Attic moisture problems often accompany excess attic heat. Both may damage your home’s structure, and ruin any possessions that you store in your attic. Furthermore, attic moisture can degrade your insulation, and reduce your home’s energy efficiency. Indeed, attic moisture issues can be costly, so you need to learn how to control the moisture before it causes a problem.
Most moisture in the attic comes from air migrating from the living spaces below. Water vapor in warm air rises with the air. Because conditioned areas of a sealed home have slightly higher air pressure than a vented attic, air will escape rooms, and enter the attic through any available cracks, gaps or openings. The key to controlling attic moisture problems is sealing air-access points. Here are five guidelines for shutting off the flow of moisture into your attic:
- Stuff plastic bags containing pieces of fiberglass insulation batts into open stud cavities that lead into walls. Additionally, add these bags to large voids in dropped ceilings over kitchen cabinets, light fixtures and where walls meet the ceiling.
- Apply standard silicone caulk to close gaps at penetration points where electrical wiring enters the attic. Locate the backside of ceiling electrical junction boxes that protrude into the attic. Seal around the perimeter of the box with silicone caulk, and seal the small access holes in the back of the junction box.
- Caulk around the openings where plumbing vent pipes, and bathroom and kitchen exhaust-fan ducts, pass into the attic. If the gaps around these surfaces are too large for caulk, you can use canned expanding foam.
- Seal around furnace flues or water-heater vents by using aluminum flashing combined with high-temperature silicone caulk.
- Insulate and seal your attic hatch or pull-down stairs door. Cut a piece of rigid foam insulation the size of the hatch or the stairs’ door, and affix it to the backside. Use adhesive-backed foam weatherstripping to seal the gap between the door and the door jamb on all sides.
Roth Home & Cooling is Portland’s full-service heating and air-conditioning company. Since 1976, we’ve built a sales and service track record of customer satisfaction. Call us at (503) 266-1249 for more advice about attic moisture problems or other home-comfort issues.