When It Comes to Insulation, Fluff Your Fiberglass

It is easy to insulate walls, ceilings and floors when you know a few simple tricks.

Although there are several choices, fiberglass insulation is the best. It is lightweight, inexpensive, relatively easy to install and holds up as well as, if not better than, all the other types. The paper-faced type acts as a vapor barrier, yet still breathes. This is important because you don’t want to build a barrier that can become a condensation chamber--something that can happen with foil-faced insulation.

Get the kind of insulation that comes in 16- and 24-inch-wide rolls and precut lengths called batt insulation. Batts are easier to handle than the type that consists of thousands of tiny chunks known as loose-fill insulation. Also, batts stay in place better than loose-fill. After years in a wall cavity, loose-fill insulation can settle and become compacted. Insulation stops working in this condition because the air spaces between the fibers are the actual insulators.

In an attic there is a tremendous amount of pressure developed as air enters through the eave vents and travels upward to exit through the upper portion of the roof. All of this air movement can push loose-fill insulation into piles, leaving some areas unprotected.

Here’s a technique to remember: Fluff your insulation as you install it. Before putting each piece in place, simply shake it out gently. The tendency is to forcibly stuff insulation in place--the “more is better” theory. With insulation you want a lot, but you want it to be as fluffy as possible.

Another tidbit: If you want to figure how much insulation you will need, multiply the length times the width of the area to be insulated and divide the result by the number of square feet shown on the package of insulation. Let’s say the ceiling is 12 feet long and 12 feet wide. Twelve times 12 equals 144 square feet. If the insulation you choose comes in a 100-square-foot package, you will have to purchase two packages.

If the insulation is faced, be sure that the face of the insulation is placed on the house side:

* For ceilings the face goes down.

* For floors the face goes up.

* For walls the face goes on the inside.

These rules of thumb apply in every case. Also, if you are adding insulation, don’t worry about what kind exists or what condition it is in. Your new insulation can be applied over any other type or brand. All types of insulation are compatible. Some might last longer, work better or install easier than others. Color doesn’t make a difference either.

In an attic you must be especially careful about insulating around recessed light fixtures. A recessed light fixture can easily overheat if covered with insulation. This is a big issue that is scrutinized closely by building officials during insulation inspection. Most insist on some kind of baffle between a recessed light fixture and the end of the insulation.

There are two kinds of recessed light fixtures--regular and IC. IC fixtures have a housing built around them that prevents insulation from coming into contact with the hot part of the light can--a five-sided space. If you don’t have IC fixtures, make sure to keep the insulation at least 6 inches away from recessed light fixtures. That’s another reason why we don’t care for loose-fill insulation. Air currents in the attic can easily cover recessed cans and create a major fire hazard.

Note: If you have recessed light fixtures that shut off after being on for a while, then turn back on again after a while, chances are they are overheating. On modern recess light fixtures there is an onboard fuse called a thermocouple that shuts the fixture off when it overheats.

When the fixture cools, the fuse resets and the light will come on again by itself. This could indicate the insulation condition we have just described, and warrants a jaunt into the attic.

*

Readers can mail questions to On the House, APNewsFeatures, 50 Rockefeller Plaza, New York, NY 10020, or e-mail careybro@onthehouse.com.