A Lesson on Insulation

Earlier we covered the topic of ice dams.  The culprit of many ice dams can be poor insulation in the attic.  Now that the warm weather is on its way it may seem this problem can wait another season but poor insulation can also mean a hotter house on warm days.  The question now arises: how do I best insulate my attic?  There are many different ways this can be done.  Below is a list of popular insulation materials.  Usually a combination of insulation types is used in a home.

Type Material Appearance Pros Cons
Fiberglass   Glass Fibrous wool / cotton candy.  Can be pink, yellow, or white, depending on manufacturer. Easy to install, inexpensive Dangerous to breathe (wear a mask when installing), heat and moisture compromise quality, mice will nest in it.
Rockwool (new version)  Minerals Grey wool blanket Easy to install, more airtight, safe to install by heat sources, can get wet, nontoxic environmentally friendly material More expensive than fiberglass insulation (10% or more)
Foam Board    Polyurethane Foam boards that can be blue, grey, or pink depending on manufacturer. Easy to install where appropriate. Rigid insulation is not appropriate for every part of the home.
Blown Insulation    Made out of various materials including cellulous, fiberglass, and minerals White fluff Spreads evenly, fills in between outlets, wires, pipes and ductwork, and eliminates gaps in insulation.  Good for attic floor. Need professional with equipment to install.
BIB (Blown in Blanket)  Fiberglass, fabric White fluff held in place by fabric sheets. Fills space between studs very well. Need professional with special equipment to install.
Spray Foam (Open Cell)   Chemical combination. Made up of broken, unclosed bubbles.  Soft consistency Shaving cream Inexpensive, fills space well, water can pass through (can be con if you want it to block water) Need professional to install, R-Value is very good, but closed cell is better (see below)
Spray Foam(Closed Cell) Chemical combinationMade up of dense, closed bubbles.  Denser, harder consistency. Shaving cream High R value, water and air cannot pass through Need professional to install, more expensive than open cell
Fiberglass Insulation

Fiberglass Insulation

When looking at insulation you are going to see a lot of talk about “R-Value”.  According to EnergyStar.gov, R-Value is “a measure of insulation’s ability to resist heat traveling through it.”  The higher the R-Value the more effective the insulation.  A chart on the same website shows homes in Maine to require insulation with an R-Value of 49-60 for the attic walls and 30-60 for the floor, depending on the current amount of insulation in the attic.




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