Laying underfloor heating mats under tiles

justagirl

I am taking up old tiles and laying new ones. I am considering putting down those electric heating mats under the new tiles in a sunroom. Can these be easily laid directly onto concrete floors and tiler tile over them? I'm looking to buy one with a timer that I use only when its very cold as the sunroom does not retain heat very well (no way around that unfortunately). Has anyone done something similar? If so, any pointers as to where I should buy them (Leinster area) Thanks so much.

Dr_Colossus

Not familiar with the heat mats or their convenience in laying under tile but one system I came across when researching shower drains recently was Schluter Ditra Heat that may be of interest. Tiles.ie appear to stock the Schluter products as per below:
http://www.tiles.ie/schluter-ditra-heat
No idea how expensive it is to run non can I advise as to dealing with Tiles.ie as I've never been a customer but it may give you another avenue to look into.

justagirl

Dr_Colossus wrote: »

Not familiar with the heat mats or their convenience in laying under tile but one system I came across when researching shower drains recently was Schluter Ditra Heat that may be of interest. Tiles.ie appear to stock the Schluter products as per below:
http://www.tiles.ie/schluter-ditra-heat
No idea how expensive it is to run non can I advise as to dealing with Tiles.ie as I've never been a customer but it may give you another avenue to look into.

Thank you Dr_Colossus - that looks like a good option. I'm really looking for something that will work and that's easy to put down as I'll be doing it myself (apart from electrics).

Just wondering if anyone else on here has put something similar down themselves.

CelticRambler

My dad put one of the cable-in-a-mesh type mats in a bathroom during it's refurbishment. He's an accomplished DIYer so wasn't expecting to have (m)any difficulties, and he didn't, other than a bit of head-scratching over exactly how to reshape some bits to flow around the existing fittings. That'd be about ten years ago now, has worked without a problem since then. It's an upstairs bathroom, mind you, on a wooden floor, so not entirely the same situation as yours.

If you're already having problems with heat-loss, though, you'd want to think about your floor insulation. Having a concrete base to store the heat is ideal, but if it's not already insulated underneath, you might find you're losing more heat downwards than is making it to knee-height.

justagirl

CelticRambler wrote: »

My dad put one of the cable-in-a-mesh type mats in a bathroom during it's refurbishment. He's an accomplished DIYer so wasn't expecting to have (m)any difficulties, and he didn't, other than a bit of head-scratching over exactly how to reshape some bits to flow around the existing fittings. That'd be about ten years ago now, has worked without a problem since then. It's an upstairs bathroom, mind you, on a wooden floor, so not entirely the same situation as yours.

If you're already having problems with heat-loss, though, you'd want to think about your floor insulation. Having a concrete base to store the heat is ideal, but if it's not already insulated underneath, you might find you're losing more heat downwards than is making it to knee-height.

Thanks so much CelticRambler .... the floor in question is the cement foundation for a sunroom ... I've absolutely no idea what's underneath unfortunately as was here when I moved in (12 years ago)... I'm assuming no insulation? the walls are low and hollow block, roof is insulated really well so heat escaping through tiled floor, walls, and windows (am looking at shutters with insulation)... so I thought throw an underfloor heat mat under the tiles, there is one radiator but it's not sufficient when it's really cold.....

CelticRambler

An afterthought: when you said above buy one with a timer that I use only when its very cold did you mean thermostat?

If it wasn't, well that's what you need (but any decent kit will include it anyway). Underfloor heating isn't really suitable for controlling with a timer. It's effectively a large, horizontal storage heater. The Schluter-Ditra type above will heat up faster than the traditional system that heats the whole slab of concrete, and may work better with a timer - if that's what you want - but reading the spec (in particular, the claim that it delivers more W of heat into the room), I think it'll cool down very quickly too once you turn it off.

Maybe that matches how you want to use the sunroom, in which case it should be fine, but before you commit, I think I'd try using a couple of small electric heaters in the space (opposite corners to the radiator) adding a total of 800-1200W to the room to see if that small amount of heat gives you the boost that you're looking for. I did something similar in my open-plan back hall/utility room to see if UFH was likely to take the chill off the cold air coming down the stairs. 1kW made a huge difference.

hesker

I came across this website when I was looking at something similar for a bathroom. Have yet to try it out but it gives you another supplier to consider.

http://www.ezewarm.co.uk/

colm_mcm

Does it have to be tiles?

Calahonda52

OP: IMO the wrong approach to what appears to be a periodic requirement for additional heat as there will be, as well as the cost issue, a temporal response mismatch vis a vis the heating requirement.
If wedded to elec, consider infrared elec heaters.
Also maybe, only maybe, consider upgrading glazing only.
The above assumes that the room , and the rest of the house are pretty airtight: have you checked the corners of the rubber seals on the glazing, after 12 years I suspect some shrinkage, leading to increased uncontrolled air permeability.

macnug

justagirl wrote:

I am taking up old tiles and laying new ones. I am considering putting down those electric heating mats under the new tiles in a sunroom. Can these be easily laid directly onto concrete floors and tiler tile over them? I'm looking to buy one with a timer that I use only when its very cold as the sunroom does not retain heat very well (no way around that unfortunately). Has anyone done something similar? If so, any pointers as to where I should buy them (Leinster area) Thanks so much.

I used to sell/fit these years ago. If the heat loss is too great and its the only source of heat in the room the floor may not even get that warm as the heat escapes into the room. If you can, put down insulation tile backing boards that direct the heat back up. Devimats were the best, they are not in Ireland anymore but you can still get them from the UK. Go for the 150w/m2 version for the greatest heat output, plenty of timers to choose from.