Chapter 6 Index

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• Insulation and Weatherproofing
  
• Attic Ventilation
  
• Wall Insulation

Energy conservation

With the high cost of utility bills these days, energy efficiency is as important to homeowners as any maintenance issue. We are inundated with promotional literature and advertisements to insulate our homes or to install new siding, double-glazed replacement windows, and various specialty products. Unfortunately, no one has any incentive to advertise inexpensive, commonly available materials, or techniques. A little common sense goes a long way in evaluating these products and tailoring the best solutions to each situation.

Insulation and weatherproofing

Begin in the attic. Heat rises-so it is extremely important to prevent heat from escaping from the living spaces through the ceiling. Unfinished attics are easy to insulate with fiberglass batts, or loose material; RG&E recommends a minimum level of R-30 or about 10 inches of fill.

Heated attics and cathedral ceilings introduce a difficult problem. To help prevent ice dams, any insulation installed in the rafter cavity must include an open space for ventilation in conjunction with soffit vents and ridge or gable vents. This allows cooler air in through the soffit vents; as it rises, it cools the roof surface and then leaves through the ridge or gable vent as warmer air. For more insulation advice, refer to the attic ventilation section in this chapter.

One area that is easy to insulate but often overlooked is the rim joist just above the foundation and below the first-level floor.

Weather-tight windows and properly weatherstripped doors are very important. Weatherstripping comes in a variety of styles. Don't use cheap adhesive-backed foam or plastic. Use spring metal or one of the new tubular gaskets that is tacked onto the stop or installed into a special groove in the stop. Refer to chapter V for more information on window weatherstripping and sources for materials.

Check areas of suspected air infiltration around doors, windows, and electrical outlets with a lighted candle or cigarette. If the candle flickers or the smoke is disturbed, you've discovered an area that needs attention. Install special insulators under perimeter wall electrical receptacles and switches. Long cloth bags filled with sand are good for the bottom of doors and the meeting rails of windows. Finally, don't forget simple passive techniques. Let the warm sun flood your rooms in the daylight and pull the curtains or shades in the evening to keep the warmth in the house.

On the exterior, seal vertical cracks around window and door casings and corner boards with a paintable acrylic latex caulk. Pay special attention to holes around pipes, electrical outlets, and HVAC equipment. Don't caulk the horizontal cracks under clapboards-these cracks provide a good escape route for vapor passing through the walls. Repoint or repair cracks or holes in the foundation or any masonry surfaces.

INSULATION PRIORITIES

Attic ventilation

In cold and warm weather, attic ventilation goes hand-in-hand with energy conservation. In our snowy climate it is important to maintain cold attic temperatures, especially when snow is piled on the roof. If your attic is warm, accumulated snow will melt rapidly and refreeze as it drips over the eaves or into the gutter, creating a bulge or dam of ice. As this ice dam grows, melting snow above it cannot run off the eaves. This moisture backs up under the roofing.

Typical signs of ice dams are bulging gutters, long icicles, peeling paint, and damaged boards under overhangs. Tea-colored icicles usually indicate that moisture has penetrated under the roofing, soaked old wooden shingles or decking, and then escaped with an additional load of dirt, soot, and tannin. On houses with shallow overhangs, this moisture can enter the wall cavity or come inside to damage walls, ceilings, decoration, and woodwork. Although various methods of flashing, ice shields, and tar-reinforced layers of felt are used to deter this damage, it is best to maintain a cool attic and prevent the problem completely.

Houses with converted attics are subject to ice dam problems. Construct attics in a way that ensures proper ventilation. If the space is large enough, a room can be enclosed with adequate ventilation behind knee walls and over the ceiling. If your attic enclosure uses the rafters as framing for the ceiling (often called a cathedral ceiling), install overhead insulation with at least two inches of space between the roof deck and the insulation to promote the free flow of air from soffits to the ridge. One way to do this is to use prefabricated rafter vents, available at most home centers and building supply stores.

If you are experiencing ice dam problems and your enclosed attic does not have plumbing, it may help to turn off the heat to this area when snow is piled on the roof. In the long run, however, remedying your attic ventilation problem will be much more economical than repairing damaged soffit boards, gutters, and paint. Also, remember that covering your soffits and facia with aluminum or vinyl covers the problem; it does not solve it.

Since attic temperatures rise significantly in the summer, adequate cross-ventilation can also make a big difference in the comfort of your home in warm weather. Excessive heat and condensation created by inadequate ventilation shortens the life of your roof and makes upstairs living spaces unbearably hot. If your house is air-conditioned, adequate attic ventilation can lengthen the life of your cooling equipment by lowering the ambient temperature, thus creating less demand for its use.

Typical ventilation requirements are usually minimum standards governed by factors such as color of the roof (black roofs are hotter than white), the amount of insulation in the attic floor, the presence or absence of a vapor barrier, the presence of screens over openings, and the amount of shade protecting the roof. One square foot of cross-ventilation for every 300 feet of attic space is a rule of thumb; however, an attic with too much ventilation is rare.

Static ventilators such as fixed gable louvers work best when upper and lower ventilation is provided. For instance, soffit vents in combination with gable or roof ridge vents enable cooler air to enter at soffit level and escape as hotter air through the gable or ridge opening. In many post 1930 homes, the absence of cornice overhangs makes this option impossible. One alternative is the installation of small pan vents in combination with ridge or gable vents. Attic fans can also be used to ventilate the attic and cool your house. Installed in the gable or in the upstairs ceiling, an attic fan works by replacing hot indoor air with cooler air pulled in through open windows and doors. Install venting equipment sensitively so that it does not aesthetically detract from your home. If possible, venting equipment should not show from principal elevations.

SOFFIT & RIDGE VENTS

INSULATING THE RIM JOIST

ATTIC VENTILATION

Wall insulation

VAPOR BARRIER

Since the energy crisis of the 1970s, there has been a lot of confusion about blown-in wall insulation. The problem with adding wall insulation to an old house is that there is seldom an opportunity to install a vapor barrier. A vapor barrier is an impermeable material (such as heavy plastic) installed on the warm side of the framing under the plaster or wall board. Old houses were nearly always a little drafty, and any condensation that developed in the walls between the warm interior and cold exterior condensed and dissipated. When insulation is added to the wall cavity without a vapor barrier, condensation can build up in the loose insulation with no opportunity to escape. This constant dampness can rot sills, attract insects, and create a terrible paint problem; thus, the need for a vapor barrier in our cold climate.

Since most heat loss is through drafty windows, doors, uninsulated attics, and uncaulked cracks, blown-in insulation may not be cost-effective if your house is appropriately weatherproofed. Combine the threats of potential rot, paint failure, and the unsightly holes drilled all over your house, and retrofitted insulation may not seem like an indispensable part of your energy-savings plan.

If your walls have been insulated and you are worried about potential problems, the following recommendations should help: (1) Vent your bathroom and kitchen range to the outside. (2) Use humidifiers judiciously or not at all. (3) Cut down the number of house plants. (4) Don't take long showers. (5) Make sure your basement is dry and that there is no standing water. (6) Provide adequate attic ventilation. (7) Make sure the heating equipment and the hot water heater are vented properly.

Since most vapor escapes through cracks, baseboards, window and door trim, and electrical outlets, seal these areas as well as possible. Consider using a vapor barrier paint on interior perimeter walls. Barrier paints aren't the perfect answer to this problem, but they do offer some resistance to the vapor. Some companies manufacture specific vapor barrier paints, but most oil-base enamels are adequate.

If you've weighed the pros and cons and decided to insulate your walls, ask for fiberglass fill; it settles less than cellulose fill. Don't allow the contractor to drill holes in your siding. Insist that clapboards be carefully removed and replaced, or have holes drilled in interior plaster walls. A thermographic scan conducted during cold weather will indicate if your blown-in insulation effectively fills every wall cavity. For more information about this service, contact Ergonomy Inc. at 425-3910.

RG&E offers several incentives to help make your home more energy efficient. If you want a second opinion about a furnace replacement, a free energy audit, or their booklet "How to Save Energy and Money in your Home," call them at 546-2700.

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