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HomeMy WebLinkAboutThe Huron Expositor, 1988-10-19, Page 9THE HURON EXPOSITOR, OCTOBER 19, 1988 — 9A In recent years, many Canadians have upgraded the energy efficiency of their homes. By adding insulation, installing draftproofing, and improving the efficiency of their heating systems, they have achiev- ed significant savings on their fuel bills. In some cases, energy -conserving im- provements have resulted in unforeseen problems such as moisture build-up on win- dowg or in attics, or inadequate ventilation. Fortunately, there's an easy way to avoid these problems. It's based on what building professionals refer to as the "house as a system" approach, which recognizes that each house is as dynamic and interactive system of heat, air and moisture flows. These flows need to be kept In proper balance, particularly when home im- provements are made. Keeping the flows in balance is a matter of ensuring that changes to the house, like ad- ding attic insulation or draftproofing, do not adversely affect key determinants of the in- door environment such as indoor humidity, ventilation levels and heating efficiency. LOOK BEFORE YOU LEAP Using the "house as a system" approach to home improvements is really a question of looking before you leap. It is a matter of using common sense to anticipate how changes to your house will affect the ex- change of heat, air and moisturewhich is continually occurring between your house and the exterior environment. The'manner in which the exchange occurs depends on three components: the building envelope or shell; the mechanical systems for heating, cooling and ventilation; and your lifestyle. Changes in any one of these components will have impacts on the overall balance of heat, air and moisture flows achieved in the system. This is best illustrated by some examples which cover common changes in the building envelope, mechanical systems and lifestyle. All of the examples outlined below demonstrate how changes in your house in- fluence heat, air and moisture flows, and how care must be taken to properly manage the impacts on all three flows. CHANGES TO THE BUILDING ENVELOPE Your home's building envelope consists of all the exterior surfaces which separate Condensation Condensation on windows is a common oc- currence in many Canadian homes. But it the condensation is persistent and long- lasting, it may be a sign of too much moisture in your home. The source of this moisture should be determined. It may be generated by ac- tivities inside the home, or it may be enter- ing the home from the exterior. Whatever the source, this condition can contribute to serious problems in your home. If you typically have a heavy layer of moisture on the inside surface of double - glazed windows, do a quick survey of the outside structure of your home to ensure that water is not -entering the home through cracks or open joints. You should also check the basement foundation for signs of damp- ness, and the attic area for leaks in the roof. While condensation may be caused by any of the above situations, in modern homes it is more likely a sign of high levels of humidi- ty generated indoors. Mould or mildew in areas where temperatures are low and air circulation is poor (such as closets and cor- ners) is another indicator. Regardless of whether condensation is a result of moisture being generated from in side or outside the home, excessive amounts can cause rotting of wood window frames, sills and trim. In extreme cases, the building's structural materials and insula- tion can be damaged. INTERIOR -GENERATED MOISTURE Condensation occurs naturally when warm, moist air meets a cold surface. Dur- ing winter, the warm air of a heated home holds moisture in the form of water vapour. When the air comes into contact with a cooler surface, like a window or uninsulated wall, it is chilled. As the air cools, the excess moisture condenses out as a liquid or frost, depending on the temperature of the cool surface. The amount of moisture in your home's air (its humidity level) is therefore crucial. Maintaining an appropriate humidity level can often seem like a balancing act: too lit- tle moisture can result in dry, scratchy throats and static electricity, while too much moisture can lead to condensation problems. Logically, the first step in remedying interior -generated condensation problems is to reduce the amount of moisture produc- ed in your home. Normal activities such as bathing, cooking, doing laundry, watering plants and breathing can contribute up to 20 L of water a day to the air in a home. For- tunately, a number of simple measures can be taken to reduce this moisture production: • Lower the humidfier setting on your fur- nace (if comfort will allow, turn it off com- pletely) and limit the use of portable humidifiers and vaporizers. • Ensure your clothes dryer is vented to the outside (never to the attic) and avoid hanging clothes to dry inside during the winter. • Use the vents in your kitchen and bathrooms and make sure they are vented to the outside. Keep your pots and pans tightly lidded when cooking. • Avoid storing or drying large quantities of firewood inside your house. • Ensure that your basement is well drain- ed and damp -proofed. If your home has a crawl space or cellar with an earth floor, cover it with a 0.15 mm sheet of polyethylene to prevent the earth's moisture from entering the air. Open your crawl space vents each spring and close them in the fall. If condensation problems persist after you have reduced moisture'prodprction, you may The house as a system s gip= lir — P G aciu o / C -n "cooc 'C3C'ao�Q 4C' and stored in a ventilated area so that ex- cessive concentrations of fumes will not be a problem after air leakage control, work has been done. In addition, draftproofing work will tend to increase humidity levels in your house since there will be less natural ventilation to expel the moisture produced by indoor sources. To ensure that humidity levels are not too high, watch for symptoms such as substantial condensation on windows during the winter, evidence of mould or mildew on walls or ceiling, or moisture build-up sur- faces in the attic. If these symptoms exist, you will need to implement a moisture control program. This will involve reducing indoor sources of moisture production, through such measures as limiting the excessive moisture produced by washing and cooking, turning off humidifiers, making sure your dryer is vented outdoors, and ensuring that your basement foundation