Attic Moisture
Sources of Moisture
Exhaust Appliances
Moisture in the attic may be coming from multiple places. Commonly bathroom exhaust fans are vented directly to the attic. Sometimes they may be vented to attic intake ventilation. Bathroom exhaust fan carry large amount of moisture and if they are vented into the attic space they will dump all the moisture into the attic. The same goes for exhaust fans that are vented to the soffit area. As air from outside gets sucked into the attic from the soffit vents it may be pushing the bathroom exhaust moisture into the attic. All exhaust appliances must be vented to the outside. Exhaust appliances should never be vented to the soffit or roof vent but always through such ventilation option.
Home Heating
While heating your home and trying to remain comfortable during the frigid winter season, you may be introducing a great deal of moisture in your attic. When homes are built, the framing gaps and cracks are often left exposed and unsealed. Holes are drilled to allow the circuit of electrical wiring and plumbing pipes to be ran throughout the home for much needed services. These holes, gaps and cracks are also known as bypasses or penetrations. As the temperature increases the air in the living space rises. This is a natural occurrence known as stack effect. Warmer air is able to hold more moisture than cooler air. As this warm moist air rises through all the hidden bypasses it enters the attic. Once the warm moist air enters the cold ventilated attic (usually the same temperature as outdoors) it comes in contact with the cooler surfaces and starts to condense (sweat). The moisture can lead to serious problems. Roof rafters and joist may start to rot. The underside of the roof deck may weaken and have a reduced life expectancy. Staining, discoloration and mold like substance may start to form on surfaces.
Stack Effect
Vent Exhaust Appliances
Attic Air Sealing
Repair any Roof Leaks
Health & Safety
Controlling Moisture Source
Controlling attic moisture is imperative to the healthy and safety of your home and the occupants living in them. Moisture in the attic can cause structural issues, diminished building materials and increased energy consumption. Contacting an energy auditor and having your home evaluated will be the first step in correcting these issues. Controlling moisture in the attic is a step you will want to take as soon as possible as minor issues can turn into big problems over a short period of time.
