Spray Foam Installations. How to make it work for YOU. Topics of this session. What is spray foam Building science as it relates to spray foam Different types of spray foam Applications. ISO “A” Side. RESIN “B” Side. What is spray foam. Polyols Surfactants Blowing Agents
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Spray Foam Installations How to make it work for YOU
Topics of this session • What is spray foam • Building science as it relates to spray foam • Different types of spray foam • Applications
ISO “A” Side RESIN “B” Side What is spray foam Polyols Surfactants Blowing Agents Flame Retardents Catalysts Etc. 100% Isocyanate All foams are NOT the same. The material selections on the B side make foam systems very different.
What is spray foam • Insulation and air barrier in one material • Vapour retarder, sometimes • Cellular plastic insulation
How is Spray Foam Installed • Spray foam truck arrives on schedule, when promised • Two liquid components, mixed under pressure at the tip of a spray gun • When mixed, expands 30-100 times in seconds and sets within 30 seconds • Excess trimmed and removed
Why use spray foam • 1) Problem solver • Spray and go away • Reduce risk, liability and warranty issues • 2) Build better buildings • -more energy efficient • -better indoor air quality • -consumers are demanding it
Building Science 101 As it relates to Spray foam
Hot Side 2 in 1 in Staple Fiberglass Screening Cardboard stapled to stud Cold side Crimping at the corners of the stud cavity Perfect fit • A Canadian government study showed that “crimping” batt insulation (compressing the insulation at the corners) averaging 6% of the cross section of the stud space causes a 20% – 35% drop in thermal resistance of the wall.
Controlling Air Leakage • Most building envelope problems are a result of failed air barriers • Moisture travels as airborne water vapour until it hits a “condensing plane” such as the exterior sheathing in a wall assembly or rim joist • With foam, the air barrier is contiguous throughout the wall assembly
Air Barriersmust have the following characteristics • Be impermeable to air movement • Be continuous-seal the entire building • Be durable –able to withstand changing pressures (wind) • Be buildable-easy to install and maintain
The 4 qualifications required for air barriers are extremely rigid: Any material or system that fails in any of these is NOT an effective air barrier. • Meeting all 4 objectives is extremely difficult with conventional materials and often impossible in modern buildings: • Industry concern: that common air barriers are often the victim of subtrades that operate after the air barrier is installed.
Moisture movement • Moisture moves through building assemblies by two mechanisms: Air Leakage Vapor Diffusion • Air leakage may occur anytime there is a difference in air pressure on either sides of material • Vapor has a natural tendency to move from areas of high concentration to areas of low concentration. • Generally from warm to cold Which is the more damaging mechanism?
This test was first done in the 1980’s by CMHC… Canada Mortgage & Housing Corp – cmhc-schl.gc.ca
What’s the message here? • AIR LEAKAGE is your biggest problem • -not inadequate insulation • -not vapour barrier • Ineffective or compromised air barriers create most problems associated with building envelopes in our climate
Generic foam types ½ Pound foams 2 Pound foams
Generic Foam Types • Can be generally divided into two types • ½ lb foams • 2 lb foams
Generic foam types • Similarities • Chemical composition • Air sealing characteristics • Thermal barriers • Safety and health during application • Exothermic reaction creates foam • Very technical installation
Cell Structure ½ Pound foams Two pound foams Closed cell Contain gasses trapped in the closed cell structure Cells created by a chemical blowing agent • Open cells • Contain air • Reaction of water in the polyol with the MDI
Thermal Resistance (R Value) ½ Pound foams Two pound foams Trapped gasses create thermal resistance Initial R Value is R7.5/inch aged R Value - declines over time to R6/inch due to cell gasses near surface escaping. • Trapped air creates thermal resistance • R value typically R3.6-3.8/inch
VapourPermeance ½ Pound foams Two pound foams Considered a vapour barrier at certain thickness Depends on substrate Code officials may require vapour protection for framing • Not a vapour barrier • Considered a breathable foam system • Has drying potential • requires separate vapour barrier, when required • Other building components may act as vapour barrier (ie: OSB floor in bonus rooms)
Installation ½ pound foams Two pound foams Usually not trimmed, requires special scarfing tool Adhesion to substrate critical Typically sprayed max 2” thick per pass Must let the heat dissipate from foam before next pass, or else…. • Typically sprayed in one pass at any thickness • Easily trimmed with handsaw
2 LB foam sprayed too thick Too thick = -elongated cells -weak cells
Water Absorbtion ASTM-D2842 ½ pound foams Two pound foams Resists water penetration Absorbtion generally less than 4% Will provide additional rain/moisture control on outside of buildings • Liquid water can be forced in under pressure. • Typically drains through or dries • Absorbtion varies by Mfr. from 4% to 47% • Check the Data sheet or CCMC report
How “green” is my foam? ½ pound foam Two pound foam Recycled content +/- Ozone depleting substances (ODS) being phased out New 245 blowing agent is a greenhouse gas, GWP = 950 • Recycled content +/- • Waterblown • Carbon dioxide from reaction, GWP = 1
When should you use 2 lb foam • When you have a limited cavity size and need the extra R Value • When you have compressive strength requirements • exterior basements • Unidirectional and extreme vapour drive • Cold storage, freezers
Which foam is right for you? ½ pound foam Two pound foam Vapour barrier Higher R per inch • More economical • Less enviro impact Use the more affordable ½ pound foam unless there are specific reasons to use 2 pound foam Because if foam is more economical, people will be more inclined to use it
Where, when, why and how Applications
Accommodating Complex Construction Windows Metal Stud Channels Wide stud spaces
Rim joist assemblies • Major source of air infiltration • Extremely difficult to air seal with poly and sealant around penetrations • What are the long term implications of the engineered joists getting wet? • This is what is holding your house up
Rim joist assemblies IMPORTANT: seal to the top plate of the frost wall
Bonus rooms • Eliminate the need for “hot boxes” • No need to heat space below floor • No drop framing • Virtually a trade off economically for a much superior system (compared to a “hot box”)
Bonus rooms • Floor temp will typically be within 2 deg. of room temp • Contact with heating ducts is a code issue but specific testing can be done by mfr. to satisfy code officials. • This testing is specific to each manufacturer’s product
Spray foam vs hotbox method: • -no frost blooms on garage walls from conditioned air being pushed outside the building envelope • -no condensation dripping from screws on garage ceiling • -no worries about carbon monoxide getting into living space • -no cold floor/cold room complaints • -no frozen pipes(make sure adequate foam coverage)
When spraying bonus rooms • Plumbing and ducts tight to subfloor • Make sure adequate foam coverage over plumbing runs • “tenting” around plumbing with cardboard may be required.
Basements • Huge amounts of moisture coming out of new concrete • We’re sealing them up wet, should we? • Large potential liability for builders
Moisture from construction Several thousand pounds of water from freshly placed concrete attempt to dry inwards.