Discover Attic Problems - The Life Cycle of an Attic
Before identifying attic problems, it is important to understand the life cycle of a typical attic. After all, attics and basements/crawlspaces are the greatest source of a home's heat loss.
Improving these spaces are among the most valuable energy, comfort and market value investments you can make in your home. Air leaks make your house drafty and uncomfortable and raise your energy bills. Attics can waste more than 30% of a home's heating and cooling energy.
When the air you have paid to warm rises from your furnace, it sucks in cold air from all around your house, through the windows, doors, and any holes or gaps in the basement, walls, sofits, plumbing vents, lighting, etc., causing a "chimney effect"; the reverse is true for summer time. Finding these leaks can be very difficult, especially when they are hidden under existing insulation.
Air, Moisture and Attic Problems
Two things to keep in mind about air and potential attic problems(though both are technically the same thermodynamic principal): 1. warm air rises, and 2. air travels from hot to cold (“nature hates a vacuum”).
In a house, as warm air rises, it picks up moisture from people, bathrooms, laundry rooms, humidifiers and the kitchen. Once moist air flows upwards, the moisture condenses on the colder surfaces and resulting in these attic problems:
- Your home heats up in the summer (sometimes reaching above 130 Deg F or 54 Deg C) and cools down in the winter too fast, and it always feels drafty, while your energy bills are always high,
- As the wood joists, rafters or plywood get wet, they expand. In the spring, the wood dries and then contracts and goes through the cycle again. This constant heaving loosens the nails and causes the roof shingles and the roof to buckle.
- Ice damming also happens when the warm air enters the attic in the winter, especially if the ducts are poorly insulated or unsealed. The heat causes snow on the roof to thaw and reach the colder areas near the sofit, where it refreezes, and creates a dam. The dam causes the water to gather underneath and back up under the shingles, and the roof warps and buckles.
- Untreated, moisture can lead to mold and mildew with serious health problems and also causes the wood to rot and to lead to, yes(!), roof failure.
Apply These Principles
How can you deal with the space in the uppermost level of the house efficiently, so that it will be the asset it was meant to be and not the liability it can so easily become?
Separate the unconditioned space from the rest of the house, and Weatherize, Insulate and Ventilate (WIV). Sounds pretty non-intuitive to insulate and ventilate at the same time? Here’s what you get if you WIV:
- In the winter, the insulation will keep the attic cold and natural ventilation will reduce ice damming and moisture since, the temperature up there is close to outdoor air temperature.
- In the summer, the insulation will resist the heat from getting into the conditioned cool space inside, and natural ventilation will draw out the hot air through the vents or bring in cooler outdoor air.
Never Block Airflow
It's important to make sure that your vents in the eaves, soffits, rafters and ridge are NEVER blocked and have air flowing freely. Proper ventilation goes a long way in eliminating potential attic problems before they arise.
If you have very hot summers, and don’t have central air conditioning, you might want to consider an attic fan. If you absolutely need to use a fan, use attic solar fans, which turn on when the sun is out (usually the warmer time of the day) using PV panels (free electricity) and have a temperature sensor.
But cool as all these devices are, I still think that natural ventilation, when designed and executed properly, is the way to go.
One more note about moisture: moisture generally comes from living spaces, crawl spaces and basements. So while planning to weatherize, take a whole house approach and seal your basement or crawl spaces (foundation), ducts, windows, doors, lighting receptacles, outlets, soffits, and any other openings and gaps where you can feel a draft.
Where to next? Assess your attic
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