Underfloor heating on a half concrete, half wood floor

[johnologi]

Hello

The previous owner of our house has built an "entrance hall" over the existing external concrete steps. This entrance hall is insulated and the walls are finished, but I am planning to fix the floor now and have some questions.

I made a very simple sketch that might help to understand...

The hall is 2m2 and currently half of the floor is concrete (the existing old outer steps, black) and the other half I plan to build up with insulation and floor panels (blue piece).
Under the old concrete steps, there is an outdoor storage room, so the steps are quite cold.

• What should I insulate the green area with, under the floor I am building up?
• Am I thinking correctly if I frame up and put down a floor panel to get the same level (blue)?

On top of this, I want to install electric underfloor heating and tiles.

• Should one lay a panel over the concrete/floor panel before installing the underfloor heating to get a unified floor, if so, what type of panel?
• I was thinking self-leveling compound T2-blue or T2-quicknet?
• Read that there was a panel called ISOLECTA...

Many questions and I am grateful for any tips to avoid issues in the future... And yes, I will contact an electrician for the heating

Thank you in advance

John

 

[WaldenWoods]

I don't know how high above ground this is or what moisture conditions prevail, but generally when you convert spaces that have been outdoors/uninsulated to indoor/insulated, there's a risk of moisture migration followed by mold problems if not done correctly. If there is any risk that your concrete stairs contain moisture at any time of the year, I would be careful not to place wooden beams or any other organic material directly against them. Either metal studs (like Granab) or wooden studs on a metal spacer (like Nivell, but since this situation looks quite special, it's probably best for you to come up with your own solution). And for the same reason, if your floorboard is made of wood, which I assume it is, place plastic in between where it meets the concrete stairs.

 

[johnologi]

Thank you for the answer, yes it is indeed a slightly different material. I have checked with T2 and their Isolecta can be used on concrete (allows any moisture to pass through). I will place a moisture barrier between the wood and the concrete.