R-30 insulation thickness varies based on the type of insulation utilised. The standard thickness of fibreglass panels and rolls with an R-30 insulation value is eight to nine and a half inches.
R-30 high-density insulation can be as thin as eight inches thick, while R-30 standard density fibreglass insulation can be as thick as 12 inches thick.
The R-value of insulation is constantly measured, and the greater the number, the better the thermal resistance. Heat moves more slower through the insulation with greater resistance ratings. R-30 or higher insulation will benefit attics and rooms with high ceilings the most. In most cases, attic cavities are large enough to handle R-30 insulation, which comes in a variety of thicknesses depending on the supplier and insulation type.
When estimating the value of existing insulation in your home, a decent rule of thumb is to measure the thickness. If the width is less than 11 inches, more insulation may be required to raise the resistance rating to R-30 or higher.
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