Underfloor heating in an old house?

[GrendelsMum]

I'm planning a couple of new bathrooms in our old (listed) house, and it suddenly occurred to me to wonder about underfloor heating.

I don't know how underfloor heating works in the least - does it involve raising the eventual floor level or digging around under the existing floor? Is it horrendously complicated?

It sounds as though it doesn't work at all with timber floors, which woudl probably rule it out, but I wanted to check before going for more radiators.

We are about to install underfloor heating in our 1930 house - half of it is going over timber, half over concrete (due to an extension). You just have to get the right type. Ours is Polypipe Overlay. Bear in mind you may have a small step up from other floors (it is about 18mm thick).

Oh, thank you very much - that's extremely thought provoking.

there are 2 types - wet and dry. wet is with pipes under the floor, full of warm water - bit like a radiator - and is linked to your central heating system Dry is electric, like a mat of electric wires under floor, that heats up, usually on a timer. we have both - electric in bathrooms, upstairs, small floor area. Wet in kitchen, bigger room, had major building work done including new floor, so it could be laid onto concrete before tiles go down.

For an old house which wont be up to insualtion standards of modern builds it has to be hot water. Also considering the temp drop in the winter electric is very expensive and having worked for a top M&E engineering company I was told to avoid electric at all costs. Good if there is another rad in the room but as you said its listed (like mine) the walls are thick, the ground slab didnt exist. room heights are also considered when working out the rooms cubic area.

We did ours without any permission and dug up the old floor and put in new slab & insulation. They fitted the pipes and then poured the cement mix over the top. This is considerable work, you must of all make sure the boiler is compatable. There are lots of pipes and what is called a manifold which is the box where all the pipes meet up.

With the 1st floor they used metal trays in between the joists and then timber sheets over the top which does add a few mm to the step up. Insulation needs to be placed between the ceiling joists.

The pipes need to be buried either into the wall, a cavity or boxed out.

Its a lot of work just for a small room and would be costly. Its best fitted as a whole.

Hope this helps.

Ah, thanks very much.

As you say, bugger all insulation in the house atm, but we hope to rectify that in time.

Something to mull over...

i believe that the best floor for UFH is concrete. you can do under floorboards but hte cost v benefit is not great or so I have heard from DH's mate who is a boiler technician & plumber. you could consider insulating under the floorboards this may be cheaper and just as effective apparently.