What it is:
Blow-In Insulation, also referred to as cellulose insulation is a soft fiber material, often made of recycled paper products that is blown into a space, often with the use of equipment (can easily be rented). It is most often used in flat spaces like an attic rather than walls because of settling issues but it can be blown into vertical spaces as well. The purpose of insulation is to keep hot and cool areas separate. It is equally important in hot climates as it is in cold climates. It is also a sound barrier keeping your home quiet and private. Most insulation types do this by trapping air, blow-in insulation accomplishes this by having a thin fiber like materials create air gaps. Like other types of insulation it does not work as well when compressed.
Blow-in insulation can be used between studs, in roof spaces and in floor boards. For walls it is easiest for the DIYer to blow in the insulation after the sheathign and interior wall finish is up. Generally a small hole is cut in the interior side of each stud bay, insulation is blown in and then the material is patched. This can be labor intensive but is a great way to insulate existing structures which may not be insulated already. There are other options best left to professionals that use blow in with binding materials to allow the insulation to stick vertically not requiring the interior finish to already be installed. When installing blow-in insulation you should wear gloves, safety glasses and a breathing mask so that fibrous pieces are not ingested or irritating to your skin.
Blow-in insulation is affordable compared to other insulation types. It is light weight generally 75%+ recycled materials and widely available at home improvement stores. There is very little toxic/harmful materials resulting in less off-gassing and a cleaner home air environment. The fibers are generally treated with a borate based or saline solution to reduce fire hazards, mold and pests. There is less embodied energy used to produce blow-in insulation than nearly any other type.
You can get a fairly limited R-Value for thickness (space required) compared to other insulation types, a 3.5″ wall (standard 2×4) will get about an R-13. Blow in insulation settles over time often leaving air gaps that are insulated at the top of a wall as well as compressing the insulation at the bottom, diminishing effectiveness of the insulation. Water damage will completely undermine any insulation value of most blow in insulation. Even though it is great for fitting into tight spaces, say around plumbing pipes, it is not suggested to use blow-in insulation in floor systems and plumbing walls for this reason, if there were to be a flood/leak you would need to redo the entire floor insulation.
Tiny House Specific and Regional Considerations:
Often times when dealing with tiny houses space is a premium and most want more interior space, in order to get energy codes suggested R-Value with blow-in insulation alone you would need to increase your walls to 2×6 construction. You are of course not required to follow energy codes for tiny homes but ‘code’ is typically the minimum level suggested for energy savings and comfort. This all varies quite a bit by location but if you experience either high temperatures or very low temperatures you will notice a big impact from quality insulation and R-values. Tiny houses are exposed to more vibration than a standard house, this will cause settling to occur much faster than in a standard house.
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