Fixing up an underfloor heating problem

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timmmay

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#112777 20-Dec-2012 08:23

I just had an expensive new bathroom installed, but the underfloor heating stops 10-15cm short of the toilet, one of the most important areas to have heating IMHO. I'd like to have it heated up to the toilet, or very close, and slightly down the sides of the toilet. Right now on a cold day the difference between the main part of the floor and there the front of your foot is when you're standing there is 6-8 degrees, a huge difference. The room is eight square meters, more or less.

The bathroom company (who are generally excellent) have said it's very very difficult to take up tiles, add more heating loops, then put it back down. They said the heating is a factory sealed unit, and while it might possible it's difficult, and it voids any warranty.

I've come up with an alternate plan. We take up a few tiles (3-5) around the toilet, put a metal sheet over the heating mat and over the unheated areas, then put new tiles down. That transfers the heat sideways, then lets it go up through the tiles. This would result in the same amount of heat being spread over a larger area, so it won't be as warm, but it will be a lot better than dead cold.

Does this sound like a good solution? Can anyone see any downsides I can't spot? Should I insist on them adding more heating element instead of this workaround?

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#735275 20-Dec-2012 08:33

If you are taking the tiles up, then just put a bigger heating mat in - you've done most of the work already by that stage.

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timmmay

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#735278 20-Dec-2012 08:36

Good idea, but I wasn't clear about what I'm doing, first post edited. We're taking up only 3-5 tiles, around a square meter, the room itself is 8-10 square meters - it's a pretty big bathroom.

Niel

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#735292 20-Dec-2012 09:27

In our new house we decided against underfloor heating and just use bathroom mats. You can buy very good quality for less than your proposal. I'd also be concerned about the metal plate significantly increasing the area of a low wattage heating element and you are likely to get significant improvement. Underfloor heating is designed on the principal that the whole floor requires more or less the same power to heat up.

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timmmay

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#735294 20-Dec-2012 09:31

Initially we were going to use lino, which doesn't need heating or mats. Early on we upgraded to tiles, which due to the increased heat conduction means either heat the floor or use mats. We don't want mats as it spoils the look of the room, and we spent a lot more money to get tiles and under floor heating put in. I really don't think they've done their job to an acceptable standard, so this is a warranty issue, not an additional cost to me, though I'll be a bit flexible on costs.

That part of the floor, if anything, needs more heating not less. So this solution while better than nothing is probably still not going to fully satisfy me. I may end up asking them to work out how to add to the heating mat, though they seem very reluctant to do that.

Am I being reasonable, or unreasonable?

wellygary

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#735295 20-Dec-2012 09:32

You may damage the wired heating loops when you bring up the tiles. From memory the heating loops are rather fragile things, and while they should be under a protective seal, depending on the strength of the tile grout, this may be damaged if you try to lift large chunks of tiles......

timmmay

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#735296 20-Dec-2012 09:35

Yes they told me that there's a risk of damage taking tiles up. I'm not happy with the job they've done in this area though, so I consider fixing it their problem. They seem willing to work with me, but the general response is "this is the way we always do it, no-one else has ever complained". I don't consider that answer good enough.

bazzer

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#735300 20-Dec-2012 09:44

timmmay: Initially we were going to use lino, which doesn't need heating or mats. Early on we upgraded to tiles, which due to the increased heat conduction means either heat the floor or use mats. We don't want mats as it spoils the look of the room, and we spent a lot more money to get tiles and under floor heating put in. I really don't think they've done their job to an acceptable standard, so this is a warranty issue, not an additional cost to me, though I'll be a bit flexible on costs.

That part of the floor, if anything, needs more heating not less. So this solution while better than nothing is probably still not going to fully satisfy me. I may end up asking them to work out how to add to the heating mat, though they seem very reluctant to do that.

Am I being reasonable, or unreasonable?

I don't think you're being unreasonable. If the bathroom was expensive then I would expect the result to reflect that. Why would you spend a lot of money on a bathroom you're not happy with?

I think at the very least they should have told you which areas of the floor would end up being heated. If they did, then your bad. If they didn't, then it's on them. Why would you heat the whole bathroom and neglect the toilet, the area that's probably used most?

Getting them to fix it on the other hand, will be a mission.

timmmay

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#735306 20-Dec-2012 09:51

If you're sitting on the toilet, your feet are warm. If you're standing the back of your feet are warm, but the front cold. If you move your feet around or back at all they're cold. It's mostly a problem at night, if you wander in half asleep.

Just for reference the cost from the bathroom firm was around $40K, which was stripping the room and rebuilding it, levelling the floor (it had a 4cm fall toward the outside), new hot water cylinder up in the ceiling instead of in the body of the house, new electrics with the whole room RCD protected, new plumbing, a new smaller window and a few weatherboards outside, attic stairs and an insulated box around them (huge heat loss otherwise), and good quality materials and fittings without going crazy - eg methven taps, good quality NZ made. That doesn't include the cost of the tiles, lighting, window, or cupboard doors, which were another $6K or so.

