Life
A. Flashing MUST last as long as life of building
II. CostA. Material CostB. Installation CostC. Maintenance Cost
III. InstallationA. Ease of InstallationB. Ease to JoinC. Ease of Fabrication
IV. PerformanceA. Compatibility with materialsB. Resistance to punctures/tearsC. Resistance to UVD. Resistance to Corrosion
Flashing with Metal Drip Edge
August 24, 2006Eppstein Uhen Architects 27
Flashing – ComparisonS
tain
less
Ste
el
Gal
vani
zed
Ste
el
Cop
per (
Col
d R
olle
d)
Cop
per (
Lead
-Coa
ted)
Alu
min
um
Cop
per L
amin
ates
Alu
min
um L
amin
ates
Lead
Lam
inat
es
PV
C
Rub
beriz
ed A
spha
lt
EP
DM
THICKNESS (MIN) 0.01" 0.015" 10 oz/ft210 oz/ft2 X 5 oz/ft2 ? ? 30 mils 30 mils 30 mils
A) COSTMaterial Cost 2 2 1 1 2 2 3 3 5 5 4Installation CostMaintenance Cost
A) Subtotal 2.0 2.0 1.0 1.0 2.0 2.0 3.0 3.0 5.0 5.0 4.0RATINGS
0: Not Applicable1: Very High2: High3: Average4: Low5: Very Low
B) INSTALLATIONEase of Installation 1 2 2 2 3 4 4 4 5 5 5Ease to Join 1 1 3 2 2 3 3 3 4 5 4Ease of Fabrication 2 1 3 2 2 3 3 3 4 4 4
B) Subtotal 1.3 1.3 2.7 2.0 2.3 3.3 3.3 3.3 4.3 4.7 4.3RATINGS
0: Not Applicable1: Very Difficult2: Difficult3: Average4: Easy5: Very Easy
C) PERFORMANCECompatibility with materials 3 3 2 2 2 2 2 2 1 2 2Resistance to punctures/tears 4 5 3 3 4 2 3 3 1 2 2Resistance to UV 5 5 5 5 5 3 3 3 1 2 3Resistance to Corrosion 5 3 4 4 5 3 3 3 4 4 4Expected Life 4 4 5 5 4 3 3 3 2 4 4
C) Subtotal 4.2 4.0 3.8 3.8 4.0 2.6 2.8 2.8 1.8 2.8 3.0RATINGS
0: Not Applicable1: Very Poor2: Poor3: Average4: Good5: Very Good
COMMENTS1. Corrodes in fresh mortar ?2. Non-staining ? ? ? ? ? ? ? ?3. Requires metal drip edge ? ? ? ?4. Self-sealing if puntured ?5. Full-support required ? ? ?
TOTAL (1:Low 5:High) 2.5 2.4 2.5 2.3 2.8 2.6 3.0 3.0 3.7 4.2 3.8
SHEET METALS COMPOSITE MATERIALS FABRICS
DESCRIPTION
Sta
inle
ss S
teel
Gal
vani
zed
Ste
el
Cop
per (
Col
d R
olle
d)
Cop
per (
Lead
-Coa
ted)
Alu
min
um
Cop
per L
amin
ates
Alu
min
um L
amin
ates
Lead
Lam
inat
es
PV
C
Rub
beriz
ed A
spha
lt
EP
DM
THICKNESS (MIN) 0.01" 0.015" 10 oz/ft210 oz/ft2 X 5 oz/ft2 ? ? 30 mils 30 mils 30 mils
A) COSTMaterial Cost 2 2 1 1 2 2 3 3 5 5 4Installation CostMaintenance Cost
A) Subtotal 2.0 2.0 1.0 1.0 2.0 2.0 3.0 3.0 5.0 5.0 4.0
SHEET METALS COMPOSITE MATERIALS FABRICS
DESCRIPTION
Sta
inle
ss S
teel
Gal
vani
zed
Ste
el
Cop
per (
Col
d R
olle
d)
Cop
per (
Lead
-Coa
ted)
Alu
min
um
Cop
per L
amin
ates
Alu
min
um L
amin
ates
Lead
Lam
inat
es
PV
C
Rub
beriz
ed A
spha
lt
EP
DM
B) INSTALLATIONEase of Installation 1 2 2 2 3 4 4 4 5 5 5Ease to Join 1 1 3 2 2 3 3 3 4 5 4Ease of Fabrication 2 1 3 2 2 3 3 3 4 4 4
B) Subtotal 1.3 1.3 2.7 2.0 2.3 3.3 3.3 3.3 4.3 4.7 4.3
SHEET METALS COMPOSITE MATERIALS FABRICS
DESCRIPTION
Sta
inle
ss S
teel
Gal
vani
zed
Ste
el
Cop
per (
Col
d R
olle
d)
Cop
per (
Lead
-Coa
ted)
Alu
min
um
Cop
per L
amin
ates
Alu
min
um L
amin
ates
Lead
Lam
inat
es
PV
C
Rub
beriz
ed A
spha
lt
EP
DM
C) PERFORMANCECompatibility with materials 3 3 2 2 2 2 2 2 1 2 2Resistance to punctures/tears 4 5 3 3 4 2 3 3 1 2 2Resistance to UV 5 5 5 5 5 3 3 3 1 2 3Resistance to Corrosion 5 3 4 4 5 3 3 3 4 4 4Expected Life 4 4 5 5 4 3 3 3 2 4 4
C) Subtotal 4.2 4.0 3.8 3.8 4.0 2.6 2.8 2.8 1.8 2.8 3.0
SHEET METALS COMPOSITE MATERIALS FABRICS
DESCRIPTION
Sta
inle
ss S
teel
Gal
vani
zed
Ste
el
Cop
per (
Col
d R
olle
d)
Cop
per (
Lead
-Coa
ted)
Alu
min
um
Cop
per L
amin
