Managing Your Homes Moisture. Moisture management can be accomplished by controlling the three ways that moisture enter your home, which are: air currents; by diffusion and heat transfer. Air movements accounts for around ninety eight percent of all moisture in your home. Moisture transfer by air currents is very fast-in the range of several hundred cubic feet of air per minute. Sealing air pathways is one of the most important methods of reducing moisture in the home. Seeping through basement walls, showers and even cooking are some of the most common ways moisture can enter your home.
If you have an older home or cottage with a crawl space then seperating your crawl spaces dirt floor from your living area will drastically reduce moisture rising up and into your home. New construction is required to have this by current Building Code requirements. Ventilation of crawl space is very important during summer months.
Carpet on concrete floors can absorb moisture and serve as a place for pollutants and mould to grow. Use area rugs which can then be taken up and washed often. In climates with high humidity, if carpet is to be installed over a concrete floor, it may be necessary to use a vapor barrier (plastic sheeting) over the concrete and cover that with sub-flooring (insulation covered with plywood) to prevent a moisture problem.
Mould is everywhere and can grow on your walls, floors, appliances, carpet, or furniture. Any of these items can provide the food mold needs to grow. But the thing all molds need most is moisture, so you’re most likely to see mold in damp places such as bathrooms, kitchens, laundry rooms, basements, and crawl spaces. Use dehumidifiers and air conditioners, especially in hot, humid climates, to reduce moisture in the air. Keep indoor humidity below 60% if possible. You can measure relative humidity with a hygrometer, an inexpensive instrument available at most hardware stores.
Some simple methods of protecting your home are: Keep air conditioning drip pans clean and if using a window unit ensure moisture is draining properly. Keep the house warm in cool weather, as the temperature goes down, the air is less able to hold moisture and it condenses on cold surfaces, which can encourage mold growth. Add insulation to cold surfaces, such as exterior walls, floors, and windows to reduce condensation. Dry wet areas within 24 to 48 hours to prevent mold growth. Fix leaks and seepage. The ground should slope away from your house. If water is entering the house from the outside, your options range from simple landscaping to extensive excavation and waterproofing.
Relative Humidity is the measurement of moisture in the air. For example, according to the psychrometric chart, air at 68 F (20 C) with 0.216 ounces of water (H2O) per pound of air (14.8g H2O/kg air) has 100% RH. The same air at 59 F (15 C) reaches 100% RH with only 0.156 ounces of water per pound of air (10.7g H2O/kg air). The colder air holds about 28% less moisture than the warmer air does. The moisture that the air can no longer hold condenses on the first cold surface it encounters — the dew point. If this surface is within an exterior wall cavity, the result will be wet insulation and framing.
Many people complain about moisture on their windows in the winter. Excess moisture condenses on window glass because the glass is cold. Other sources of excess moisture besides overuse of a humidifier may be long showers, running water for other uses, boiling or steaming in cooking, plants, and drying clothes indoors. If you are using a humidifier then it is set too high and should be turned down.
Ventilating roofs in hot and humid conditions may add (rather than remove) moisture from attics and enclosed roof spaces. However, not ventilating roofs may void the asphalt-composition roofing manufacturer’s warranty, and slightly decrease the life expectancy of the roofing material due to increased temperature of the roof’s surface.
Roof overhangs and projections, such as porch roofs and overhanging upper floors, provide a primary means to deflect rainwater away from building walls. Thus, the potential for water penetration through siding, windows and doors is minimized. Because the protection of roof overhangs increases with increasing overhang width, larger overhangs than those recommended in this section may be important in the consideration of weather-resistant wall-barrier design.
The installation of even the most weather-resistant wall envelope system on a house does not diminish the need for proper installation, particularly with regard to flashing details at penetrations. In addition, the use of roof overhangs provides performance benefits for all cladding systems by reducing the moisture load experienced over time, and by allowing greater opportunities for walls to dry in the event of periodic wetting due to wind-driven rain. The life expectancy of various siding materials may vary widely, from 10 to as much as 100 years or more, depending on type of material, climate exposure, maintenance, and other factors.
Relying on window and door products that are labeled according to standard test methods does not necessarily guarantee that water leakage will not occur through frames into walls. Frames that rely on seals and sealants at internal and exposed joints will eventually leak water, as these joints fail over time. The life expectancy of window and door units may vary widely, from 10 to 50+ years, depending on unit type and materials, exposure, maintenance, types of seals and sealants used at joints, and other factors. Frames that rely on “welding” of joints rather than sealants will generally provide a longer moisture-resistant service life.