Experience with retrofitted underfloor heating in an old building

Hello,

I am currently renovating my condominium.

Briefly about the apartment
It was built in 1980
1st floor
Double glazing
I have already replaced the roller shutter box with a new modern one

Floor structure:
2.5cm polystyrene boards
Remaining screed up to a total of 10cm

My plan was now to install a new gas heating system and additionally mill in underfloor heating.

The heating engineer told me that the pipes are only milled 2cm into the screed.

My concern is that because the apartment is on the 1st floor, the heat will be lost?

Has anyone had experience with such underfloor heating?

Thank you very much!

Additionally: The current heating is located in the apartment. So the distributor would accordingly also be located there.

Has anyone had experience with such an underfloor heating system?

In the end, it’s a completely normal underfloor heating system. The disadvantage is the relatively high price (new screed is similarly expensive) and the less flexible installation distances. However, in terms of effect, it is identical to other systems. But: Please remember that you need the approval of the homeowners' association for this structural measure. Also, it may not be possible to simply connect the underfloor heating to the new gas heating system. A mixing valve might be necessary to reduce the high flow temperatures of the gas heating to a tolerable level. You just have to keep that in mind and consider it during planning. Oh, about heat loss downwards. Yes, you will have that. You have it – if the floors above and below are not heated as much as yours – possibly even with radiators. If you want to minimize heat loss downwards, grab some friends and a sledgehammer and break up the old screed on a Saturday with a crate of beer. Then have new (good) insulation installed under the screed and pour 6–7 cm of screed again.

Okay, that would also have been an option to renew the screed. But I think it’s out of the question due to the costs. Purely in terms of efficiency, the underfloor heating would be better, or am I wrong? Because then I would have had to replace the radiators, as they are already very old.

Okeey that would also have been a consideration to renew the screed. But I think it’s off the table because of the costs.

It shouldn’t differ much. Especially if you swing the hammer yourself.

Purely in terms of efficiency, underfloor heating would be better, or am I mistaken?

Yep, because lower supply temperatures are sufficient.

Because then I would have had to replace the radiators, as they are also very old

Another reason for underfloor heating. And you gain space on the walls.