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Tying new foundation to existing

anglycrown's picture

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.

You have to decide whether (post #216327, reply #1 of 3)

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.


Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

You probably need to tie them (post #216327, reply #2 of 3)

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. 

Florida Licensed Building Contractor, 50 years experience in commercial remodeling, new homes, home remodeling and repairs and all types building maintenance.

Yes, DanH is right. (post #216327, reply #3 of 3)

Yes, DanH is right.