Blown In Attic Insulation Or Loose-Fill Insulation - Which Is Better?
Cellulose, cotton, wool, wood shavings, recycled glass and spray foam are used as blown in attic insulation for roofs and lofts. This type of insulation material is useful to fill gaps in walls or wall cavities, attics and other hard to see and reach areas, which need insulation. It's extremely convenient for this type of insulation as the loose-fill or spray foam can reach every recess, cavity and crevice, fitting in and adapting to the shape of the space that needs to be filled in.
For materials like cellulose the loose fill is usually blow in with some moisture so it can go and stick to the walls. After all the insulating material is sprayed to fill the space it has to be allowed to dry completely. Wet cellulose or similar insulating materials are bad insulators and there is rapid loss of r-value. So, give enough time for it to dry before sealing it off.
What is the procedure for Blown In Attic Insulation?
It's fairly simple. Two holes are drilled in the wall - one at the top and other at the bottom. if it's in attic or basement cavity - then two holes for each cavity or section needs to be drilled. Blow in the loose-fill from bottom. Then top-it up by blowing in more material through the top hole. Wait till the insulating material is completely dry. Use hot air if necessary. Then seal off the holes.
Advantages of loose fill insulation
Blown in attic insulation has certain advantages that are environmentally friendly - most of these are recycled materials like newspaper, recycled cloths, wool and safe for people working with these insulating materials. With an r-value 3.4 - 3.8 per inch. With batts it's difficult to seal of odd-shaped spaces. Loose fill has no such problems. No petrochemicals or chemicals so, no danger of any toxins getting into the air.
Disadvantages of loose fill insulation
There are certain shortcomings of blown in attic insulation that we need to consider. It does not seal of bypasses as well as spray foam insulation. If the insulating material is very heavy the ceiling might sag. The contractors will know how to avoid this problem. Cellulose settles over time. This reduces its r-value significantly.
It can absorb moisture so suitable provision needs to be made prevent this. If air infiltrates fiberglass loose fill then it can severely affect the r-value of this loose fill. Fiberglass loose fill does not absorb water but if it gets wet then its insulating properties gets affected.
Compared With Spray Foam Insulation
Spray foam poly urethane insulation has a higher r-value compared to cellulose of fiberglass loose fill. The foam once sprayed expands and seals of all the nooks and crannies in the spaces much more effectively than blow in cellulose or fiberglass. The adverse impact of hydrochloroflurocarbons on environment and ozone layers is well known.
Also, if this insulation material catches fire, it releases toxic fumes, which are bad for health. All foam insulation need fire retardants and drywall backing.
Building codes for insulation change from place to place. So, some place like Houston will have different requirement than say New York. Find out if you can opt for green and safe blown in attic insulation for your home.