I am putting in footings for a garage and find i will need to step them to follow the grade. I have a few questions on the requirements for this.
1 What is the required overlap for each step?
2 Is there a required distance from a corner for a step?
Thank you for your response on this
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Local code will dictate what is required. I usually step the concrete to fit your panels. Here we are allowed only 2' in height steps.
Why the 2 ft. maximum? I've never heard that one before, and in NJ, where I used to build, we routinely stepped down 32 in. to 48 in. from the garage footing to the house footing.
Curious,Andy Engel, The Accidental Forum moderator
It's a question of horizontal continuity, with limitations on vertical stepping intended to preserve that horizontal connection, with tied rebar through the step. Otherwise you get displacement in the foundation due to lack of continuity (especially if soil conditions are slightly different between each step - of course the taller the step the greater the likelihood that differential soil conditions will be encountered).
In some cases it's ROT, in some actual code. The bottoms of the footings should not exceed a 2:1 slope and the 2' maximum step is a good idea too. I prefer to see no more than two courses or 16", generally with each step. For a stepped footing on sloped grade, vertical steps should be less than 75% of the horizontal distance between the steps, which should be a minimum of 24". Concrete in the vertical part of the step should never be less than 6" thick and preferably the full width and thickness of the footing.
T. Jeffery Clarke
Quidvis Recte Factum Quamvis Humile Praeclarum
Edited 7/1/2002 9:50:30 PM ET by Jeff Clarke
Jeff, I don't think I ever got the concrete in the vertical part of the step to be less than 10 in., and frequently, it was closer to 2 ft.! I never encountered differential soils where I built in north Jersey. Once the topsoil was stripped, mostly it was glacial till, deep clay-loams or simply bedrock. And I never poured a sloped footing. Andy Engel, The Accidental Forum moderator
Hey Andy, Where is the Accidental Forum that you moderate? Sounds intresting....
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The previous post said it well enough. But here in the South Bay of So. Ca. most cities have no min. step amount, But I would step only when I had to to keep the min embedment, for concrete, and / or 1/2 block exposed. Here we can slope our footings 1 ft. in 10 ft. But on a slope I try to keep them as level as possible.
It is OK to step at the corner as long as you get minimum embedment and clearances for anchor bolts and hold down bolts. The steps should follow the grade keeping a minimum of 8" above grade .
The trench should be terraced parallel with the steps in the forms and never be sloped. Sloping the trench makes hanging the rebar easy but I think it's cheese. The trench should only be sloped at the transition between steps to get ground clearance for the rebar.
Try to make the runs as long as possible between the steps. Steps heights are dictated by the material used. If you are using 2x10 for forms, the the step increments are multiples of 9.5"+ or -.
Mike