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Tying new foundation to existing

anglycrown | Posted in General Discussion on October 24, 2018 04:51am

Existing foundation on left, addition to be on right.  Existing not down to frost line, addition will be down to frost line. Not built yet.  Soil is decomposed granite, rocky, drains well.  Addition is single story, as is existing cabin.  Gable wall to gable wall.  Best way to tie these together, or isolate the two?  Thanks in advance.

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Replies

  1. DanH | Oct 24, 2018 06:32pm | #1

    You have to decide whether you want to tie them together or isolate them.  If the soil were clay or loam then a frozen foundation would produce significant heave, and if the foundations were tied together there would be serious damage.  Hard to say in your specific conditions.

  2. florida | Oct 25, 2018 01:48pm | #2

    You probably need to tie them together to stop the addition from pulling away from the older part. Rebar in drilled holes and epoxied in place is the standard technique. Your mason can tell you more. 

  3. JosephNelms | Nov 10, 2018 12:15am | #3

    Yes, DanH is right.

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