Obviously, water resistance is the main attribute. However, flashing should also be: •Durable and resistant to damage during installation. •Resistant to puncturing or tearing.•Easily formed into desired shapes. Other Considerations:•Resistance to ultraviolet light must be evaluated during flashing selection. •Flashing material should not be susceptible to corrosion in fresh mortar or react with other adjacent materials such as rigid insulation. •Compatibility with materials such as sealants or adhesives must be reviewed. •The minimum expected life of the the flashing materials should be the anticipated life of the structure

Flashing FactsFlashings must possess certain physical properties.

Flashing “Install-ability”

SHEET METALS ADVANTAGES DISADVANTAGES

Stainless Steel Durable, Impervious, Hard Difficult to bend High installation costs Must be preformed at factoryNot easily field-adaptedUsually requires steelworkers for installation

Cold-rolled Copper, Durable, flexible, impervious, Cold-rolled stains surfacesLead-coated Copper easier to form and solder than where water runs off; damaged

stainless; Lead-coated does by excessive flexing; Copper not stain corrodes and leads to gradual

change in surface color

COST: $ 10.00 -$ 12.00 PER SQ. FT

COST: $ 10.00 - $ 12.00 PER SQ. FT

Flashing Comparisons

COMPOSITES ADVANTAGES DISADVANTAGESCopper Laminations Easier to form and join More easily torn than metal, than metals. asphalt degrades in sunlight and can ooze under extreme heat

COST: $ 7.00 -$ 8.00 PER SQ. FT

Flashing Comparisons

Flashing Comparisons

TYPE ADVANTAGES DISADVANTAGES

EPDM Not susceptible to UV rays, Requires adhesives to bond to substrate Corrosion resistant, Good and requires double sided tape to seal laps, Tear and puncture resistance More difficult to work with than rubberized

asphalt, resulting in higher labor costs

Rubberized Flexible at low temperatures Affected by UV rays Asphalt Flashing Excellent tear/puncture Cannot form 45 degree drip edge System resistance; self seals around Loses adhesive properties below 40 degrees

stainless steel drip edge; Rubberized-asphalt component can ooze easy to install out to the exterior of the building in warm

temperatures.COST: $ 4.00 - $ 5.00 PER SQ. FT (including drip edge)

COST: $ 4.00 - $ 5.00 PER SQ. FT

TYPE ADVANTAGES DISADVANTAGES

Elvaloy® Membrane Flexible at low temperatures. N/A Not susceptible to UV.

Self-adhesive, easy to install,

seamless preformed corners and end dams available.Extremely tough: excellent impact and tear/puncture resistance. Highly resistant to oils and willrepel most chemicalsCompatible with most silicone and urethane sealants. Suitable for thru-wall or surface-mount construction.

*Elvaloy® is a registered trademark of the DuPont Company

COST: $ 5.00 - $ 6.00 PER SQ. FT (with drip edge)$ 4.00 - $ 5.00 PER SQ. FT (without drip edge)

Flashing “DROOL”

Stainless Steel and Copper Flashing Accessories

OUTSIDE CORNER

INSIDE CORNER

END DAM

Flashing Locations

AT SHELF ANGLES AT SILLS

OVER OPENINGS

AT ROOF/WALLINTERSECTIONS

UNDER COPINGS

AT WALL BASE

Recommended to ensure that the top edge of the flashing will remain attached to the back-up

Termination Bar

Sealant

Term Bar

Foam Seal

Flashing

Used at the top of flashing to mechanically secure to back-up wall.

•Type 304 Stainless Steel

•9/32” holes spaced 8” o.c.

•Size 1/8” x 1” x 96”

Drip Plates• Drip Plates are recommended

by the BIA for flashings that cannot be exposed to UV

• Meets BIA requirements of extending ¼” beyond face of wall forming a drip.

• Available in stainless steel and copper.

*Compatible with Clear Adhesive Flashings ONLY

Flash-Adhere Strip (w/release paper) for precise and permanent placement of flashing

Compressible filler adhered to the bottom of drip plate acts as a bond break and helps prevent air and moisture infiltration.

Mortar Collection Device

Must suspend mortar at two distinct heights

• Plastic Tubes – 16” OC

• Cotton Cords/Wicks – 16” OC

• Honeycomb Plastic – 24” OC

• Aluminum Vent – 24” OC

• Synthetic Mesh – 24” OC

• Open Head Joint – 24” OC

Vents at the top of the cavity can dramatically increase air ventilation to improve drainage.

*Compatible with Clear Adhesive Flashings ONLY

Weeps and Vents

Weep vents allow for proper drainage and ventilation helping to keep wall cavities dry and clear of debris

DEFINING AIR BARRIERS vs. VAPOR BARRIERSThere are two ways for moisture to infiltrate the building envelope.

1.Diffuse flow is a gaseous vapor that passes through all materials.

2.Channel flow is a more serious concern, resulting from breaches in the building envelope. Channel Flow

Diffuse Flow

DEFINING AIR BARRIERS vs. VAPOR BARRIERS

An air barrier MUST resist air leakage or channel flow at all pressure levels through the wall assembly.

A vapor barrier MUST resist the movement of vapor through diffusion.

NOT ALL AIR BARRIERS ARE VAPOR BARRIERS Channel Flow

Diffuse Flow

DEFINING AIR BARRIERS vs. VAPOR BARRIERS

Air barriers or permeable membranes allow the wall to “breathe” and offer designers more flexibility in their placement within the wall assembly.

The ability to make the barrier system totally continuous should be the main criteria for the location. Channel Flow

Diffuse Flow

DEFINING AIR BARRIERS vs. VAPOR BARRIERS

Vapor barriers or non-permeable membranes have a specific location within the wall.

Vapor barriers MUST be completely continuous to properly perform their function.

Channel Flow

Diffuse Flow

DETAILINGAIR/VAPOR BARRIER INTEGRATION

Intersections of different

materials, expansion

joints, elevation changes,

inside & outside corners,

and door & window

openings are some

areas/situations that

require detailing in an

air/vapor barrier system.

INSTALLATIONKEYS TO A SUCCESSFUL AIR/VAPOR BARRIER

The detail between an

air/vapor barrier and the

roofing system is critical.

CONTINUITY WITH THE ROOFING SYSTEM

ANCHORING SYSTEM COMPATIBILITYKEYS TO A SUCCESSFUL AIR/VAPOR BARRIER

Does the anchoring system

protect the integrity of the

air/vapor barrier and does the

air/vapor barrier seal around the

anchoring system?

COMPARISONLIQUID VS. SHEET MATERIALS

Wall System Liquid SheetSteel/Sheathing ✔ ✔

Concrete/ICF ✔ ✔CMU ✔ ✖

CONTRACTORSINSTALLATION AND EDUCATION

Be sure to use a company with

personnel trained/certified for

installing air barrier systems.

A pre-installation jobsite meeting

is recommended to go over

specific project requirements.

COMPATIBILITY

Building Envelope Summary Flashings must work as a system and include all

components such as termination bar, drip plates, mortar collection device, weeps/vents, etc.

User-friendly flashing systems for field personnel are important

Air/Vapor barriers MUST be totally continuous and be able to tie into adjacent building components via proper detailing.

Breathable vs. Non-breathable?

HOHMANN AND BARNARD, INC.30 RASONS CT. HAUPPAUGE, NY 11788

p: 800-645-0616f: 631-234-0683e: weanchor@h-b.com

www.h-b.com

CHRIS BUPPp: 717-779-4943chrisb@h-b.com