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Unreinforced foundation walls

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Don et al,
     What Stan wrote is true, i.e., calculations indicate that most basement
walls do not withstand lateral soil pressures without vertical reinforcing.
What Don says is also true – in Ontario, the prescriptive part of the code
for houses and small buildings allows up to 8'-0" basement walls without
reinforcing, provided that the soil height does not exceed 7'-7", for an 8"
concrete wall, or 6'-0" for a 10" block wall.
     Many thousands of homes have been built with unreinforced concreted and
masonry basement walls.  However, my experience has been that some of the
masonry block walls do not stand up under certain conditions, e.g., poor
soil, water pressure, vehicle loading.  Consequently, I never approve
masonry walls for basements.  Besides, they trap water in unfilled cells and
leak.  
     I am also careful about long walls and gable end walls in concrete with
little vertical load.
Gary
-----------------
Gary,
     I've seen plenty of non-reinforced HCMU basement walls in Iowa and
Illinois and virtually all of them have a chest-high crack, some opened more
than others.  Realtors used to call me for a report on "sale-pending"
basement wall cracks, but they finally figured out I always say repair is
necessary; and they quit calling.
     Another troubling thing about non-reinforced HCMU basement walls is
that the first course was/is often not a full mortar bed.  The result is
that if water appears on the basement floor in the northeast corner it may
be entering the wall at the southwest corner, no way to know.
     My rule is (and this may have come from a code or something else I
read) all below-grade HCMU should be fully grouted, all cells.  I can live
with that.     
John P. Riley

PS:  Shouldn't the 10" HCMU retain higher backfill than the 8"?       

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