Casting over holes in the floor.

[steffe79]

I have some ventilation ducts that go up from the basement through the house to the attic and the chimney. I am going to remove them now in connection with the renovation and arrange the ventilation in another way. The floor consists entirely of concrete (2 dm) down to the basement and the plan is to seal the holes. I was thinking of using a primer and then coarse concrete with a chipboard pressed against the ceiling in the basement during curing, possibly some release agent. Possibly seal the board at the edges. Is there anything else I should think about? I haven’t done much casting before so I feel a bit uncertain.

 

[steffe79]

It can be added that I hadn't planned to lay any flooring there, however, a pantry cabinet will be placed over the holes.

 

[Stefan N]

Dub in a pair of irons on the side so it's calm.

 

[Thyselius]

How did the result turn out for TS?

I'm working on a similar project. I removed two ventilation pipes and a "shield?" for the chimney pipe from the boiler (neither the boiler nor the chimney pipe is left).

What should be used to achieve very good strength in the casting (apart from "dubbing," which might be tricky in my situation because I've already found 5 cable pipes cast between the holes for the ventilation pipes) and at the same time quick curing? Perhaps it's difficult to achieve both.

The thickness of the concrete slab is about 150mm.

 

[steffe79]

How did the result turn out for TS?

I'm working on a similar project. Removed two ventilation pipes and a "shield?" for the smoke pipe from the furnace (neither the furnace nor the smoke pipe are left.)

What should be used to achieve excellent strength in the casting (besides "dubbing," which can be tricky in my situation as I've already found 5 cable conduits embedded between the holes for the ventilation pipes) and at the same time fast curing? It might be hard to get both.

The thickness of the concrete slab is about 150mm.

I almost think I used EPS/Cellbetong. It turned out perfect and was easy to work with. However, the house has been sold for some time now so I can't show any pictures - all the renovations eventually ended in separation

 

[Thyselius]

I almost think I used EPS/Cellbetong. It turned out perfect and was easy to work with. However, I've sold the house some time ago, so I can't show any pictures - all the renovations ended with separation in the end

I used Finbetong and cast in two stages, and reinforced with rebar. Need to figure out a solution regarding ventilation as it's pretty poor. It got worse when the boiler was removed.

Sorry to hear that, hope things are better now.