Topic 'Re: Grading Concrete' in forum 'Home Improvement' - dslreports.com

Re: Grading Concrete

Mon, 29 Sep 2014 00:14:53 EDT

PrntRhd posted : I would keep the step separated vertically so the slab can move a little without cracking. You could make a thin form around the step area and pour concrete on top of the cleaned step area to even out the height if that is your desire.
I looked up how long a ready mix concrete truck can hold a load:
Best if used within 60 minutes after adding water, meaning you have to get the truck unloaded and in position in an hour. So you will need enough additional helpers so you can get all the concrete to fill your forms in that length of time. I don't know anyone who is strong enough to unload a truck themselves in an hour.

Re: Grading Concrete

Sun, 28 Sep 2014 19:44:10 EDT

joewho posted : Deck will raise height. Deck will leave room for critters under it. Deck will have more code compliance. etc.,etc.

Re: Grading Concrete

Sun, 28 Sep 2014 18:45:12 EDT

robbin posted : Why not just deck over it -- looks like there is room height wise.

Re: Grading Concrete

Sun, 28 Sep 2014 18:36:22 EDT

joewho posted : Not so sure I want it attached to the house. From here, looks like a pita to do anything with. Probably more work with the stoop than the whole slab. If it has a footer, anything I do will have to be on that footer, including new slab. Rise and fall of the ground around that footer will cause a square shaped crack the size of this stoop. I'd like to cut it down, but wouldn't the footer, up to the new dimension, have to be cut below grade? Or would I need to put something in between the left over footer and the slab?
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Re: Grading Concrete

Sun, 28 Sep 2014 16:17:15 EDT

PrntRhd posted : The stoop likely has a footer of 30 inches or so, but not to bedrock.
It could be broken up and replaced or could be cut smaller with concrete saws, leaving the height intact.

Re: Grading Concrete

Sun, 28 Sep 2014 15:47:56 EDT

joewho posted : Heh, it's tied to the house alright. That monster sits, while the garage foundation cracks. It's just too big for what we can use. Want it out and a stair, if necessary, height wise. Now I'm wondering if the stoop has a footing down to bedrock and I'll have to bed the whole substrate like the damned stoop? J/K.

Re: Grading Concrete

Sun, 28 Sep 2014 15:33:48 EDT

PrntRhd posted :

said by joewho:

I get that the step, or anywhere along the structure needs to be stable. Here's a pic of the current stoop. Is that solid concrete or is there a frame? Taking it out is a worry. Disposal is a worry. At any rate, looking at the stoop, can you assess stability?

Current stoop can be left and poured around if necessary, I had that done when we poured our patio out here in California. We get some ground swelling and shrinkage in the clay soils here but your frost heaving causes much more movement.
I would guess the stoop is tied to the house foundation and properly engineered if it sits to the house properly today.

Re: Grading Concrete

Sun, 28 Sep 2014 15:29:52 EDT

joewho posted : I get that the step, or anywhere along the structure needs to be stable. Here's a pic of the current stoop. Is that solid concrete or is there a frame? Taking it out is a worry. Disposal is a worry. At any rate, looking at the stoop, can you assess stability?
Just to validate, your input saves me hundreds of dollars.
I know you have to put something between the house and the slab, if that's what you're trying to tell me.

Re: Grading Concrete

Sun, 28 Sep 2014 15:19:42 EDT

PrntRhd posted :

said by kherr:

Around here it's $500 to just show up with a pumper ....

There is a reason why they can charge that price...it is worth the money.
Concrete is really heavy stuff.
The ready mix truck can only keep the concrete in the truck for a finite time as the material keeps changing as it mixes. You cannot keep the truck there all day.
There are batch concrete trucks but they usually charge even more per yard than the larger ones.

Re: Grading Concrete

Sun, 28 Sep 2014 15:18:21 EDT

kherr posted : Around here it's $500 to just show up with a pumper ....

Re: Grading Concrete

Sun, 28 Sep 2014 15:15:46 EDT

PrntRhd posted : The slab can float in most cases if the subgrade is drained large gravel and is substantial enough. You want a 4 inch slab in most cases. The main concern is cracking/tilting near the house and keeping runoff away from the house foundation.
Ready mix is the stuff I was talking about, it is more consistent for slab appearance and is easier than shoveling gravel, sand, and portland cement into a mixer and then wheel barrow moving the concrete into the forms.

Re: Grading Concrete

Sun, 28 Sep 2014 15:15:15 EDT

joewho posted : Ha, Pissed at the bears right now. Had a mixer driver friend over a couple weeks ago. I forget how much he said the truck weighs, but trees and distance to the street make it difficult. Was looking for the leftovers of a big pour, but no luck. Are you talking about a Co. named redi mix? Red trucks?

Re: Grading Concrete

Sun, 28 Sep 2014 15:05:56 EDT

PrntRhd posted : After all my years of manual digging, the creation of rental Bobcat loaders with a small backhoe attached makes that type of dirt excavation much less likely to cause long term injuries.
You also want to plan on where you are going to dispose of all the dirt/gravel being removed since moving it once is better than twice.
Also, it makes it much quicker and less painful if you get the redi mix concrete guys to bring a small concrete pump to get the material from the truck into the forms for the pour.
You can rent a mixer and do it all by hand but the time and physical labor is much more.

