1. Fiberglass batts will not stop air leakage. Blown-in cellulose will slow down air leakage. Spray-foam will stop air leakage dead. Spray-foam is also mold and moisture resistant unlike fiberglass and cellulose.
2. Fiberglass batts have an R-value of about 3.5 (1-inch thickness) but this is not a true R-value since there is no air seal. Blown-in cellulose has an R-value of about 3 to 4 (1-inch thickness) but also no air seal. Our spray-foam has a true R-value of up to 7 per inch, depending on the density foam we use.
3. Fiberglass batts can sag over time, which leaves sections uninsulated and you’ll feel warmer or colder because of it. Spray-foam completely adheres to wood and sheathing; the result is a permanent barrier to heat loss and air entry.
4. Spray-foam will add strength and rigidity to your house. Fiberglass batts will not.