ates
Alu
min
um L
amin
ates
Lead
Lam
inat
es
PV
C
Rub
beriz
ed A
spha
lt
EP
DM
TOTAL (1:Low 5:High) 2.5 2.4 2.5 2.3 2.8 2.6 3.0 3.0 3.7 4.2 3.8
SHEET METALS COMPOSITE MATERIALS FABRICS
DESCRIPTION
August 24, 2006Eppstein Uhen Architects 28
WMS: Flashing – Where?I. Where Water Barriers (WB) terminateII. B30 Roofing
A. B3010 Roof CoveringsB. B3020 Roof Openings
III. B20 Exterior ClosureA. B2010 Exterior Walls
i. Top of exterior walls & parapetsii. Base of exterior wallsiii. Penetrations through the wall assemblyiv. Shelf angles (cavity walls)
IV. B2020 Exterior Windows / B2030 Exterior Doors
i. Perimeters of openings: Head, Sill, & JambV. A10 Foundations (exposed)
August 24, 2006Eppstein Uhen Architects 29
Flashing: Roofing – Where?
I. TerminationsA. Expansion joints
II. JunctionsA. Examples:
i. Penthousesii. Skylightsiii. Chimneysiv. Equipment Housingv. Parapets
B. Thru-wall needs to lead water out of the wall
C. Parapets: exposed on exterior, interior and top
August 24, 2006Eppstein Uhen Architects 30
Flashing: Roofing – Where?
III. PenetrationsA. Examples: pipes, ductsB. Group many into a single curbC. Differential movementD. If connected- flashing flexible
to move with itE. Minimize quantityF. Small pipes/ducts
i. Separate support for base flashing not used
ii. Sleeves (metal or plastic flanged): require frequent maintenance
iii. Counterflashing + coverIV. Joints
August 24, 2006Eppstein Uhen Architects 31
Flashing: RoofingI. Prevents water from penetrating exterior
surfaceA. Intercepts water at parapets, walls, penetrationsB. Diverts itC. Leads it out to the membraneD. Flows out to the roof drains
II. Think of roof membrane as one large flashing designed to hold water until drainage system takes over
III. Detail ComponentsA. Base flashingB. Counter-flashingC. Cap flashing
Concrete Roof Slab Dtl
August 24, 2006Eppstein Uhen Architects 32
Base Flashing (Roofing)I. Extension of the roof
membrane or a different material bonded to form a waterproof joint
II. Extends upward along vertical surface
III. Diverts water onto the membrane
IV. Pass over top of parapet or cant
A. Minimize of water leaking behind it
B. Liquid-applied: not suitablei. Cannot be carried over a
parapet/roof-wall jointC. Reach higher than water
could be “stored”
August 24, 2006Eppstein Uhen Architects 33
Counter-Flashing (Roof)I. Description
A. Carries water onto base flashing/membraneB. Covers vertical face of base flashingC. Secured to the parapet or wall claddingD. Not connected to base flashingE. Provides physical and UV protection for base
flashing F. Not expected to watertight
II. May not be required with some roofing types:
A. Modified bitumenB. Single-ply membranes
III. If not required, don’t include it A. Covers up defects & hinders maintenance
IV. Details requiring reglets should be avoided
August 24, 2006Eppstein Uhen Architects 34
Cap Flashing (Roof)I. Horizontal coverings for
parapets & expansion jointsII. Sloped toward roofIII. Secured to allow
differential movementIV. Not expected to watertightV. Provides physical and UV
protection for base flashingVI. Only aesthetic with some
roofing types:A. Modified asphaltB. Single-ply membranes
August 24, 2006Eppstein Uhen Architects 35
Cap Flashing (Roof)
August 24, 2006Eppstein Uhen Architects 36
Roof Flashing - SummaryI. Compatibility between base flashing & the
membraneII. Ease of right angle turns in built-up roofs
