Installation Guide

Insulating Around Ductwork:

Insulating Non-standard Size Spaces and Narrow Cavities:

Insulating Around Recessed Lights in Ceilings:

Insulating Scuttles & Pull-Down Stairways:

Knee Walls:

To insulate around heat ducts in ceilings or ﬂoors, cover ducts with insulation so the air temperature in the ducts can be

maintained more efﬁciently.

In basement ceilings, whenever possible, pull the insulation behind any ductwork.

You will need to trim and piece the insulation.

Recessed lighting ﬁxtures, as well as fan motors and other heat sources protruding into the ceiling, are

a potential ﬁre hazard. Building and ﬁre codes require that there be at least a 3" clearance from any

heat-generating source—including chimneys—unless the ﬁxture is IC rated. This rating will be clearly

marked on the ﬁxture.

To ensure that this 3" clearance is maintained, you can install a bafﬂe made with metal, cardboard or

sheet metal around the heat source. If there are facing materials, trim them around the bafﬂe to ensure

adequate clearance from the ﬁxture.

A scuttle is the opening for accessing the attic. Scuttles, pull-down stairways and other attic access holes should also be

insulated to the same R-value as your attic.

Many attics are ﬁlled with loose-ﬁll insulation. However, that does not work for scuttles or pull-down stairways. Batt

insulation, however, can be glued directly to a scuttle hatch. Pull-down stairways may require a build-up framework to lay

batts on and around.

If you have pull-down attic stairs or an attic door, seal these similarly: Weatherstrip the edges and put a piece of rigid foam board

insulation on the back of the door.

Insulation installed in knee walls should be secured to prevent it from falling out of the cavity and

covered with an air barrier material. The air barrier should be a durable material which is permanently

attached to the wall framing.

SPECIAL CONSIDERATIONS,

CRITICAL DETAILS, & TIPS:

1. Cut the insulation and facing about an inch wider than the space using a sharp utility knife against a

safe backstop, such as an unﬁnished ﬂoor or other smooth, ﬂat surface. Always cut on the unfaced

side of the batt.

2. For shorter spaces, cut the insulation to ﬁt properly. Don’t double it over or compress it. Compression

changes the R-value of the insulation.

3. If it takes more than one batt to ﬁll the height of a wall cavity, you need to make sure the two pieces

are butted snugly together.

The area during and after installation of ﬁber glass batts may be used by other trades or occupants. There are no time

restrictions for re-entry into the area.

RE-ENTRY/RE-OCCUPANCY TIMES:

ASTM C1320 Standard Practice for Installing mineral Fiber Batt and Blanket Thermal Insulation for Light Frame Construction