Insulation 99 Violations 101 Leakage 101 Fire hazards 102 Ventilation 103 Attic fans 105 Structural 105 Checkpoint summary 105
Once you are inside the house, if there is an accessible attic, it should be the first area inspected. There are basically two types of attic: full and crawl.
A full attic is one in which a person can easily walk around. Usually there is a floor in this type of attic, although the walls and ceilings are unfinished. There might be partition walls forming finished rooms with sloping or horizontal ceilings. Access to a full attic is usually through a finished staircase.
In a crawl attic, which is completely unfinished, the roof is sufficiently close to the floor so that to get around it is necessary to crawl or stoop over. The crawl attic usually does not have a floor. The ceiling joists from the level below are exposed. When getting around in this type of attic, be careful to walk only on the exposed joists. If you accidentally step between the joists, you will probably frighten the pants off of anyone in the room below because your foot will go right through the ceiling. Access to a crawl attic is usually through a ceiling hatch located in a closet or hallway or through hidden folding or sliding steps.
Inspecting an attic can reveal problems of which most homeowners are not aware, some of which might be potentially dangerous or costly to repair. It is not uncommon for a homeowner to say that he has lived in his house for over twenty years and has never gone into the attic. Incidentally, if the homeowner does say this, you can be sure that at the very least, the attic is inadequately insulated by current energy standards.
Insulation and roof leakage are probably the only items most people consider when thinking about the attic. However, there are other items of importance and concern, such as ventilation and its associated problems, fire hazards, electrical and plumbing violations, improperly discharging vents, and open duct joints.
The attic area should be adequately insulated to minimize heat loss. The insulation needed in the attic will of course depend on the geographic location of the structure. (See chapter 18 to determine the proper insulation for your area and for a general description of the various types of insulation.) In both crawl and unfinished full attics, the insulation should be located in the floor (between the floor joists) and not between the roof rafters. (See FIG. 9-1.) Otherwise, heat from the rooms below will escape into the attic.
The insulation should be installed with a vapor barrier facing the heated portion of the structure and not the unfinished attic area. A vapor barrier is aluminum foil, a plastic sheet, or an asphalt-impregnated paper that prevents moisture movement from the heated portion of the house into the unfinished attic area. If the vapor barrier is incorrectly positioned (facing up into the unheated, unfinished attic), condensation problems can develop during cool weather. Moisture rising from the heated areas below condenses upon contacting the cool vapor barrier. Depending on the amount of vapor, the resulting condensation buildup can reduce the effectiveness of the insulation and cause peeling and flaking of the painted ceilings and walls in the rooms below.
If there are heating or air-conditioning ducts in the attic, check to see whether they are insulated. Metal ducts often have insulation in the inside, so tap the duct with your flashlight. If you hear a hollow sound, there is no insulation. If there is a dull thud, insulation is present. The more insulation on a duct, the less the heat loss during the winter and, in air-conditioning ducts, the less the heat gain during the summer. Generally, a minimum of 3 inches of insulation wrapped around the outside of the duct will substitute for missing insulation. If the duct is used for air-conditioning, the insulation should be covered with a vapor barrier to prevent condensation from forming.
In the northern sections of the country, when there is a furnace in the attic, insulation between the roof rafters as well as in the attic floor is recommended. To ensure proper ventilation and avoid condensation problems between the rafters, it is important to leave a ventilated air space between the top of the insulation and the underside of the roof deck. The insulation and the associated air space will help keep the roof deck cool. If the insulation is not between the rafters, heat from the furnace will warm the roof deck and melt the bottom layer of snow that has accumulated on the roof. This often results in an ice dam (see chapter 2).
Often, a homeowner adds additional insulation to the attic to bring the total insulation up to current energy standards. The insulation added should not have a vapor barrier if the existing insulation has one. All too often the homeowner adds insulation with a vapor barrier, which can then cause condensation problems. Look at the insulation in the floor. If there are two layers of insulation and both have vapor barriers, the upper barrier should be slit with a razor blade to allow moisture movement.
If there is a full attic with partition walls forming rooms, the insulation should be located on the unfinished sides of the partition walls and on the ceilings of the rooms. Occasionally, insulation is placed between the roof rafters and not between the floor joists and the partition walls. This installation is inefficient because the heat will escape into the unfinished areas.