Air Sealing a Basement

Air Sealing is an Important Step

Does Air Sealing your basement save money?

Air Sealing your basement a worthwhile investment!

Adding insulation to your basement is one of the most cost effective investments you can make for your home. It can and will expand your living space, increase your comfort and the value to your home. In order to make the renovation worthwhile, there are a few important things to consider before you start.  Avoiding costly mistakes with your investment by addressing all mold and moisture issues and that means you will have to air seal your walls. More information about Air sealing and saving energy.

  1. Air Sealing The Basement Rim Joist
  2. Energy-Savings-Makes-Cents


Water- Gas – and Mold. Oh My!

Basements are often dark, moist, spider ridden dungeons- the perfect place for scary story telling. Basement stories are like, “The Wizard of Oz”- there are a lot of scary and strange things in a dark place. If you stay the course and do the right things there is a wonderful world of extra space and a beautiful playland for your kids.

You should prep and clean your walls. This means removing any dirt, debris, loose paint or anything else that may disrupt a wall’s surface. This does not mean a hospital grade cleaning, use your judgement and remember we are as good as the surface you glue to. Cleaning the walls also helps prevent future mold and mildew issues by removing dust and pollen from the wall surface. Mold grows on concrete because of the organic components like dirt and dust that stick to it. 

More reasons to clean your wall – dust and pollen!

All surfaces contain the presence of dirt, dust and pollen, mold is able to thrive on almost any surface given just the right conditions, when moisture is present. Mold needs water, food, oxygen, and an environment between 40-100 degrees F to thrive. Basements often provide the perfect home for mold.

Mold needs food.

Bread Mold in a Basement

(Note that in the above picture the bread is moldy not the plastic bag.)

Mold grows on concrete because of the organic components like dirt and dust that stick to it. You can protect against these issues and ensure a strong adhesive bond by thoroughly scrubbing your walls with a masonry cleaner such as Trisodium Phosphate (TSP) mixed in warm water. Mold is an opportunist and will decomposes organic material, as soon as there is enough H2O.  Therefore mold grows very easily on organic material such as bread, wood and the paper on drywall. The mold spores will start growing within 24-48 hours make sure you seal the wall with spray foam to seal the air leaks. So it’s important to act fast when dealing with a water problem or air leaks in your basement and to build with materials that provide zero nutritional value in which the mold spores to survive.  Essentially for the best and healthiest basement  control the air, moisture and food supply.

Do the air channels in the back of the panel dry the concrete wall?


The channels in the back of our panels are not meant to air dry the concrete wall. Unfortunately you don’t choose the air that would move through a wall system. The air can transport dust, pollen, viruses, and with it dust mites.

House dust mite, Dermatophagoides spp.  Photograph by: Acarology Laboratory, Ohio State University.

It’s not good building practice to use vapor barriers with wood framing below grade moisture problems are inevitable. When the wall happens to get wet for any reason, the vapor barrier prevents inhibits the materials that got wet from drying. InSoFast is a Class III vapor barrier that does not retain water(it’s plastic) yet it will allow drying to the inside so vapor/moisture, pressure will not build up. With that said we still want you to air seal the InsoFast panel at all penetrations, at the floor and top of the wall. The drainage channels are not air drying channels, they are gravity powered drainage channels. To recap, you want to limit dust filled moisture ladened air from coming into contact with the cool concrete. The channels on the back of our panels are gravity drains and NOT air channels. Seal them off.

The top 6 areas to make sure you air seal

InSoFast panels have no food value and the panels are considered a 2″ or 2 1/2″ thick insulated vapor/AIR barrier that will not to support mold growth. So here are the top 6 areas to make sure you air seal.

  1. The TOP of the wall.
  2. Along the floor line.
  3. Inside corners.
  4.  Around any window openings.
  5. Openings like air registers.Air sealing
  6.  All service openings like electrical boxes.

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