Hi Aaron,
The only times I have seen more specificity has been on contract documents such as drawings, details, and specifications.
In those cases what I've seen specified has been ' minimum 1/8 inch per foot slope ' and sometimes that is accompanied with ' maximum 1/4 inch per foot slope '.
Those are based on the widely accepted minimum surface drainage slope of 1/8 inch per foot and that any slope greater than 1/4 inch per foot (either in the direction of travel - i.e. "running slope", or perpendicular to the direction of travel - i.e. "cross slope") of a walking surface is potentially a hazard to persons using the walking surface.
I have not yet found a code which specifies a maximum slope, other than for accessibility purposes (i.e., in the ADAAG - place cursor over link, right click, select 'Open in New Window':
http://www.access-board.gov/adaag/html/adaag.htm ), which specifies a maximum slope of:
- 4.3.7 Slope. An accessible route with a running slope greater than 1:20 is a ramp and shall comply with 4.8. Nowhere shall the cross slope of an accessible route exceed 1:50.
A slope of 1:50 is approximately equal to 1:48, and 1:48 is 1/4 inch per foot. Balconies would need to meet the 1:50 maximum slope for either direction as people could be walking either direction where accessibility is addressed.