please review electric floor heating plan

[Petar]

I have a light cement floor that I intend to install electric floor heating and then tiles on top of.

I would like the installation to be as thin as possible and I would appreciate it if anyone can review the plan and offer any feedback.

Insulation:

https://ybsinsulation.com/brands/floorquilt/ 

The insulation manufacturer has told me that I can install the insulation without any glue or I can use a non-solvent based product. They also told me that there should (ideally) be some kind of barrier between the insulation and floor heating and that insulation gets damaged at 80°C (floor heating manufacturer told me that floor heating runs at 70°C).

 

Electric Floor Heating:

https://shop.fenixgroup.cz/z1587-topna-rohoz-ldts-160-0-5 

 

My floor heating installer had used a very thin layer (~2mm) of liquid levelling/thermal mass product on top of electric floor heating on some other floors. I still need to find out the name of this product. 

Tiles

The tile installer wants to use levelling cement + tile grout and I would also like to review this part of the process to make sure that it results in the thinnest installation possible.

[ProDave]

If that is ALL the insulation you are fitting on a (assumed) un insulated floor, then the electric UFH will be very ineffective and very expensive to heat as a huge proportion of the electricity used will just be heating the under floor space.  Most people consider a minimum of 100mm thick PIR type insulation to be required.

 

And in any event electric UFH is probably the most expensive way to heat a room, and no means to repair a fault in the heating mat if one occurs.

[Petar]

4 minutes ago, ProDave said:

If that is ALL the insulation you are fitting on a (assumed) un insulated floor, then the electric UFH will be very ineffective and very expensive to heat as a huge proportion of the electricity used will just be heating the under floor space.  Most people consider a minimum of 100mm thick PIR type insulation to be required.

 

And in any event electric UFH is probably the most expensive way to heat a room, and no means to repair a fault in the heating mat if one occurs.

Yeah, you're right. Ideally, there would be the ability to put thicker insulation underneath. I purchased the insulation that I purchased because I thought that it would be better than nothing, at least. 

Also, that's a good point about no way to fix a fault, but I've already purchased the floor heating and since the electrical installations exist then I guess I should probably just go ahead and use it.

At this point, I just wanna make sure of things such as:

1) floor heating won't damage insulation if installed directly on top of it
2) liquid leveling/thermal mass can be super thin
3) tiles can be installed on top in thinnest/most effective manner possible

[Benpointer]

We fitted electric underfloor heating to a large garden room we built on the back of our then house 20 years ago.  

 

It was really lovely...  Until the first electricity bill came in, at which point we realised it was costing us >£200pm to run.  We switched it off and resigned ourselves to not using the garden room in the winter.

 

Of course insulation was a topic unknown to us in those days.

[SteamyTea]

59 minutes ago, Petar said:

floor heating won't damage insulation if installed directly on top of it

I am pretty sure it will damage it.

Plastic deformation does not happen at a set temperature, it gradually gets greater, the higher the temperature, add in a local hotspot, and it can fail quite quickly.

 

Rethink your plans, a wall mounted panel heater will be cheaper and more reliable.

Maybe a cheap A2AHP.

 

 

Just looked at that insulation, it better be cheap as it is only packaging material.

 

Edited October 4 by SteamyTea

[JohnMo]

Couple of observations 

Foil insulation works with an air gap either side, so it acts as a reflective membrane. The insulation value other than that is pretty rubbish.

 

Would rethink your way of heating.

[ectoplasmosis]

1 hour ago, Petar said:

I have a light cement floor that I intend to install electric floor heating and then tiles on top of.
 

 

That insulation product won't be doing much of anything I'm afraid. With your current plan, it will be very expensive to heat the room.

 

What is the current ceiling height? Could you add 100mm PIR insulation underneath the electric mat? If not, then as mentioned above, an air-to-air split heat pump system will be much more effective and cheaper to run.

[Mr Punter]

Unless this is for occasional use in a small room like a bathroom it will be prohibitively expensive to run.

[Alan Ambrose]

OK here's my 10c. I've installed a three of these and I've had a couple installed elsewhere (not by me).

 

The comments above are kind of true. You don't mention what is below the 'light cement floor' or what room this is. Bathroom? It makes it so much harder if we have to extract the clues from you like some kind of cryptic crossword.

 

My floors were all in flats so it wasn't like there was 300mm of concrete below. 4 bathrooms, one kitchen. I think these were laid on the subfloor in all cases (probably chipboard) with a thinnish (maybe 6mm) 'tile backer' board. I would have used a thicker board knowing what I know now about insulation. The three I laid were all heating wire rather than heating mat. Two had ceramic tiles over (I didn't lay those two), one plastic tiles of some sort, two resin (Suba I think). You might want to put in an extra thermistor btw for redundancy.

 

They all work(ed) fine (one flat is sold now). All on a thermostat and a timer. Not too expensive to run. Very quick to heat up. Quite effective I think. Lovely if you like warm feet in the bathroom.

 

One failed - due, I think, to something leaning against the controller causing it to overheat.

 

I have UFH in one bathroom now at a different property. Works fine again, much slower to heat up. Not sure what's below it.

[Petar]

1 hour ago, Alan Ambrose said:

OK here's my 10c. I've installed a three of these and I've had a couple installed elsewhere (not by me).

 

The comments above are kind of true. You don't mention what is below the 'light cement floor' or what room this is. Bathroom? It makes it so much harder if we have to extract the clues from you like some kind of cryptic crossword.

 

My floors were all in flats so it wasn't like there was 300mm of concrete below. 4 bathrooms, one kitchen. I think these were laid on the subfloor in all cases (probably chipboard) with a thinnish (maybe 6mm) 'tile backer' board. I would have used a thicker board knowing what I know now about insulation. The three I laid were all heating wire rather than heating mat. Two had ceramic tiles over (I didn't lay those two), one plastic tiles of some sort, two resin (Suba I think). You might want to put in an extra thermistor btw for redundancy.

 

They all work(ed) fine (one flat is sold now). All on a thermostat and a timer. Not too expensive to run. Very quick to heat up. Quite effective I think. Lovely if you like warm feet in the bathroom.

 

One failed - due, I think, to something leaning against the controller causing it to overheat.

 

I have UFH in one bathroom now at a different property. Works fine again, much slower to heat up. Not sure what's below it.

It's a ground floor.

Some parts of the floor have old tile that light cement was poured on, and others have heavier cement below light cement.

The floor consists of one large floor that will be kitchen and dining room, another smaller area that is a living room, another that is hallway to a bedroom and a bathroom. 

Please let me know if you need any other details.

Edited October 4 by Petar

[Alan Ambrose]

>>> It's a ground floor.

 

Ah, I wonder if you have any idea what’s underneath and whether there’s any insulation at all? You can guess based on the age of the building or core drill to get a better idea. For rooms that get intermittent use, you can heat only for the hours you need to use them, but that may be less possible for rooms that are more occupied. In the worst case (concrete all the way down) you might like to get as much xps/eps insulation in as reasonably possible.