Concrete thickness over existing slab

[Bob Noel]

My googlefu is failing me...

Any words of wisdom with respect to how thick a pour should be over an existing slab of concrete? (assume the existing concrete is properly prepared)

Situation: existing unheated sunroom in the northeast (built 10 years ago). Existing slab has apparently settled a bit. Under the tiles is some wood framing on top of a slab (not an ideal job). I might was to remove the wood framing and build up the subfloor with more concrete and/or cement board or... just remove entire floor and start again.

Thanks

 

[Clip4]

https://www.cement.org/docs/default...rfacing-concrete-floors.pdf?sfvrsn=4&sfvrsn=4

The minimum recommended thickness is 1 to 2 in. (25 to 50 mm) for a fully bonded concrete overlay placed on a base slab that is practically free of cracks and in which the concrete is sound, clean, and of good quality

 

[ColoPilot]

If the slab just settled some, can you have it mudjacked? It's a lot cheaper than new concrete so if settles again you're not out much for trying.

 

[Huckster79]

I had a front porch that settled to tip back to the house that I’d bought on foreclosure, it had rotted the bathroom floor because of it. I prepped it and used sand mix on top and I think think my thin edge was thin like 1/2”. I confirmed the quick Crete bag says 1/2” to 2”.

it worked well and the thin edge never split and water once again rolled off and away from the house. There’s a bonding agent ya put between the two... I just built new forms to get my desired slope- so it was like 2” at the back and 1/2” at the front. Mix it stiffer than thinner to be tougher when done too.