A. Cants prevents puncturing of flashing membranes
III. Differential movementA. Counterflashing and wall/parapet it is securedB. Roof deck and wall/parapet
IV. Failure of reglet sealsA. Caulk not maintainedB. Counterflashing moves
August 24, 2006Eppstein Uhen Architects 37
Flashing: Walls – Where?I. Critical Locations
A. Top of the Walli. Parapet
B. Openingsi. Headii. Silliii. Jamb
C. Through Walli. Shelf Angles
D. Base of Walli. Where wall rests on foundation
August 24, 2006Eppstein Uhen Architects 38
Flashing: Openings
August 24, 2006Eppstein Uhen Architects 39
Flashing: Head
Window Head Detail and Cavity Seal
August 24, 2006Eppstein Uhen Architects 40
Flashing: Head
August 24, 2006Eppstein Uhen Architects 41
Flashing: Window Lintel
August 24, 2006Eppstein Uhen Architects 42
Flashing Details - Sills
August 24, 2006Eppstein Uhen Architects 43
Flashing Details - Sills
August 24, 2006Eppstein Uhen Architects 44
Flashing: Window Sill
Commercial aluminum window in metal stud with exterior gypsum board sheathing
August 24, 2006Eppstein Uhen Architects 45
Flashing: Window Sill
August 24, 2006Eppstein Uhen Architects 46
Flashing: Interruptions
Lipped Brick Detail
August 24, 2006Eppstein Uhen Architects 47
Flashing: Base of Wall
August 24, 2006Eppstein Uhen Architects 48
Flashing: Base of Wall
Base flashing with concrete wall backup and masonry veneer
August 24, 2006Eppstein Uhen Architects 49
Flashing: Base of Wall
August 24, 2006Eppstein Uhen Architects 50
Flashing: Base of Wall
August 24, 2006Eppstein Uhen Architects 51
Flashing: Coordination
August 24, 2006Eppstein Uhen Architects 52
Flashing: Critical DetailsI. Critical Details
A. Inner & Outer Cornersi. Field Fabricatedii. Preformed Corners
B. Lapping i. Horizontal – Flashingii. Vertical – Water Barrier
C. Terminations i. Drip Edgesii. End Dams
a. 6”-8” beyond jambD. Keep Air Space (AS) clean
i. Veneer (wood frame): 1” ii. Veneer (steel frame): 2” iii. Cavity (w/rigid insul): 1” iv. Cavity (w/no insul): 2” v. Cavity (w/rigid insul &
drainage panel): 0- 3/8”
August 24, 2006Eppstein Uhen Architects 53
ConclusionI. Water: BAD - Flashing: GOOD
II. Flashing Rules of ThumbA. ContinuityB. Extend past face of wall
i. Divert water OUTC. Seal top of flashing (water barrier)D. Protect flashing from punctures
III. Managing water with a SYSTEMA. Ounce of prevention = Pound of cureB. Initial cost < Future Repair / Liability
August 24, 2006Eppstein Uhen Architects 54
Conclusion
Questions???
Comments???
Concerns???
Suggestions???
August 24, 2006Eppstein Uhen Architects 55
Water Management F L A S H I N G
T H A N K Y O U
August 24, 2006Eppstein Uhen Architects 56
Detailing – Detail on CD’s
August 24, 2006Eppstein Uhen Architects 57
Detailing – Detail on CD’s
August 24, 2006Eppstein Uhen Architects 58
Detailing – Sequencing A
August 24, 2006Eppstein Uhen Architects 59
Detailing – Sequencing B
August 24, 2006Eppstein Uhen Architects 60
Detailing – Sequencing C
August 24, 2006Eppstein Uhen Architects 61
Detailing – Sequencing D
August 24, 2006Eppstein Uhen Architects 62
Detailing – Sequencing E
August 24, 2006Eppstein Uhen Architects 63
Detailing – Sequencing F
August 24, 2006Eppstein Uhen Architects 64
Detailing – Sequencing G
August 24, 2006Eppstein Uhen Architects 65
Detailing – Sequencing H
August 24, 2006Eppstein Uhen Architects 66
Detailing – Sequencing I