Caulk and block method for thermal shell details (C) Daniel Friedman Vapor Barrier Details for Sealing at the Band Joist

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Band joist - rim joist vapor barrier sealing details:

This article describes how to install vapor barriers and how to avoid problems with building indoor condensation: we provide details for caulking, sealing, & insulating at the building band joist or rim joist will protect the integrity of the building's thermal shell.

Multiple approaches to building vapor barrier sealing details are provided to address this air and moisture leak problem: the caulk and block method to seal the rim joist is effective but time consuming; offsetting the band joist to permit exterior rigid foam insulation is described; details are provided for sealing building overhangs such as found on a raised-ranch home; other building air leak sealing methods developed by researchers at the University of Toronto are described.

We also provide a MASTER INDEX to this topic, or you can try the page top or bottom SEARCH BOX as a quick way to find information you need.

Vapor Barriers & Building Condensation - Sealing the Band Joist at Building Floors - part III

Vapor and condensation table (C) Daniel Friedman

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Sketch at page top and accompanying text are reprinted/adapted/excerpted with permission from Solar Age Magazine - editor Steven Bliss.

"Dealing with Band Joists. Don't let them sabotage your thermal shell" - links to the original article in PDF form follow the expanded/updated online version of this article just below.

Traditional Methods for Sealing the Building Rim Joist or Band Joist

Part 1 of this article on building details to seal air and vapor leaks at the band joist or rim joist describes two traditional, effective, but labor-intensive methods to stop air, moisture, and heat leaks around the perimeter of building floors and overhangs.

Better Methods for Sealing the Building Band Joist

Floor overhang sealing and insulating details (C) Daniel Friedman

Insulating and sealing details for cape cod design homes (C) Daniel Friedman

Building sealing without poly vapor barrier (C) Daniel Friedman

For details about use of acoustical sealants or tapes to seal polyethylene vapor barriers, see ACOUSTICAL SEALANT CHOICES.

Here we include solar energy, solar heating, solar hot water, and related building energy efficiency improvement articles reprinted/adapted/excerpted with permission from Solar Age Magazine - editor Steven Bliss.

Original article in PDF format

This discussion of vapor barriers and condensation in buildings in this article series begins at

  1. part I, VAPOR BARRIERS & CONDENSATION in buildings, (when and why condensation occurs inside buildings, explains the problems caused by excessive indoor condensation, explains how moisture enters building wall and ceiling cavities, and summarizes the best approaches to prevention of indoor moisture and condensation problems),
  2. continues with part II at VAPOR CONDENSATION & BUILDING SHEATHING (detailed questions and answers about various building wall sheathing and insulating materials and their impact on building condensation problems)
  4. Readers should also see VAPOR BARRIERS & HOUSEWRAP.

House Wrap, Air & Water Barrier Articles


Continue reading at VAPOR BARRIERS & CONDENSATION in BUILDINGS or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.



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Publisher - Daniel Friedman