Presentation on theme: "Obviously, water resistance is the main attribute. However, flashing should also be: Durable and resistant to damage during installation. Resistant to."— Presentation transcript:
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 Facts Flashings must possess certain physical properties.
SHEET METALSADVANTAGESDISADVANTAGES Stainless SteelDurable, Impervious, HardDifficult to bend High installation costs Must be preformed at factory Not easily field-adapted Usually requires steel workers for installation Cold-rolled Copper,Durable, flexible, impervious,Cold-rolled stains surfaces Lead-coated Coppereasier to form and solder thanwhere water runs off; damaged stainless; Lead-coated doesby excessive flexing; Copper not staincorrodes and leads to gradual change in surface color COST: $ $ PER SQ. FT Flashing Comparisons
COMPOSITESADVANTAGESDISADVANTAGES Copper LaminationsEasier to form and joinMore easily torn than metal, than metals.asphalt degrades in sunlight and can ooze under extreme heat COST: $ $ 8.00 PER SQ. FT Flashing Comparisons
TYPEADVANTAGESDISADVANTAGES EPDMNot susceptible to UV rays,Requires adhesives to bond to substrate Corrosion resistant, Goodand requires double sided tape to seal laps, Tear and puncture resistance More difficult to work with than rubberized asphalt, resulting in higher labor costs RubberizedFlexible at low temperaturesAffected by UV rays Asphalt FlashingExcellent tear/punctureCannot form 45 degree drip edge System resistance; self seals aroundLoses adhesive properties below 40 degrees stainless steel drip edge;Rubberized-asphalt component can ooze easy to installout to the exterior of the building in warm temperatures. COST: $ $ 5.00 PER SQ. FT (including drip edge) COST: $ $ 5.00 PER SQ. FT TYPEADVANTAGESDISADVANTAGES Elvaloy ® MembraneFlexible 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 will repel most chemicals Compatible with most silicone and urethane sealants. Suitable for thru-wall or surface- mount construction. *Elvaloy® is a registered trademark of the DuPont Company COST: $ $ 6.00 PER SQ. FT (with drip edge) $ $ 5.00 PER SQ. FT (without drip edge)
Stainless Steel and Copper Flashing Accessories OUTSIDE CORNER INSIDE CORNER END DAM
Flashing Locations AT SHELF ANGLES AT SILLS OVER OPENINGS AT ROOF/WALL INTERSECTIONS 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 BARRIERS There 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
DETAILING AIR/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.
INSTALLATION KEYS 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 COMPATIBILITY KEYS 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?
CONTRACTORS INSTALLATION 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.
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 p: f: e: CHRIS BUPP p: