Insulate basement wall internally.

[holetaker]

We are going to prepare a room in the basement, where an exterior wall is partially underground and is drained, and an exterior wall that is excavated. We have installed a door in the excavated wall.
Now the exterior walls need to be insulated on the inside, and I see two ways to do this.
Either I glue on siporex blocks and plaster them, or I build a ventilated inner wall with steel studs, rock wool, and drywall.
Which is better?
The floor will have tiles and no underfloor heating.

 

[justusandersson]

Without knowing the material of the outer wall, I would still prefer the solution with glued lightweight concrete. It is a more trouble-free construction.

 

[Jonatan79]

Otherwise, glue EPS boards, apply mesh, and plaster.

 

[holetaker]

Without knowing the material of the outer wall, I would still prefer the solution with glued lightweight concrete. It is a more trouble-free construction.

Sorry, my bad. We have lecca block in the outer wall. 25 cm thick.

 

[holetaker]

Otherwise glue EPS boards, apply mesh and then plaster.

Ep

Otherwise glue EPS boards, apply mesh and then plaster.

Styrofoam I guess? Is it the best for interior insulation?

 

[Jonatan79]

Good insulation value and you can choose the thickness by, for example, laying several layers overlapping.

 

[justusandersson]

Siporex blocks with the lowest volume weight available have approximately half the insulation value compared to cell plastic. If you have plenty of space, you can get a better wall construction with twice as much siporex on the inside. Higher volume weight and not as fragile.