Originally Posted by
Michael Thomas
Query: would there by any prohibition against installing *two* otherwise correct handrails on the *same* side of the stair with one at a lower height?
As long as the higher one is between 34" and 38" above the line of the nosings (plane of the nosing), no.
In fact, the entire stair wall 'could' be moved in below the handrail, as long as it does not project into the stair width by more than the handrail,
One way to envision this is to visualize the lower part of the wall bumped inward, with the handrail setting on the top of the bumped in part of the wall.
"Stair width" is, after all, measure 'at and above the handrail height' to a height of the minimum headroom - 6'-8", at which point the wall could lean over up to 90 degrees and become a "ceiling".
By the way, "stair width" is measured 'wall-to-wall', 'wall-to-railing', or 'railing-to-railing'.
Which part of the railing? The inside plane of the railing in-fill protection, i.e., to the inside plane of the balusters, glazing, decorative design, etc., ignoring the top rail of the railing, provided that the top rail does not intruded into the handrail space. (I.e., the handrail is at 38" maximum and the guardrail top is at 42", that top cannot intrude over the handrail as it would interfere with being able to grasp the handrail when needed, if needed.)
In dwelling units, the handrail is allowed to be the top of the guardrail as the guardrail height is not required to be 42" high.
The 2001 Florida Building Code, as did the South Florida Building Codes, allowed (in dwelling units) the handrail to be the top of the guardrail provided the handrail was not over 42" high. That allowed for a guardrail of 42" in dwelling units and allowed for using the top rail (if of the proper size and shape) to be the handrail. This is no longer allowed, it was dropped in the 2004 Florida Building Code, and is not in the IRC. Thus, the maximum height of a handrail is 38", meaning the maximum height of a guard in dwelling units, where the top rail is the handrail, is 38".
The guardrail top rail being used as the handrail in dwelling units is why the guardrail on open sides of stairs only needs to be 34" high - the minimum height of a handrail, meaning the guardrail can now be as low as 34" along a stair, the top rail of the guardrail may be the handrail (if of the proper size and shape), and, if the guardrail is higher than 38", the top rail *cannot* be used as a handrail.