Re: Grading Concrete

Sun, 28 Sep 2014 14:56:02 EDT

joewho posted : Reading and learning at the same time, one more edit. Am thinking that a floating wood step would help with heaving. But can I add structural footings while doing the slab?

Re: Grading Concrete

Sun, 28 Sep 2014 14:47:58 EDT

PrntRhd posted : You want to have mesh steel reinforcing steel in the slab concrete pour and you want to have a deep footer and rebar in the step itself. As previously described, you make the forms with some grade so when the slab is poured it will get the water to run away from the house.
The ground heaving due to frost in the winter will cause the step to move and tilt if you don't engineer it correctly and you will have to break it up and do it again. (I lived in IN to your east)

Re: Grading Concrete

Sun, 28 Sep 2014 14:04:16 EDT

joewho posted : Saying maybe rebar would help me avoid 5" of gravel. Pretty sure this ground is so hard packed already that I could get away with it. But, does anyone know if sand would work? Thinking stability and drainage. We have pretty good natural drainage/runoff just because we live close to a river, think downhill. Would the patio slide around on the sand?

Re: Grading Concrete

Sun, 28 Sep 2014 13:58:06 EDT

joewho posted : I'll use the reinforced, for sure. Using 10% tensile of compressive, still won't be much shear or torsion for our use. I'd think that rebar would be insurance against any changes in the substrate. I surely don't want to pour and pound compressible aggregate. When younger, I was labor in a union gravel pit. Hurts my back thinking about the shovel. Pretty sure this substrate is very hard packed, won't know until I take the rock out. So far, my wife and neighbors kids have been taking it out a little at a time. Thanks for your input. Your thoughts?
Edit: Looking around the garage that I just re-organized, we don't have any square shovels or a wheelbarrow. I'm not saying that to my wife until I'm ready to do the whole shebang. Sounds lazy, but I am in direct contact with women who "know more than I do" all f,kin day.
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Re: Grading Concrete

Sun, 28 Sep 2014 13:36:55 EDT

robbin posted : Steel adds tensile strength. By itself, concrete has compressive strength but very little tensile strength.

Re: Grading Concrete

Sun, 28 Sep 2014 13:21:18 EDT

joewho posted : I'm a painter by trade, liquid management. Concrete is much thicker. Got it. Was thinking that since it's 10x18, rebar may not be necessary, with the correct concrete. No? Being a small project, re-bar wouldn't cost that much. Also, it's flat and stable ground. Thought of rebar for thicker or hilly pours. I have worked the dumb end of a shovel on a couple of concrete pours.

Re: Grading Concrete

Sun, 28 Sep 2014 13:14:27 EDT

robbin posted :

said by joewho:

If liquid levels itself, how do you create a grade for runoff with concrete, for a patio?

You probably should get someone to pour this for you. Working with concrete is nothing like working with a liquid. Think of it more like wet rocks and sand with a little syrup mixed in. It is hard and heavy to work with.

Notice you said you don't want to use rebar. Why? Although not necessary, I would use rebar at least at the edges with remesh in the rest. Being cheap with steel is false economy when poring concrete.

Re: Grading Concrete

Sun, 28 Sep 2014 13:12:07 EDT

joewho posted : That would mean footings, stairs and rails. Not sure which would be cheaper.

Re: Grading Concrete

Sun, 28 Sep 2014 13:01:23 EDT

Cho Baka posted : I'd probably go for some sort of interlock or a wood deck.
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Re: Grading Concrete

Sun, 28 Sep 2014 12:29:59 EDT

joewho posted : More input cho. How would you do it? Here are a couple pictures of what I'm working with. 10' x 18'. Hard dirt under various sized rock. Some rock already removed. Our house is situated close to the property lines on the back, on a corner lot. So what you see is pretty much our back yard. I want to take out the huge stoop, pour concrete and install a step. Ideas and input welcome. The fence means nothing, it was here when we bought and I only leave it there to keep the rock in.
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I see what you mean cho. I want one big slab. Hoping not to use rebar.

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Re: Grading Concrete

Sun, 28 Sep 2014 12:13:20 EDT

DataDoc posted : The patio is being cast in 4 slabs instead of one large slab.

Re: Grading Concrete

Sun, 28 Sep 2014 12:12:19 EDT

Cho Baka posted : To make it easier for amateurs perhaps?

I am not a fan of doing it that way.
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Re: Grading Concrete

Sun, 28 Sep 2014 12:04:04 EDT

joewho posted : »www.quikrete.com/AtHome/ ··· ions.asp I was just going to post this link. It shows how to grade at 1/8 per foot. In one of the photos, there are 2x4s across the center. What is that for?

Re: Grading Concrete

Sun, 28 Sep 2014 11:41:46 EDT

DataDoc posted : You don't mix concrete so soupy that it flows like water. You make the forms have a slope and screed it level with them.
»www.quikrete.com/Patio/

Grading Concrete

Sun, 28 Sep 2014 11:25:08 EDT

joewho posted : If liquid levels itself, how do you create a grade for runoff with concrete, for a patio?