Home Improvement : Move Up in the World by Remodeling the Attic : When additional living space is created upstairs, insulation is the main concern.

People who need more living space in their homes but don’t want to expand the outside dimensions of the house are inclined to look up--toward the attic. The most important factor to consider in the finishing of the attic is the amount and placement of the insulation.

Most unfinished attics have some insulation in the attic floor. That insulation was originally thought to be needed to prevent the movement of rising heat through the ceiling of the living area and attic floor into the attic itself. Otherwise energy and money would be wasted in heating an attic in which no one ever spent time.

It now has been determined not only that the amount of insulation in the attic floor is insufficient to take care of the requirements of an area where people live but also that the large savings made possible by proper insulation applies just as much to a house with air conditioning as it does to a house with heat.

Check the insulation

A check of the insulation in the attic floor usually will reveal about 3 inches of insulation. The National Bureau of Standards and other agencies concerned with energy have estimated that 6 inches of insulation would fill the bill in the attic floor in regions of relatively mild winters. Amounts greater than that are justifiable where the climate is colder or warmer than average. Other reasons for increasing the insulation would be where energy costs are expected to rise and where walls are poorly insulated.

When adding insulation to the floor, use batts or blankets without vapor barriers. If the new installation has such barriers, remove or slash them with a knife. When it is inconvenient to use batts or blankets, loose insulation can be used. If, by some chance, the attic floor had no insulation and you are utilizing batts or blankets with vapor barriers, make sure those barriers are facing downward.

Insulation to be placed in the walls of the new living quarters should be set into place after the framework is up but before the full walls are up. Staples used on the flanges of the insulation should be spaced about 8 inches apart. You may want to look into what are called wire insulation supports.

Because the object of a vapor barrier is to keep moisture out of the insulation itself, a cut or tear in the barrier must be repaired instantly. This can be done with a piece of barrier from a scrap section of the insulation or, in the absence of that, a piece of polyethylene. Any opening in the barrier will permit moisture to get through and thus destroy the entire purpose of the covering.

Prevent leakage

No matter how efficiently your attic is insulated, there will be a considerable amount of leakage. Air, besides escaping around window frames, can get through electrical connections, plumbing stacks, ducts and whatever connections have been made to make living upstairs comfortable. A rule of thumb: Wherever you see any gap that might permit air or heat to escape, plug it up somehow, with weatherstripping, caulking compound or anything at all that will do the job. One way to handle this, especially around window frames, is with the wool from an insulation blanket. Pull it from a blanket and stuff it by hand into the opening. Since insulation fiber can cause skin irritation, wear work gloves. It’s also a good idea to wear clothing that covers all the skin.

Most important, there must be plenty of ventilation at the top part of the attic. There usually are a couple of vents at the gable ends, but a combination of vents there and at the eaves is much better. Moisture vapor must be permitted to get out of the attic, either through the vents or with assistance from one or more fans.

Detailed instructions on insulating an attic are included in Andy Lang’s booklet “Save Money by Insulating.” Send $1 and a stamped, long envelope to Know-How, P.O. Box 477, Huntington, NY 11743.