is properly drain- ed and damp -proofed. It also involves ensur- ing adequate ventilation by installing kit- chen or bathroom fans or, if necessary, a heat recovery ventilator. ENERGY-EFFICIENT WINDOWS Replacing older "leaky" windows with more energy-efficient sealed units can sometimes cause problems with excessive window condensation. However, it's usually not the fault of the windows or the installer. It's more likely due to the fact that the win- dows have made your house tighter, causing indoor humidity levels to rise to the point where excessive window condensation oc- curs. The solution is to find ways to reduce indoor moisture production in your house as outlined above. your indoor environment from the outside. These include exterior walls and ceilings, windows and doors, and'the basement. The flow of heat, air and moisture through the building envelope must be properly con- trolled to ensure the optimum in comfort, energy efficiency and structural soundness. Different strategies are required to control each flow: insulation is used to control heat flows; draftproofing and air barriers to con- trol air flows; and vapour barriers to con- trol moisture flows. INSULAIlON Adding insulation to your building envelope will reduce heat losses which oc- cur by conduction, correction and radia- tion. However, it will ate make the outside part of the building envdope colder. This in- creases the potential fa: condensation pro- blems when moisture produced by indoor sources such as cookirg, bathing, clothes washing and respiration moves outward through the building Envelope, either by moisture -laden air flow; or by the process of vapour diffusion. This means that insulation work and structural components oust be protected by an effective air -vapour larrier which is im- pervious to the passage if water vapour and moisture -laden air. A continuous sheet of 6 mm polyethylene provides an excellent air - vapour barrier. Alternatively, the barrier can be achieved by sealing all the air leakage points at cracks and penetrations in the building envelope and applying several coats of an impermeable finish, such as low permeability latek paint, to walls and ceilings. DRAFTPROOFING Installing caulking and weatherstripping to seal the cracks and penetrations in the building envelope will reduce warm air leakage which is a major source of heat loss in most Canadian homes. However, air leakage conte also reduces the natural supply of fr. s air, while it is difficult to seal a house so tightly that fresh air supplies are inadequate, it is still advisable to make sure that your house has sufficient ventilation after air sealing work is completed. Inadequate ventilation may produce air quality problems indicated by stale or stuffy air or lingering odours. If these symptoms occur in your house after draftproofing work has been carried out, it may be ad- visable to increase ventilation by adding kit- chen or bathroom fans. You should also'en- sure that potential sources of air pollution such as paints and solvents are well -sealed a common winter problem want to consider increasing your home's ventilation. Measures cal be as simple as opening a few select winnows a crack and using bathroom and kitcien exhaust fans when bathing or cooking. At the more costly end of the scale, you can hstall a complete mechanical ventilation system, including a heat recovery ventilator tlat warms incom- ing fresh air by extractini heat from outgo- ing stale air. Windows are the most oivious indicator of condensation problems Out they are not necessarily the most serious. Moisture build-up in wall spaces aid attics can com- promise the effectiveness of insulation and may cause rotting of the auilding structure. To ensure that warm moist air is not escaping into wall spaces or the attic, seal ' all areas where air leakage is possible. Ideally, a continuous air -vapour barrier should also be installed and sealed at all edges. Special care shdriild oe given to sealing areas where moisture ii routinely produced, such as the kitchen ani bathrooms. Upper - storey ceilings should also receive close at- tention, In addition toaealing the air leaks, cover these ceilings stith a few coats of oil- based paint, spar varnish or a latex vapour barrier paint to help impede the passage of moisture from the livingspace into the attic. All air sealings should take place from in- side the house and ar-vapour barriers should be installed on the warm side of the insulation. This will alloy moist interior air Fuel Oil Order Now HOME & FARM SERVICE Get dependable heat and free service! When you contract with us, we'll see that you're continually supplied with clean, efficient heating oil for the winter months ahead, Enjoy the comfort and efficiency of fuel oil. that does make its way into the wall spaces or attic to pass through to the outside. EXTERIOR -GENERATED MOISTURE If you have determined that condensation problems in your home are caused by moisture entering from the outside, you should take steps to remedy the situation to prevent structural damage. For example, a leaky roof can contribute significantly to moisture buildup in your at- tic. To combat the problem, seal the leaks and make sure your attic vents are in work- ing order. Install baffles if insulation is blocking soffit vents. The basement can also be a problem area for moisture production, especially if the foundation walls are prone to dampness. You can direct water away from the house by installing eavestroughs and sloping the ground appropriately. If the dampness per- sists, it may be necessary to excavate around the exterior of the foundation walls in order to repair any cracks, and treat the portion of the walls below ground with a waterproofing chemical or asphalt emul- sion. Before backfiling, the drainage tiles should be checked to ensure that they are in good condition. Structural deficiencies may also allow water or moist air to enter your home from the outside. In addition to looking for cracks and open joints in exterior walls and the roof, make sure the flashing is doing its job effectively. Ask about our convenient budget plans available. OIL HEAT IS BEST! Inlk ROWE FUELS Serving Seaforth, Exeter, Goderich, Clinton, Brussels and surrounding areas. Toll Free 1-800-265-5597 Station St., Seaforth 0527-1117 HOW LONG DOES OUR CAR REPAIR GUARANTEE LAST? SEAFORTH SEBRINGVILLE Open Mon thru Fri 8 a m to 12 noon and f p m to 530 p Saturday S a m to 12 30 p to HOW LONG DO YOU PLAN ON OWNING YOUR CAR? 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