Tall Wall Definition

[CANeng11]

We were having a discussion in the office about whether this specific situation should be deemed as a tall wall: entry of a house is open to above to the second story on the inside but on the outside there is a small roof over the front entrance porch midway up the wall. The argument is that the roof at the front entrance will provide lateral restraint for the front entrance wall and therefore should not be classified as a tall wall, which would require engineering.

What are your thoughts?

 

[CANPRO]

Does the roof provide lateral restraint or does it create an additional lateral load on the wall? The typical arrangemt I’m picturing wouldn’t provide any restraint to the wall. Sketch would help.

If you’re relying on the roof to brace the wall, that sounds like it wouldn’t fall within prescriptive codes and would need an engineered solution anyway.

 

[JAE]

The small roof also needs to have some means of being laterally braced - by a braced wall line on each side perhaps.

If the small roof depends on the wall to keep it laterally in its place, and the wall depends on the small roof to laterally brace it into a non-tall wall condition, then you simply have two drunks leaning on each other.
Not a good structural system I've heard.

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[OldBldgGuy]

Many, if not most, small roofs over front entries are wider than the tall wall of the stairwell so they meet the 2nd floor diaphragm or they are in line with the interior partitions at each side of the interior stairway, which means they are not dependent on the tall wall for bracing. In my experience it would be unusual if the roof didn't provide lateral restraint.