Insulation Terms

acoustical insulation: insulation designed to reduce the transmission of sound through walls and floors/ceilings; most fiber glass insulation provides sound and thermal control.

ballast: something that gives stability.

baffle: device to maintain a ventilation space between the insulation and roof deck, assuring air flow from the eave/soffit vents to ridge vent or other roof vents in attics and cathedral ceilings.

band joist: vertical member that forms the perimeter of a floor system in which the floor joists tie in. Also known as the rim joist.

batt: precut length of insulation to fit typical wall cavity heights and widths. Batts are designed to use in wall cavities, attics, floors, standard wood framing, and standard wood joists-vaulted ceiling cavities (cathedral ceilings). They save you time in installation and can be friction-fit installed between studs.

blanket insulation: large panels of insulation made especially for insulating concrete walls in basements and crawl spaces. Can also be used in large open areas such as floored attics.

blow-in insulation: insulation that is blown into position through a hose connected to a blowing machine.

cavity: the empty area between studs or joists where insulation is placed.

collar beam: horizontal board joining two opposite rafters above the wall plate. Also called a collar tie.

condensation: when a vapor becomes liquid as it cools. Appears on surfaces as a film or water drops.

duct (ductwork): the channels through which hot and cold air is blown in a building’s heating and cooling system.

eave vent: vent openings located in the soffit under the eaves of a house to allow the passage of air through the attic and out the roof vents.

face staple: stapling facing flange to a stud or rafter.

flanges: tabs that stick out beyond the edges of faced fiber glass; staple these to the studs or framing to secure fiber glass in the cavity.

fiber glass: long, resilient bonded glass fibers. Garrity fiber glass insulation is made with an acrylic thermosetting binder instead of formaldehyde.

formaldehyde: a colorless, pungent irritating gas (CH20) used chiefly in aqueous solution as disinfectant and preservative and in chemical synthesis. Most insulation contains formaldehyde in its binder. Garrity Insulation has completely removed formaldehyde—a known human carcinogen—from its products.

furring strips: flat pieces of wood used to build out framing to an even surface.

header joist: the large beam or timber into which the common joists are fitted when framing around openings for stairs, chimneys or any opening in a floor or roof.

Hilti-type gun: a tool used for driving fasteners into concrete.

IC rated: describes an electrical fixture that does not require a clearance between the fixture and insulation material.

inset staple: stapling to the interior edge of a stud or rafter as opposed to the face or leading edge.

insulation density: the denser the insulation, the more fibers per square inch and the higher the R-value.

insulation supports: 16” or 24” wire rods (sometimes called “Tiger Teeth” or “lightning rods”), chicken wire or crisscrossed wire used to hold floor insulation in place.

joist: any of the parallel beams of wood, metal or concrete that support a floor, roof, or ceiling.

knee walls: walls that support roof rafters with a wide span or finish off an attic. Also side walls that back up to an unconditioned space such as an attic or garage.

R-value: ability of a material to resist heat flow; the higher the R-value, the more powerful the insulation.

ridge vent: a vent on the ridge line of a roof. Allows ventilation in attics or cathedral ceilings.

roll: longer strip of insulation designed to fit standard-width wall cavities. Rolls are ideal for long, unobstructed spaces such as attics or crawl spaces and you can cut them to fit any size wall in any part of the house.

scuttle: a covered opening for accessing an attic.

sill plate: the framing member anchored to the foundation wall upon which studs and other framing members will be attached.

soffit: the underside of a part or member of a building extending out from the plane of the building walls.

stringer joist: the large beam or timber running parallel to the common joists when framing around openings for stairs, chimneys or any opening in a floor or roof.

stud: one of the small uprights in the framing of the walls of a building; insulation is placed between and sometimes attached to studs.

thermal insulation: insulation designed to resist the transfer of heat; most JM fiber glass insulation provides thermal and sound control.

top plate: the horizontal member nailed to the top of the studding of a wall.

truss: a structural framework based on a triangular system, used to span, reinforce, or support walls, ceilings, or beams.

unfaced insulation: insulation without facing; does not contain a vapor retarder.

unvented crawl space: a crawl space that opens to the outside.

vapor retarder: treated paper or plastic that is either attached to insulation or plastic that is placed over unfaced, installed insulation to keep the moisture in the air from condensing in the insulated cavity.

vent chute: a prefabricated, formed sheet used to allow air to flow between a soffit and a ceiling.

vented crawl space: an enclosed crawl space that is part of a basement and does not open to the outside.