Concrete question

[Dadillac]

Not garage related. So I built a ground level deck last year. It is about 12.5 inches above the ground. I need one step to make it a bit more manageable. What I would like to do is pour a slightly wider than 4 foot and slightly deeper than a foot slab. After that dries I want to form a slightly smaller than 4 foot and slightly smaller than 12 inch deep step that is about 4 or 5 inches high. After that dries I want to mortar a 4 foot long limestone step pad on top of that. Question is will these 3 stages of construction bond to each other doing it like this? I will be also having a few rebars sunk into the ground sticking straight up so that steps one and two will be connected by rebar. Thanks

Don

 

[alexb2000]

IMO a good concrete contractor can pour that in one pour and avoid any cold joint issues. Also, people do it, but I don't like rebar sticking in the ground. The step pad should be no problem on top of concrete, just use a bonding agent.

 

[6768rogues]

You will have a "cold" joint between the pours, so they will not bond to each other well. You can dowel them together with some short pieces of rebar, but I prefer to use a board to create a keyway in the top of the lower concrete so the subsequent upper concrete keys to it. Work a board into the top of the concrete, then remove it when the concrete dries. It will make a slot or keyway. The mortar sticking the stone to the higher slab will adhere adequately. I would heavily broom finish it to give the mortar a better bite, don't hard trowel it smooth.
Also, when you form it I recommend putting the board that you use for the riser form at an angle so the top of it sticks out about an inch more than the bottom. That will give your steps a nosing, making them easier to walk on and making it look professional. Or you can let the stone slab overhang by an inch.
I would not put rebar into the ground, it will rust and that rust will travel up the steel and might crack your bottom slab. Rebar should always have at least an inch of concrete cover and preferably two inches.
If you want to keep it in place, dig a keyway into the ground. Then cast your bottom slab over the keyway, so that it will have to either displace soil or rise up to move. It will stay in place.
I agree that the concrete can be done in one step, but it is ok to do it yourself in two steps.

 

[Dadillac]

Well I am not a concrete contractor. I am a DIYer. My use of concrete has been limited in my lifetime. I know just enough to be dangerous. I only need one step. I was thinking of just making a single pour but thought that it will be higher than it is deep. That in my opinion will cause rocking after a few years. That is why I thought about having a larger base slab to stop that from happening. I was thinking if I use rebar from one pour to the next it should make a secure bond if the actual concrete pours do not bond. I guess that I could make a single form that would have the bottom slab and the step all at once. I just thought it would be easier for this concrete newbie to do it in separate stages

Don

 

[Dadillac]

So what I have done is poured a 12 x 48 inch pad between 4 and 7 inches deep. I didn't bother filling in the center of the hole to level it out. But the ends are at 4 inches. I then bought decorative cement blocks from Lowes to make a 4 inch base for the step. I laid them down using landscape adhesive. I am waiting a few hours for the adhesive to get a good set and then I will be mixing up some Portland and installing the stair tread on top. Should end up fine.

Don