The correct grade is 12 to one, that is 12 inches of run to one inch of rise or 12 feet of run to one foot of rise. This is the most mechanically advantageous where the amount of horizontal work yields the most efficient vertical lift. Steeper angles take more work to lift the same weight and longer slopes require more horizontal work to raise that load. Sort of the ultimate lever.
A 39 inch rise is pretty long run so, usually they include a turn and a landing, maybe more. Hope this helps. ----- Original Message ----- From: Robert Riddle To: [email protected] Sent: Thursday, August 21, 2008 7:39 PM Subject: [BlindHandyMan] wheelchair ramp I need to build a small ramp from the ground up on to the porch. How do I figure out the gradiant? Like the porch is 39 inches off the ground, how long should the boards be? Ideally the ramp should be cement but I don't know how to do that and it's frankly beyond our budget to have a pro do it. So I'm thinking of building a simple 2 by6 over 2 by 4 ramp and bolting it to the underside of the porch frame. Thoughts? [Non-text portions of this message have been removed] ------------------------------------------------------------------------------ No virus found in this incoming message. Checked by AVG. Version: 7.5.524 / Virus Database: 270.6.6/1625 - Release Date: 8/21/2008 6:04 AM [Non-text portions of this message have been removed]
