Construction Tolerance

Where codes or regulations establish minimum or maximum values and allow no tolerance outside the limit, industry standard construction tolerance should be incorporated into the design. For example, concrete ramps that must comply with "zero tolerance" maximum slope requirements for wheelchair accessibility should be designed at less than the maximum slope, such that allowable construction tolerance for concrete surfaces will not result in a slope that exceeds the maximum for wheelchair accessibility. If the maximum slope for wheelchair accessibility is 1:12, a design slope of 1:13 (or 0.95:12) may provide sufficient tolerance for construction to meet the slope regulations.

Zero Slump Concrete

After a few of us had taken the architect license exam, we were talking about the questions. One of the multiple choice questions asked how long to wait before removing the cone during a concrete slump test. My colleague had chosen answer "c. 3 days".