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Re: Sunroom Anchorage

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I treat sunroom framing just like any other prefabricated portion of the
structure. Structural calculations and drawings are done by the manufacturer's
engineer after I advise them of the governing code live load and wind or
seimic load. I use the end reactions from their calculations and design my
part of the building for these forces. 

For the pony wall, if it is wood stud, I add a steel angle or channel every 4
to 6 feet embedded in the footing, bolted to a double cripple stud, with a35
clips to a dbl top plate. Or I use masonry wall.

The existing building framing should be analyzed to resist the forces at the
top of the sunroof framing. If the horizontal load occurs between the top and
bottom of the wall, check the wall studs to see if it is still OK. Remember
that the wind load is still the same on the wall, the wind load on the lower
wall portion is just gone and is now concentrated at the top of the sunroof.
If the horizontal load is at the gable end truss of the building, add diagonal
braces every 4 to 6 ft from the point of horizontal  load to the roof framing
to transfer the load to the roof diaphragm. 

If diagonal bracing to exixting roof is not acceptable, use ledger/beams
spaning horizontally with the reaction at ends of beam span resisted by full
height vertical posts from floor to roof. 

Your projects seems complicated. Like Dennis, I can't picture what your
sunroof looks like relative to the house. But the main thing is, if the
sunroof is not significantly higher than the house, there is no additional
wind load to the existing house(theoretically). So if you can transfer the
lateral reaction force on top of the sunroof due to wind load(which probably
govern vs seimic load) to the roof diaphragm, you don't need to add a new
shear resisting system.

Unless the lateral reaction you are talking about is due to vertical dead and
live load acting on the sloping sunroof framing causing a kickout force. Then
you got to design a new shear resisting system for this new lateral load.

Hope this helps.

Ernie Natividad