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Re: Brick walls on top of gable roofs

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Jim Kestner wrote:

. > Is it the intent of the national codes (UBC '97 2307, BOCA '96 2112.3  and
. > SBC) not to have any masonry directly supported by wood? I also assume
. > that they are refering to vertical support only and not lateral support.
. > What about the case where the masonry is supported by a steel angle which
. > in turn is supported by a wood stud wall? I assume the concern is for the
. > wood supports rotting out if the masonry is in direct contact. What if you
. > are supporting only a few feet of masonry?
. > 


Jim,

I researched this requirement a few years ago to determine if the criteria 
was based on fire destroying the wood.  I was surprised to learn that the 
requirement is purely aesthetic, being based on wood deflection causing 
cracking in the masonry.  (I had a project in which masonry veneer was 
supported by a low slope porch roof of a residence.  Roof sheating was 5/8" T 
& G plywood and roof joists were spaced at about 16" or 24" o.c.  Total 
masonry weight was about 2 tons and the plywood between joists was deflecting 
like a sway back mule.  It was obvious that there was little bridging by the 
masonry.)

With that said, other than supporting masonry veneer in accordance with the 
UBC "exceptions," I would be reluctant to support masonry on wood, even with 
the masonry being directly supported with steel angles.

A. Roger Turk, P.E.(Structural)
Tucson, Arizona