Open Cell Spray Foam
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Open Cell Spray Foam Intro to Benefits, Installation and Techniques 2015
Transcript of Open Cell Spray Foam
Open Cell Spray Foam Intro to Benefits, Installation and Techniques
2015
2008 2010 2011
Components
SPF consist of two components, commonly referred to as A and B
§ A-Component is PMDI polymeric methyldiphenyldiisocyanate
§ B-Component is a mixture polyol flame retardants catalysts surfactants blowing agent: water
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Open Cell Basics
§ Approved for construction types: I, II, III, IV, V
§ Light density 0.5 lb.
§ R-value = 3.7 per inch
§ Air impermeable at 3 - 3.5” (See product ESR)
§ Vapor permeable, supports bi-directional drying of assemblies
§ Soft, flexible composition maintains an air seal even after seasonal expansion/contraction of building assembly
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§ Low exothermic reaction temperature; will not harm coatings on electrical wiring, plumbing or other building components
§ Application thickness is not limited
§ Lower cost compared to Closed Cell products
§ 100% water-blown
§ HFC- and PBDE-free
§ Lowest “global warming potential” (GWP of 1)
§ Expands ~100 times from liquid state
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Key Advantages
§ Flexible, maintains an air seal during movement/shifting of the building over time
§ Semi-vapor permeable supports bi-directional drying of assemblies (Mixed Climates)
§ Roof Leak Detection / Gravity Issue
§ 11,000- 21,000 board ft. per set
§ 100:1 Expansion Ratio - (99% air) requires less material, reduced environmental impact, less expensive
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…but
§ Open Cell foam will wick moisture either from a roof leak or excess moisture vapor in the envelope. § If it gets wet... Yank it out and repair.
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Commercial ¡ Faster, easier install in roof decks then closed cell
foam.
¡ One pass application to desired R-value
¡ Convert specs where you can…doesn’t hurt to ask
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Commercial
Open Cell foam air barrier at the top of a wall assembly
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Residential Back outs ¡ Construction Back outs narrow that cost gap ¡ No raised heel trusses
¡ No ridge or soffit vents
¡ Radiant OSB
¡ Sealing to the top plate
¡ Backing knee walls.
¡ Insulating pull down stairs
¡ Reduced HVAC Tonnage
¡ Traditional: 600-700 sq/ft per ton
¡ Foam: 1000-1100 sq/ft per ton
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Residential ¡ Most installs follow the performance path of the
energy code
¡ Section 405, Simulated Performance Alternative allows for reduced R-value if the house meets or exceeds the energy usage of the same house built to code.
¡ Walls 3.5” R-13
¡ Roof 5.5”-6” R-21-22
¡ ACH50 below 2 typical
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Diminishing Returns
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Residential ¡ Most installs follow the performance path of the
energy code
¡ Section 405, Simulated Performance Alternative allows for reduced R-value if the house meets or exceeds the energy usage of the same house built to code.
¡ Walls 3.5” R-13
¡ Roof 5.5”-6” R-21-22
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Residential
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Residential
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Ignition VS Thermal Barriers ¡ Most OC foams are required to be covered by a
5min ignition barrier in attics.
¡ 5 min ignition barriers are required where the area where the foam is installed is accessible for access to mechanical equipment only.
¡ 15 min thermal barriers are required for ALL OC foams where the foam is exposed in a storage area or an area seen as conditioned space. ¡ Flooring = Storage
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Application ¡ Storage at above 50° to maintain optimum yield
¡ Barrel temps at between 90°-100°
¡ Spray temps between 135°- 160°
¡ Picture frame or wet studs
¡ Single pass application in attics and walls.
¡ Easily shaved/ cut back ¡ Make sure that wires and pipes are strapped back
into a stud cavity
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Ventilation, ventilation, ventilation ¡ Ventilate during application. Bring air into the
house and blow air out of the during application
¡ For a retrofit ventilate for the entire reentry time
¡ The nature of spray foam creates a tight envelope. Make sure you advise your client about the need for properly sized ventilation.
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24 hour Reentry time…Every time… No Exceptions
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Application Errors ¡ Improperly maintained equipment
¡ Incorrect Temperatures
¡ Incorrect Pressures
¡ Not following processing parameters. ¡ Poor adhesion
¡ Shrinkage
¡ Pocketing
¡ Off ratio
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Pocketing
Poor adhesion from incorrect spray temperature, or off ratio mix
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Shrinkage
Spraying with material that is too hot will result in this type of application error
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Off ratio
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Common Misconceptions ¡ Open Cell isn’t an air barrier
¡ You need baffles behind the foam
¡ Open Cell foam won’t hold water
¡ Shingle manufacturers won’t warrantee the shingle
¡ Continuously off gasses
¡ Open Cell foam will rot out your roof deck
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“What we’ve got here is failure to communicate . . .” In what is turning out to be an unfortunate turn of phrase the terms “unvented attics” and “unvented roofs” have entered the lexicon. A lot of the blame for that goes to me and for that I am sorry. The “right” terms should have been “conditioned attics” and “conditioned roofs”2.
When we move insulation to the underside of a roof deck3 the space below the insulation is now within the “conditioned space”. This has all kinds of implications…some good…some not so good.
The good implications are that if we locate ductwork and air handlers and sprinklers in the attic space we don’t have to worry about the thermal penalties associated with duct leakage and the moisture penalties associated with induced negative pressures and the durability issues associated with locating equipment in hostile environments and the freezing pipe issues associated with sprinkler systems. …………………..”
Joseph Lstiburek
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Questions?
