Fiberglass, mineral wool and natural wool fibers are used to construct insulating materials called rolls and batts. While each is similar in function, the design of each product affects homeowner choice.
Both batts and rolls are pre-cut to fit snugly between wall studs, ceiling and floor joist. However, only rolls or blanket insulation provide continuous coverage because of their extended lengths.
Both materials come with or without backing. Some manufacturers carry products with paper or plastic backing, which acts as a vapor barrier to prevent moisture from condensing.
You may find it easier to install batt insulation in attics, crawlspaces and ceilings because rolls could be awkward to work with in odd-shaped areas. Certain batts have flame-retardant backing for use in basements where the insulation may be left exposed. Roll insulation may have paper backing with edges used to secure the roll into place between wall studs.
R-value helps determine the insulation's ability to retain heat. Both batts and rolls have a rating of 3.2, although high performance fiberglass batts and rolls offer a 3.8 rating.
Prices for batt and roll insulation are about the same.