# concrete stringer questions



## Bondo (Dec 8, 2007)

Ayuh,... Use lots,+ lots of reinforcing Steel....


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## DangerMouse (Jul 17, 2008)

this is a rough sketch of what i had in mind. how should i run rebar?
i want to use a 55g plastic barrell to get a beveled curve at the bottoms. that should make it a bit easier to keep it swept out underneath, yes?

DM


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## Bondo (Dec 8, 2007)

You gonna pour the piece, then attach the field stones,..??

If you tied the anchor bolts to a rebar grid,+ a wire mesh cut-out,...
I'd think it'd hold up for a Good Long Time...


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## Willie T (Jan 29, 2009)

Because everything underneath is going to be hidden by the treads anyway, I hope you aren't setting yourself up for a ton of unnecessary work and headaches.

Have you considered simply laying up regular concrete blocks in the same shape you drew the formed piece?

Pour a footing, lay the blocks (leaving the sides set back in enough to later mud on some field stones), pour the blocks with concrete, and drop in some anchor bolts for the treads.

A fairly straight-forward, and kind of easy job. Sure beats hassling with forms, and wrestling with a couple of hunks of VERY heavy and unwieldy concrete... that will be difficult to get into place both level and plumb.

The huge formed stringers would also require a footing, just like the easy-to-handle blocks.

BTW, the blockwork is not hard to do in an arch like that. You just form a piece of plywood to that shape, and lay the block as close to it as you can. The concrete pour fills in the blanks after you mud the sides solid.


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## DangerMouse (Jul 17, 2008)

thanks for the responses.. i had thought to begin with about using blocks, but wasn't sure if the stones would hold up.
i already have the footing the O/O has down. 
i was planning on pouring the piece right next to where it goes, and then setting the stones into the wet concrete. then tipping the whole thing upright in to place once set up. i'd like to keep it 'open' underneath so she can sweep easily and small critters won't use the space under as a hiding place or nest.

DM


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## Willie T (Jan 29, 2009)

Well, do keep in mind that you're creating one HEAVY installation to tilt up and get into place.

Concrete weighs about 4,000 pounds per yard. And if you round out one of those stringers to somewhere around 3' x 3' x 8", you've got almost a quarter of a yard.

Then add the rebar at perhaps 200 pounds... then the stone at the same weight, and you're talking almost 1,400 pounds per stringer. Frankly, only 500 pounds would be a tough job to wrestle into place.


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## DangerMouse (Jul 17, 2008)

i agree, i think i should do it in blocks, then fill in and set rods that way.
do you think i can get the same general shape if i use blocks, then fill it in? 
how well do you think the stones will hold up if i just use concrete and stone up the outsides?
i guess if any fall out, i can just use PL and glue them back in for another 50 years.... lol

DM


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## Willie T (Jan 29, 2009)

i agree, i think i should do it in blocks, then fill in and set rods that way.
do you think i can get the same general shape if i use blocks, then fill it in?
*I don't see why you cannot get exactly the same shape. True, you may have to trim some of the blocks to get exact heights and tread base widths, but that's easy with a masonry blade on your skill saw.*

how well do you think the stones will hold up if i just use concrete and stone up the outsides?
*Just about every house you pass in those fancy subdivisions (and commercial construction, too) has their stones "mudded" onto concrete surfaces. Same thing with millions of fireplaces throughout the USA.*

i guess if any fall out, i can just use PL and glue them back in for another 50 years.... lol

DM


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## Willie T (Jan 29, 2009)

Here's how it would look with 8" x 8" x 16" blocks. You can use smaller size blocks, but the cost of special size blocks might not be worth it.

All sealed up like this, there would be no need to leave the arched opening, as no dirt nor animals would wander beneath it.

On the bottom I show how each end of the pre-cast beams (they come in a handy 40" length) and blocks need to be notched with the masonry saw to allow for a continuious concrete and rebar bond. All you need to make are the two blue cuts... the red section will knock out with a sharp hammer blow.

And, of course, the ends need to be formed over with plywood for the pour............. This can easily be done with a long bar clamp holding the two ends against each other on each beam, no fuss, no muss, no nails.

For this, as shown with four levels, you'll need 34 regular blocks, 8 "half" blocks, and four 40" precast lintel beams. You can form and pour your own treads and top slab.

BTW............... For an application like this, since you will be pouring all the cells solid, you can either "dry stack" the blocks, using no mortar at all... or you can use minimal mortar joints. The reason for this is to maintain as short a riser height as possible. Fat mortar joints tend to take your heights into the illegal realm. But a standard block is 7-5/8" high, and therefore makes a perfect step height if you don't blow it with big mortar joints.

