ᐅ Older Building: Adding Underfloor Heating on the Upper Floor?

Hello everyone,

We are renovating a house built in 1986 and plan to install a new air-source heat pump. There is already underfloor heating on the ground floor, which will be connected to the new heating system. On the upper floor, there are currently panel radiators; however, for efficiency reasons, we were advised to retrofit underfloor heating upstairs, which we would like to proceed with.

Is there anything special we need to consider? Would it be advisable to hire a structural engineer for an assessment? The ceiling is made of concrete, with an insulation layer (?) on top, followed by a wooden covering. PVC flooring was then installed over that.

Are there any structural risks involved in adding underfloor heating on the upper floor?

Do you have bedrooms upstairs? Wouldn't it be easier to switch to suitable radiators? We are converting to underfloor heating on the ground floor, but I wouldn’t really want it in the bedrooms, and generally, suitable radiators are sufficient.

I agree with @Winniefred on this.
In our case, only the ground floor is being converted to underfloor heating (since we have to insulate below anyway), while the upper floors / attic will have suitable radiators installed.

Just consider the cost-benefit aspect.

Winniefred schrieb:

Do you have bedrooms upstairs? Wouldn't it be easier to switch to suitable radiators?

Thank you for your reply. Upstairs are children’s rooms and offices; our bedroom is on the ground floor. We had two different heating companies assess the situation, and both recommended installing underfloor heating on the upper floor. The existing radiators are far too small for a heat pump and would need to be at least twice as large. Since we have many sloped ceilings upstairs, this would mean losing a lot of valuable wall space. Additionally, the heating system would be less efficient because the flow temperature would have to be increased to get the radiators warm. At least, that’s what we were told.

There are special low-temperature radiators available for this purpose.
Otherwise, the old screed is usually milled off. It seems you don’t have screed on the upper floor, is that correct? I find it hard to imagine the structure you described without it.
For a house built in 1986, there shouldn’t be any issues; the contractors likely would have mentioned it otherwise. In our case, new screed is applied over a vaulted cellar from 1921, which also poses no problem. If you want to be absolutely sure, consult a structural engineer; it’s not very expensive.

Winniefred schrieb:

So, you don’t have a screed layer on the upper floor, is that correct?

If you want to be absolutely sure, consult a structural engineer—it doesn’t cost that much.

That’s right, on the upper floor we only have the concrete slab, then impact sound insulation, and on top of that a wood subfloor. The final floor covering is installed on this. At least, that’s how it was explained to us; we haven’t opened or removed the floor yet.

Thanks anyway for your reply. We might ask a structural engineer just to be safe. What kind of costs could we expect for that?