Insulation & Air Sealing - Let's Talk About Basements - Common Problems Along with Solutions

This article was written by Halco owner, Hal Smith, and published in ACCA's newsletter, IE3. Please click here to visit the original publication. 

When air sealing and insulating a home, you should always give the attic first priority and then go to the basement. As a member of Dr. Energy Saver, they teach the simple ABC’s of Home Performance:

#1 A- Attic

#2 B- Basement or Crawlspace Below

#3 C- The Conditioned space in-between

Today we are going to talk about the basement. Most of the basements in our service area are semi-conditioned with typically the boiler or furnace there. 90+% of the homes in our market place have basements. When we look at the basements we typically look for the following:

Walk Out Basements

We have many very old homes in our service area. A lot of them have walk out basement doors. Most of the doors are old tongue & groove boards with cross bracing. They are not insulated, or weather stripped at all. We have developed a universal fit insulated door option that we use in most cases. Sometimes we need to custom order a size. We have not had great success trying to insulate and weather strip the existing door.

Rim Joist

Rim Joist areas are a very common place to insulate and air seal. Our company does this with spray foam typically. Many times, we pull out the fiberglass batt to do this.

Windows

There are many basement windows in the older homes that are in very bad shape and leak like a screen door. We have developed a system to quickly and economically replace these with a universal fit system. We also offer custom replacements as well.

Basement Walls

We first focus on the above grade walls because that is the area of the biggest loss. Many times, it is also worth while to insulate the entire wall. With old stone walls we have good success spray foaming them then spraying a thermal fire barrier. Sometimes with water problems we will first use a drainage matting fastened to the wall, connecting to a basement drainage system before we spray foam. With block or poured walls depending on how much stuff is on the wall we will use Thermax insulation board with the thermal barrier already in place. Other times we will spray foam the block or poured walls.

Chase ways, piping & electrical openings

It pays to seal all these openings. Many times, they are pathways right to the attic increasing the stack effect of your home.

Overhangs & Cantilevers

These areas are fairly common, and most times not properly insulated or air sealed.

Properly Vented Gas Appliances

Part of our job is to make sure all gas appliances are properly vented and continue to vent during a worst case draft test. We try to eliminate gravity vented appliances whenever possible. We find many clothes dryers in the basement that are not properly vented to the outside. We also check for combustion gas leaks on all gas piping. As well as testing the CO level in the exhaust of fossil fuel appliances.

Controlling Moisture

It is very important to do everything possible to control moisture in a well sealed up home. In the basement we look for open sump crocks and dirt areas that need a vapor barrier of some sort. We also keep an eye open for wet basements. Some wet basements can be solved by regrading outside or having a properly operating rain gutter system. There are other times when a complete basement drainage system is appropriate. Sometimes a high performing central dehumidifier is needed to control moisture in the home.

Radon Test

We try to encourage customers to do an inexpensive radon test. Sometimes people have radon problems and don’t have any idea about it.

Summary

When we perform a comprehensive energy assessment for a customer we end up spending a fair amount of time in the basement. At Halco we perform over 2000 comprehensive energy assessments a year. This provides us plenty of work fixing all the problems we uncover. Again, we do the most effective work typically in the attic but a close second is the very worthwhile work in the basement. Don’t hesitate to reach out to me with any questions.