The average mortar joint is 3/8". This, added to the 7-5/8" of the block makes for a full 8" inches of rise. Not a good idea when the inspector puts a tape on it. And remember, your first course of blocks has to be either a couple of inches down in the earth, or the whole course be cut off a tread thickness in height.


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## DangerMouse (Jul 17, 2008)

nice sketches, thank you for taking the time. i only need 2 steps up to the landing though, so that is less blocks, and i hadn't planned on any blocks along the back either, just 2 'columns' to take the steps and railing mounts. i suppose i should 'fess up. the reason i want it hollow underneath, no stair facings, and the archways is for my dog. she loves it under there right now and i so hate to disappoint her.... i also planned to slip in a chain ring. she's not quite trained enough to let her roam free like my other dog. he knows his yard and stays in it.

DM


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## Willie T (Jan 29, 2009)

DangerMouse said:


> nice sketches, thank you for taking the time. i only need 2 steps up to the landing though, so that is less blocks, and i hadn't planned on any blocks along the back either, just 2 'columns' to take the steps and railing mounts. i suppose i should 'fess up. the reason i want it hollow underneath, no stair facings, and the archways is for my dog. she loves it under there right now and i so hate to disappoint her.... i also planned to slip in a chain ring. she's not quite trained enough to let her roam free like my other dog. he knows his yard and stays in it.
> 
> DM


I'm laughing. I think I already knew that. My dog just loves crawling up under my pickup whenever I'm out in the yard. It's shady, got the good oil smell, and he can watch me.

But as I said, arches are not difficult to form and pour... although that will make "dry stacking" pretty problematic.

On new steps, you will be subject to current codes. Make sure the inspector will buy having the riser fronts completely open. Sometimes they require you to block in at least enough of them so that a foot (or a toddler's head) cannot get caught under there.


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## Willie T (Jan 29, 2009)

Here's an idea. Of course, with one less step, your side lintel beam would be at the top.

The first step lintel beam has also been replaced with blocks turned on edge for a doggie view port.


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## Willie T (Jan 29, 2009)

How about this one?

Correct number of steps
Smaller upper slab (The bottom view has an 8" shorter top slab.)
Less blocks
Opening in the back and on both sides
Doggie viewport in the front
And you can even form an arch in there with plywood if you want.


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## Phuture (Mar 17, 2009)

willy. my compliments on your drawings. if you don't mind me asking... what software did you use? once again nice work. :thumbsup:


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## Willie T (Jan 29, 2009)

Phuture said:


> willy. my compliments on your drawings. if you don't mind me asking... what software did you use? once again nice work. :thumbsup:


Thank you. But it was really nowhere as difficult as it might look.

The program is a free one from Google. It's called "SketchUp". Truthfully, almost anyone can put this program on their computer, and be doing drawings like these in well under a week.


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## Mop in Hand (Feb 5, 2009)

Nice drawings and explaination Willie T.


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## roc1479 (Apr 8, 2010)

Nice drawings Willie T.

Your diagram is a good illustration and pretty easy to follow. My existing step has 1 riser and a landing as you can see in the pic.

It's roughly 17" high, 70" wide and from the house to the tip of the landing it's 42". It's falling apart and I really would like to build a step like the one in your example using fieldstone.

I'm a bit confused about the width of the threads. Don't you think 1'5" is too wide? I'll measure mine to see what they are.

Do you think this diagram could be adjusted to support limestone treads similar to a brickface type step? If not, would I be able to find flags that are large enough for my landing?

Do I need to start out with a strip footing under the block as a foundation?

Thanks,

Rocky


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## Willie T (Jan 29, 2009)

roc1479 said:


> Nice drawings Willie T.
> 
> Your diagram is a good illustration and pretty easy to follow. My existing step has 1 riser and a landing as you can see in the pic.
> 
> ...


Answers in red.


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## jaceone (Aug 4, 2011)

a bit late to the party but i had a quick question regarding this:

i'll be weather permitting starting a project very similar to this this weekend and i wondered why the choice of going with those "precast lintel beams" rather than another course of cinder block? 

i removed and am fully rebuilding crumbling front set of steps that had cinder blocks as the skirt and rubble/sand as a filler.. non-rebar'd top slabs lead to 3 huge cracks and a toppled first step..

my version will also have 2 steps, 1 intermediate and a landing


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## Willie T (Jan 29, 2009)

The lintel beams just make it easier to span the width of the steps without having to lay any more blocks or pour any extra foundation concrete. It also gives your dog a lot more clear, unobstructed room under there to hang out.


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