concrete stairs with side walls

daleinpg

My 1929 house has dramatic 9' wide stairs leading to the front porch. As you will see from the pics it needs to be replaced. I guess rebar was hard to come by in 1929 due to the depression, so they used scrap iron. I got a permit from the city to "tear down and replace" so I won't need to build the 36" landing required by new code, though I will need railings. They are 5 1/2" rise, 13" tread with 9 steps. The tallest wall is 40" above grade. Under the stairs is hollow.

I just really want to build the same thing. I plan to corner my local inspector to ask about footings for the walls (depth and width), but I am having a bit of difficulty wrapping my head around building forms that are strong enough and of the right shape to do this in one pour. I can find things about building walls, and things about stairs, though they all seem to be sitting on dirt rather than suspended.

Do I need to do 2 pours? How thick does the concrete need to be between the back of the tread and the under side of the concrete?

Any sugestions or advice would be appreciated.

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jomama45

Do the new steps really need to be suspended? It would be far easier having them sit on grade from a logistics standpoint.

As for forming and pouring in one pour, it would obviously be easier if you didn't need the sidewalls, but it can be done either way. You would cut a form for the inside that would be similar to a stair stringer, but set upside down. The form for the exterior of the wall would be far simpler. Keep in mind though that if the finished exposed product is going to be concrete, you'll need to strip all of this out & finish it all before the concrete sets completely. Easier said than done. If you would plaster the walls (like they are existing) and consider settign brick pavers, cut stone, etc.... for cladding on the risers & treads, the concrete pour itself would be easier to complete, although you'd have quite a bit of additional work to finish the steps off.

daleinpg

I thought about pouring the stairs on top of the debris from the tear-down, but I would need to build a retaining wall at the back side of opening under the stairs first. It is quite a large opening under there.

I also considered building the side walls out of block, but block walls just never look like concrete walls, and then there is the problem of tying the wall to the stairs. We don't want to put any kind of stucco, stone, brick or finish on the walls or the stairs. Plain concrete would look best with our house style. I see your point about getting it all finished as it sets up. A lot of area and not easy to reach. Might have to go back and surface it. I am sure there will be small voids no matter how hard we vibrate or bang on the forms.

Thanks for the input.

Mort

Boy, a mono pour with all that would be tough. If it were me, I'd do the walls and footings in one, the stairs in another.

You would only need to suspend the stairs if you wanted something under them, and it doesn't look like you do. As far as filler for under them, any old thing will do. I've seen guys use a hay bale before. You aren't going to park a truck on it, after all.