EPS, Level or tear out the base plate?

[LiteForce]

Hello!

We are planning to renovate the basement in a house from 1974. We have drained the house with ISO drän and now intend to restore the floors in the basement. There was previously a floating concrete floor on the underlying sand bed that has now been torn out, and what remains is the foundation slab, which is roughly cast and uneven. There is between 10-13 cm to the floor level.

As we understand it, there are three options.
1. Pour eps 7cm, reinforce, and install underfloor heating on eps, then level 3cm.
2. Same as above eps but without underfloor heating.
3. Level battens with air gap.
4. Remove the foundation slab, insulate 30 cm, reinforce, install underfloor heating, then pour concrete.

We are very unsure about the best method to use for our basement. What is really better, eps or level battens if the foundation slab remains?

Is it best to also remove the foundation slab to redo everything completely?
Is it cheaper to remove the foundation slab and restore with insulation, underfloor heating, pouring than the eps method?
What is the cost-effective, cheapest, and at the same time best solution?

There are so many skilled people here on the forum, we hope you can kindly help us with your opinions on this difficult subject.

 

[Demmpa]

I am building a raised floor, Subfloor, with 45mm insulation hanging on insulation carriers in one of the basement rooms. We are using their metal studs. https://subfloor.se/

 

[LiteForce]

I'm building a subfloor with 45mm insulation hanging on insulation carriers in one of the basement rooms.
We're using their metal studs.
[link]

Ok, it looks similar to the leveling system. Is it better to use studs rather than pouring in the basement? I'm so torn about which method is safest and the best to use in the basement. How did you come to the decision to use studs instead of pouring the floor? Would you have used studs if it were for the entire basement as well?

 

[witten]

Have you checked foamed concrete?

 

[Demmpa]

Partly we wanted warmer floors than the uninsulated slab we have today, and partly we're changing the floor plan a bit; this room will become a bedroom.
We removed about five cm thick painted concrete floor that was on top of the slab, walls, door frames, etc., are/were embedded in the concrete floor but everything is on the slab.

We will frame up another room, which will become a workspace.

Then in the basement storage room, we will lay tiles, we will tear up the concrete floor and then level it with self-leveling compound before laying the tiles.

The recreation room has Platon - styrofoam - parquet.

 

[LiteForce]

Have you looked at foam concrete?

Yes, we have looked into it, unfortunately, it seems that foam concrete does not have very good insulation properties. Regarding insulation properties and concrete, EPS seems unbeatable and insulates equivalent to 50% of comparable cell plastic. 10cm of EPS corresponds to 5cm of cell plastic, according to our information. This means that foam concrete is not suitable for underfloor heating.

 

[LiteForce]

Partly we wanted warmer floors than the uninsulated slab we have today, partly we are changing the floor plan a bit, this room will become a bedroom.
We chipped away about five cm thick painted concrete floor that was on top of the slab, walls, door frames etc. are/were embedded in the concrete floor but everything stands on the slab.

Will frame up another room, which will become an office.

Then in the basement storage, we will lay tiles, we will tear out the concrete floor then use self-leveling compound to lay the tiles.

The family room has Platon - styrofoam - parquet.

Shouldn't you frame up in the basement storage to be level with the other floors, then use self-leveling compound and lay the tiles?

 

[LiteForce]

We are getting closer to a solution for the basement now. It seems to be leaning towards Nivell, subfloor, or Granab ventilated floor, which appear to be the best options for an uninsulated foundation slab to avoid emissions and potential ground moisture. From what we understand, these systems are considered approved and not as a risk construction in basements.

The question we are now considering is Nivell vs. Granab vs. subfloor, which one to choose among these three. Nivell and Subfloor seem to be the same; Granab has its battens in steel, which seems better against potential moisture.

 

[Demmpa]

Shouldn't you frame up in the basement storage to level with the other floors, then pour leveling compound and lay the tiles.

No, we want parquet in the bedroom and in other living areas.

I broke away the top concrete layer (about 4-6 cm) down to the actual slab, the parquet floor will be about 6 cm above the old floor.

 

[Demmpa]

The question we are now considering is Nivell vs Granab vs subfloor, which one should you choose out of these three? Nivell and Subfloor seem to be the same, Granab has its joists in steel, which seems better against any moisture.

Subfloor also has steel joists, the same legs and insulation carriers for both steel & wood joists, it is the steel joists that we chose.

 

[lmoberg]

Does anyone have an idea of the approximate cost for a Nivell or subfloor of about 20sqm?

 

[Demmpa]

We paid approximately 10kkr for floor joists, legs, concrete nail plugs, insulation carriers, and insulation. Our space is about 17 square meters, but the material is delivered in fixed intervals, and the joists are sufficient for about another 10 square meters. The insulation was just enough with three packages, but we took four to be on the safe side.

When we continue with the next space, I will try to optimize the placement of the joists before ordering.