Casting a flat surface on a stone pillar, is it possible?

[Grillen]

I have a stone bench that stands on two old stone pillars where the top is conical and I need to make it smooth. One option is to cut it, but I would need the height as it is or even a bit higher, so I'm considering if it's possible to cast concrete on top of it or if it won't hold up.

I was thinking about just building a simple frame around and drilling some smaller reinforcing mesh into the stone to get something to attach to.

Is it just a waste of time or could it work, do you think?

 

[Testarn]

It works.

 

[Nicro]

Why not screw a post shoe into the rock and secure it with anchor compound in the concrete pillar?

 

[Grillen]

Follow-up question.

I will be there over the weekend and have time to cast then, but I won't be able to bring a rotary hammer to make the holes, so I'm wondering if it will hold to just cast a flat surface directly onto the stone or if it won't adhere well without having drilled reinforcement bars into the stone pillar?

I'm thinking of laying one or two reinforcement rods where it slopes to get some reinforcement in the concrete but not anchored into the stone pillar due to the lack of drilling. Or is it doomed to fail?

Viewed from above, the somewhat pointed/conical stone pillar, I had planned to lay two rows of reinforcement as I have drawn with red lines on the image below.

 

[jonaserik]

It won't work by just casting against the stone. Concrete does not bond to rock, it just lies loosely. As you said, it involves reinforcing and drilling a lot of holes 5.5 mm with perhaps 5 cm apart. And plugging with stainless screws. Well, rebar under the screw heads is a must for the concrete to stay in place. Also, the top of the post should be primed at least twice and allowed to dry in between; it's good to mix fine sand into the primer so that the surface becomes rough for the concrete to have something to adhere/grip to.

 

[Grillen]

It won't work by just casting against the stone. Concrete does not adhere to rock, only lies loosely. As you say, it will require reinforcing, as well as drilling a lot of holes 5.5 mm with maybe 5 cm apart. And plug in with stainless screws. Of course, rebar under the screw heads is a must for the concrete to stay in place. Also, the top of the post should be primed at least 2 times and dry in between, it's good to mix fine sand into the primer, so the surface becomes rough so that the concrete has something to adhere to/bite into.

Thanks for the detailed response. Then it will have to wait until next time.