Our top question from yesterday was about how to accurately show the bottom of a wall system that included an insulated rim joist.  We like to discuss questions our clients have every day and dig into the deepest detail of REScheck reporting here on our REScheck blog.

The rim joist is the area that sits around the perimeter of the top of the foundation.  For many years, this area was neglected and left under insulated.  This cost American homeowners millions of dollars, and caused drafty floor systems all because the rim joist was forgotten.

On a rim joist their should be a band of insulation equal or greater to the insulation in the wall system above it.  Once this insulation is in place the REScheck report is very simple, but very often forgotten.  If you have a 12″ tall floor system like a conventional 2x12 then you would add this to the height of the wall when calculating the wall’s square footage.  So if your wall was 8′ tall and you had a 1′ insulated rim joist the actual height of your insulated wall would be 9′.

Entering the rim joist correctly into rescheck is very important, but so is making sure that the actual insulation is installed correctly once on site.  Failing to insulate a rim joist around the perimeter of your home properly would be the equivalent of cutting a window hole in your living room and never installing a window.  It would not rain in, because there is a low R-value conventional lumber covering the gap.  However this uninsulated rim joist would leak energy in humongous amounts.

The rim joist sits at the top of a basement or crawl space foundation and acts as the joining band of the foundation to the wall system.  This area must be insulated and REScheck has a special system of making sure it is included in the calculation.  If you have any trouble entering your insulated rim joist feel free to give us a call.  865-235-6277.

Have you had a rim joist in a home that was not insulated?  What types of issues did you have?  Did anything change with your power bills once you insulated it?  We would love to hear your story on Houzz, Pinterest, Google Plus, Tumblr, Blogr, Twitter, or Linkedin.

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