Practice exam question - slab on grade capillary break

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    David Rowson

    In essence it's a vapor barrier, I think the wording is akward but capillary movement equates to water withch translates to a vapor barrier which goes between the under slab insulation and the slab itself in cold climates. Might be a case of trying not to use a word or phrase that doesn't lead you to an answer directly but at the same time making you think about the concepts of what they are asking. Also, there is no air break here, it's just graphichs so you can clearly see what they are trying to show. If you try and draw a vapor barrier in a detail and you don't seperate it from the adjacent solid lines, it will get lost when printed, then reprinted, then copied, ect.

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    Michael Doerneman

    I just want to say;  option A is pretty much the only way i've ever physically seen slabs produced.  imagine this as a constructability problem as well.  usually the plastic barrier is the absolute last thing there; and they fill it with the slab ontop.

    That being said;  I think you're missing/messing up the term used.  "capillary movement should be reduced" - this is done by the gravel.  they're basically saying it just needs gravel to separate it from soil.  Soil is notoriously wet... it sucks up water and if it's touching anything the water is going to move though it quickly.  

    And.  i absolutely agree with you.  a capillary brake is a poor term, they should be using the term weather barrier; water barrier; or waterproofing, or even the term "membrane"  is much more "correct" than the term they used.  This exam has some pretty serious errors when it comes to terminology and regional use.  The writers try to make it the most generic phrasing possible.  but it just comes across as unprofessional to me.

    I guess the graphic give away would be generally speaking; a broken line represents waterproofing or membrane layers in most graphic conventions.  that's what made it pop out to my eyes immediately  

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