What To Know Before Sealing Attic Air Leaks And Improving Insulation

September 29, 2017

Now that summer’s officially over and temperatures are getting more comfortable, it’s a good time to start thinking about those home improvement projects you’ve been putting off, like sealing attic air leaks and improving insulation levels.

Even if you have adequate attic insulation, finding and sealing air leaks air leaks will improve insulation performance and make for a much more comfortable and energy-efficient home.

Attic Air Sealing Benefits

Here are some of the substantial benefits you will enjoy after spending a day or two sealing attic air leaks:

• Save energy and money
• Maintain the desired temperature throughout the home
• Alleviate the dangers of ice dams in winter
• Reduce noise from the outside
• Less dirt, dust, and pests entering the home
• Better humidity control and indoor air quality

But there are some things you should know before you attempt this complicated DIY project.

When to Call a Professional

Although finding and sealing attic air leaks is an intensive DIY project, it’s certainly something that most homeowners can accomplish on their own. If, however, you run into any of the following circumstances, it’s probably best to call a professional to deal with them first:

• Hard to access areas and limited space to work
• Wet and damp insulation, which indicates a damaged roof and other potential problems
• Moldy or rotted woodwork, again indicating a moisture-related problem, possibly exhaust vents
• Little or no attic ventilation
• Old wiring, such as knob and tube wiring, which can cause a fire

Be on the lookout for all of these things when searching for air leaks in the attic. If you come across moisture, electrical, or ventilation problems, contact a professional right away.

WARNING: If you think you may have vermiculite insulation (which contains asbestos), contact your local health department for the name of an approved professional/lab.

What You Will Need

Tools and Materials:

• Large bucket to haul materials
• Dust mask, eye protection, proper clothing (overalls, jeans, hat, long-sleeve shirt), gloves, and hard hat
• Knee pads
• Pen or pencil, and pad of paper
• Tape measure and staple gun
• Utility knife and sheet metal scissors
• Flashlight and/or portable safety light
• Boards to walk on (if needed) – always walk on joists or truss chords, never on insulation or exposed ceiling
• Batt or roll fiberglass insulation and large garbage bags (used for stuffing open stud cavities behind kneewalls and in dropped soffits.
• Reflective foil insulation (or rigid foam insulation) to cover soffits, open walls, and larger holes
• Silicone or acrylic latex caulk and a caulk gun (practice using the caulk gun first) – used for air leaks that are smaller than ¼”
• Special heat-resistant caulk for sealing around your furnace flue and chimney
• A few cans of expandable foam spray for filling gaps and cracks larger than ¼”
• 14-inch wide aluminum flashing to keep insulation materials away from the hot flue pipe

Safety and Planning Considerations:

In addition to this post, refer to A Do-It-Yourself Guide to Sealing and Insulating with Energy Star and The Family Handyman Guide for Sealing Attic Leaks. We recommend reading the full guides before attempting any DIY attic air sealing or insulation projects.

• If you think you may have vermiculite insulation, contact your local health department for the name of an approved professional/lab.
• Gather your tools and have a plan before you start the project. Reduce the amount of trips up and down by collecting all of your tools before you start working.
• Do not work in the attic during hot weather. We recommend starting in the early morning when the attic is coolest. Never spend more than 10-20 minutes in a hot attic.
• Make sure that your household is aware of what you are doing and where you are.
• Wear lightweight, but protective clothing (including a hat, gloves, and eye protection) to keep the itchy and irritating dust, dirt, and insulation off of your skin, hair, and eyes.
• The dust mask should be double-strapped or an OSHA-approved particulate respirator.
• Be on the lookout for nails, screws, and other sharp objects. Always look before you step. We recommend wearing a hard hat just in case.
• Use knee pads. Crawling around on attic floor joists can be painful.
• We recommend using a drop light (aka rough service lights) that you can hook for use in the attic. Also carry a flashlight with you.

Ventilation Concerns

One unfortunate consequence of finding and sealing air leaks around your home is that you could potentially create a situation where indoor air pollutants and volatile organic compounds (VOCs) have nowhere to escape. When you start making significant improvements to indoor insulation, it’s important to call in an HVAC professional to address any potential indoor air quality and ventilation concerns.

If there isn’t enough ventilation in your home and attic, a professional technician may recommend adding ventilation fans to flush out stale air and improve indoor air quality.

To make sure that your heating system is properly venting to the outside, it’s important to schedule annual heating maintenance every fall from a professional HVAC technician.

Any time you make significant improvements to your home’s insulation levels, we highly recommend calling a professional HVAC company to inspect your home for proper ventilation levels.

How Much Attic Insulation Do You Need?

If you can see your attic floor joists, you probably need to add some extra attic insulation. But before you start thinking about increasing attic insulation, measure it to make sure. All you’ll need is a ruler or yardstick, gloves, and a dust mask.

Watch this video for more information on measuring your attic insulation: