Casting an extension on an existing concrete slab

[Csyk]

Hello forum, I am renovating a shed on the property, which is located on a cast concrete slab. I would like to raise the floor about 50mm and have it insulated, with the final finish as a smooth durable surface, so I am thinking of using epoxy paint.

I am considering a few different methods:

1. Floating addition with embedded foam plastic. Plastic wrap the underlying slab, lay foam plastic, reinforcement, and cast with fine concrete on the reinforcement mesh. Finish with self-leveling compound and painting.

Advantages: -Simple and cheap
Disadvantages: -Risk of cracking in the overlay as the concrete layer becomes too thin.

2. Self-leveling compound with foam plastic.
Advantages: -Simple, durable
Disadvantages: -Expensive

3. Cast fixed addition to the existing slab and cast with insulating concrete.
Drill several holes for bonding and attach vertical reinforcement bars with anchor compound, tie these to reinforcement mesh, and finally cast with insulating concrete. Finish: self-leveling compound and painting.

Advantages: -Durable, cost-effective
Disadvantages: -Complicated and more expensive concrete

Does anyone have experience with similar projects or any other thoughts, tips?

Thanks in advance!

 

[nimhed]

I responded in the other thread in the incomplete post.

One detail you have omitted is the purpose of the renovation.

Is the shed to remain a shed (tool shed)? If so, I don't understand the need for floor insulation.

Is it being converted into a guest cabin? In that case, perhaps it shouldn't be poured at all, but instead, lay foam insulation and a floating floor on top.

Heated garage? Here too, I would question a few scant cm of foam insulation in the floor and instead, just pour a layer.

So, the purpose probably needs to be clarified.

 

[Csyk]

I responded in the other thread in the incomplete post.

One piece of information you left out is the purpose of the renovation.

Is the shed going to remain a shed (tool shed)? In that case, I don't understand the need to install insulation in the floor.

Is it going to be converted to a guesthouse? Then maybe it shouldn't be cast at all, but rather put polystyrene and a floating floor on it.

Heated garage? Here too, I would question just a few centimeters of polystyrene in the floor, rather than simply casting a layer.

So, the purpose probably needs clarification

Yes, it was a bit odd with post 1.
The purpose of the shed is to be used year-round as a combination of a workshop and possibly an office. The walls and roof are insulated, and there is heating. Previously, there was a floating floor consisting of polystyrene and chipboard directly on the concrete slab.

 

[nimhed]

There are surely those who know more about this than I do, but I wouldn't worry about the little insulation you might achieve with your new 50mm layer; I would simply cast with regular concrete.

I believe the insulation gain you achieve with your examples is highly negligible.