The Universal Stair Bracket is designed for both interior and exterior
residential uses, but not for commercial use.
According to the International Residential Code:
"Stairs must be designed for a 40 pound per square foot uniformly
distributed live load. Treads must be designed for the uniformly distributed
live load or a 300-pound concentrated load acting over an area of 4 square
inches, which-ever produces the greatest stresses."
The Universal Stair Bracket allows a rise varying from 6 to 8 inches. The run
varies from 9 to 11½ inches.
Most building codes require a rise of no more than 7 inches and a run of no
less than 10 inches in other than private residential construction. In private
homes most codes allow a rise of as much as 8 inches and a run of as little as 9
Check your state and local building regulations to make sure your
staircase meets local regulations.
Weight tests were conducted under the supervision of experienced
engineers at Stork Herron Testing Laboratories, Inc., an independent
laboratory accredited for ICC-ES reporting. See
tests results. The limit load of the Universal Stair Bracket was
tested to its breaking point based on the harshest conditions and using the
load specifications of the International Residential Code.
Weight tests are conducted under tight parameters.
Ultimate load (using assembly instructions): 1,000 pounds
The allowable download was measured when a vertical settlement of 3mm was
observed on a step secured with Universal Stair Brackets.
Note: Incorrect assembly of the Universal Stair Bracket may reduce the
load capacity. Also, bending of the bracket or deterioration from rust may
also reduce load capacity.