The Differences Between
 High-Density   &    Low-Density
 Spray Polyurethane Foam


Closed Cell Foam

R-6.5 per inch
Stable R-Value
Minimizes Conduction
Prevents Air Infiltration
Air Intrusion-Doesn't affect performance
Reduces Radiant Heat Gain
Excellent Vapor Retardant
Prevents Moisture Drive
Rigid & Strong- Increases Racking strength of building
Commercial Roofing Material
Does Not Absorb Water!!

High-Density Foam- This product puts you in full control of your temperature & humidity in your environment. It can be used in many applications for a variety of different intentions.  It works just as well in the summer as it does in the winter going far beyond just insulation.

CONS 
Can air seal a Structure too much
- this is measured using a Blower Door Test and corrected if necessary.

Open Cell Foam

R-3.5 per inch
Stable R-Value
Minimizes Conduction
Stops Convection Loops
Prevents Air Infiltration
Air Intrusion- Doesn't affect performance
Reduces Radiant Heat Gain
Excellent Soundproofing Quality

Low-Density Foam- is also an impressive insulation choice.  When used properly it can be exceedingly effective.  Its only real fault is that it will allow moisture to pass through it and absorb it in the process.  You will need to consider this during the design phase.  If moisture can pass through your insulation it could potentially be trapped on the other side.  This has to be considered if spraying to a roof deck or to exterior walls.  If not vented properly it is possible that the low-density foam could create a build-up of moisture on the plywood leading to mold and mildew problems.  When insulating below grade, low-density foam is absolutely not an option to consider due to this very problem 

CONS

 -Lacks High-Density Strength
-Can air seal a Structure too much this is measured using a
Blower Door Test and corrected if necessary
-Not a Vapor Retardant
-Will NOT Stop Moisture Drive- Moisture moves through it
-Absorbs Water / Saturating Foam