Underfloor heating on insulated intermediate joist

[honkytonk]

Hi!

Two-story house built in '63 where the intermediate floor consists of a concrete slab about 10 cm and on top of that it is studded with fiberglass insulation. On top of the studs is tongue and groove wood on which the floor lies.
I am now renovating the kitchen, hall, and bathroom and plan to install waterborne heating in all spaces. I will probably need to replace the existing insulation as it is worn out and filled with a lot of other debris.
The initial idea was to remove the tongue-and-groove and replace it with grooved particleboard for the pipes and lay tiles in all areas. Of course, all according to the manufacturer's instructions with heating plates etc. However, I think it seems quite complicated as it needs to be laid with a board over in dry areas and reinforcement and levelling in the bathroom. Additionally, the existing studding will probably need to be replaced as the old one is likely to warp after demolition and the new one should be laid with c/c 300.
Therefore, I am considering alternative solutions, such as polystyrene first and EPS casting on top of that where the pipe is cast directly in.
What are your thoughts on this? Other alternative solutions? What is the smoothest and easiest?
Soundproofing is important as we rent out parts of the downstairs.
Thanks in advance

 

[sturnus]

Styrofoam plus screed, yes, BUT NOT EPS! Why do you need a screed that's a heat insulator for your underfloor heating? Just a regular self-leveling screed for heated floors.

 

[honkytonk]

Styrofoam plus screed, yes, BUT NOT EPS! Why do you need a screed that's a heat insulator for your underfloor heating? Just a regular self-leveling screed for heated floors.

Thanks for the response.
The idea with EPS was to reduce the total weight. The pipe must be covered with 4-5cm of concrete if laid this way, and it requires so much self-leveling compound then.

 

[sturnus]

I overlooked that this is water heating. But then maybe it's better to use EPS or XPS boards with grooves for the pipes, then add 4 cm of concrete and 1 cm of self-leveling screed?

 

[honkytonk]

I overlooked that this is water heating. But then maybe it's better to use EPS or XPS boards with grooves for the pipes, then add 4 cm of concrete and 1 cm of self-leveling screed?

It’s a good thought but I forgot to mention that the framing is about 130mm so that’s the height I need to reach.

 

[sturnus]

so that is the height I have to reach.

Additional fragolit underneath? A smaller layer above the pipe promotes heat migration. Personally, I recommend underfloor heating only with clinker as the finish. All wood-like materials are also good heat insulators. Of course, all parquet manufacturers recommend them for heated floors, but none of them provide data on the thermal efficiency of such a solution.

 

[honkytonk]

Additional fragolit underneath? A smaller layer above the pipe promotes heat migration. Personally, I recommend underfloor heating only with clinker as the finish. All wood-like materials are also good heat insulators. Of course, all parquet manufacturers recommend them for heated floors, but none of them provide data on the thermal efficiency of such a solution.

Maybe it would work! 😁👍
I agree regarding clinker and that's exactly what I was planning to lay.
Do you mean by “a smaller layer above the pipe…” to pour with self-leveling compound on top of the pipe and then clinker on that?

 

[sturnus]

Eftersom detta är ett vattenbaserat värmesystem, behöver det finnas ett ganska tjockt lager ovanför röret. Personally, I'd use 3-4 cm thick Fine Concrete with 2 mm reinforcement. Then, I'd apply 1 cm of Flytspackel to even out the level and tiles.