Underfloor Heating

[AF-Ext]

Thinking of doing a retrospective water heating system in a kitchen, but don’t want to increase the overall floor level, someone has mentioned a company that cuts channels into the top of an existing slab [hyperlink removed by moderator] has anyone had any experience with this type of installation, and any ideas of how efficient it is compared to an in-screed system.

[ProDave]

If you just put water pipes into en existing un insulated screed it will be pretty ineficcient with most of the heat going down into the ground.

[Jeremy Harris]

I'd have to agree with @ProDave, with no insulation under the screed/slab it will waste more heat than it delivers to the room.  As a guide. underfloor heating needs better underfloor insulation than normal heating, because the floor surface will be a fair bit warmer, so accelerating the rate of heat loss downwards to the ground or undercroft.

[Onoff]

Rather than gut my kitchen I did discuss on here a while back, the merit of just digging a bfo rectangular hole in the large, clear floor area, insulating the bottom of the hole and sides and putting UFH in. It's probably a goer idea wise. 

 

BUT...the existing kitchen ffl is nom +100mm than the rest of the ground floor. So it's back to gutting the kitchen and digging down. Not like I haven't done that before! 

 

 

[jack]

18 hours ago, Onoff said:

Rather than gut my kitchen I did discuss on here a while back, the merit of just digging a bfo rectangular hole in the large, clear floor area, insulating the bottom of the hole and sides and putting UFH in. It's probably a goer idea wise. 

 

BUT...the existing kitchen ffl is nom +100mm than the rest of the ground floor. So it's back to gutting the kitchen and digging down. Not like I haven't done that before! 

 

Under no circumstances should you wait until the bathroom is finished before starting this!