Tuesday, November 16, 2010

Stair Design




Stairs are a challenge to design. The outdoor deck shown is 11 feet 4 inches above the concrete base ( 4 feet by 4 feet by 4 inches deep). The treads are 11 inches wide. The building code states the stairs are to be at most 30 degrees with the ground and the riser height should be between 6 inches and 8 inches. The rise must be the same for all steps. Note that building codes vary by region.
Please find the following.
1. The length of the 2 by 12 used for the stringer. Remember lumber typically comes in increments of 2 feet. Show the design (rise and run) of the stair designed. Include mathematics to show that the stairs are meeting the code of 30 degrees.
2. Where you would place the concrete base so that the stairs rest on the base and at least 3 feet is showing in front of the stairs.
3. Calculate the number of cubic yards of concrete needed for the concrete base.
4. Present at least 2 possible solutions. Explain what the advantages are to each of your 2 solutions.