Jaxson

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#735358 20-Dec-2012 10:52

What's the nitty gritty of it all?

ie, when you levelled the floor, how was that achieved?
What's the floor material made of now, under the tiles that is.

It's electrical underfloor heating, so if you add another pad/circuit (probably the easiest option) then how will they integrate that back into the existing solution? As in can they run the connecting cables back nicely? You don't want separate switches/controls for different sections of the room I expect.

Easiest solution is to rip up the tiles in the immediate area, but quite honestly, depending on how adhered they are, there would be a pretty realistic chance of breaking the existing underfloor heating circuit. Depends on how tough the heating pad is, and how nicely you could separate this from the tiles. On a good day it would remain intact, but depending on where this aligned with the tiles you were bringing up, it could be risky. Worst case is you have a nice foot area around your toilet, and then nothing over the remainder of the floor!

Really it's potentially a fair bit of work. Means successfully removing existing tiles, laying new heating pad, connecting new heating pad electrically, re tiling, re grouting, resealing and a lot of hoping nothing goes too wrong along the way.

timmmay

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#735373 20-Dec-2012 11:20

The floor's wood. They used that liquid leveling compound, heaps of it. Above that is some kind of board which insulates, then waterproofing, another layer of something, then the heat mat, another compound, and then the tiles. I'm pretty sure that's right, I didn't need to pay attention to the details.

Adding another heat mat is tricky. The cable would have to be run up a wall, through the ceiling, then down, which would be a fair bit of work. How to connect it to an existing controller would be another issue, if it's even possible. If it was possible to patch the existing heat pad that would be ideal.

I see the risk of damage to the heat pad. Honestly if they'd done it properly the first time we wouldn't be having this problem. They missed the area outside the shower too, but since we have a bath mat that we hang on the heated towel rail most of the time that's not a problem.

Goosey

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#735383 20-Dec-2012 11:36

Have you considered "expol", this will keep the heat in espcially when it sounds like you have a very cold house.
Did you replace insulation in the walls when renovating the bathroom?
Has the celing cavity got decent insulation?

I agree with a previous poster... a decent floor mat would keep your toes warm... or a good pair of slippers !

timmmay

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#735385 20-Dec-2012 11:40

Insulation isn't the problem, under floor heating is. The room temperature's fine, but unheated tiles feel very cold as heat's transferred very quickly from your foot to the tile.

My house is old but it's now very well insulated. It had no insulation when I bought it, but now it has under floor (including under the bathroom), wall (blown in, but as I renovate I put in pink batts, done in the bathroom), the ceiling has loose fill wool with pink batts over the top for a total of about 20cm insulation, the attic stairs have an insulated box over them that cost me $500, and I have two heat pumps. The house stays warm overnight, even with no heating, but the floor never gets that warm.

wazzab

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#735394 20-Dec-2012 11:48

I went through this exercise recently. As I was spending a load of dollars also, my floor heating guy and I got a copy of the floor plan and shaded in the bits we, as the client, wanted to be warm. I did bathroom, laundry and toilet, all with there own heat pads and wall controllers. He said there was no point in heating 10cm or so next to anything as you don't really stand there, ie along the walls, along benches and tubs in the laundry and under the wall hanging vanities, so we avoided all this area. I agreed with his recommendations and it also saves power not heating additional floor space. Our toilet heating is about 15cm back from the bowl and only in front and not around the sides or back, and its fine. Surely if you are standing that close you'd be knocking you knees on the bowl. We have 2 young boys anyway who are messy, so tend to have a toilet matt to catch drips, and this does also keep your feet warm. I can sympathise with yourself and also the installer though - you for getting cold toes, and him for installing what I would consider standard practice. For the amount of dollars you are talking about I would have taken a very close interest at installation time. Its a major to fix the problem unfortunately.

nickb800

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#735398 20-Dec-2012 11:52

timmmay: The floor's wood. They used that liquid leveling compound, heaps of it. Above that is some kind of board which insulates, then waterproofing, another layer of something, then the heat mat, another compound, and then the tiles. I'm pretty sure that's right, I didn't need to pay attention to the details.

Adding another heat mat is tricky. The cable would have to be run up a wall, through the ceiling, then down, which would be a fair bit of work. How to connect it to an existing controller would be another issue, if it's even possible. If it was possible to patch the existing heat pad that would be ideal.

Couldn't they run the wiring for the additional heating mat under the house, and then feed up the wall through the same route as the existing heating mat?

timmmay

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#735417 20-Dec-2012 12:03

wazzab: I went through this exercise recently. As I was spending a load of dollars also, my floor heating guy and I got a copy of the floor plan and shaded in the bits we, as the client, wanted to be warm. I did bathroom, laundry and toilet, all with there own heat pads and wall controllers. He said there was no point in heating 10cm or so next to anything as you don't really stand there, ie along the walls, along benches and tubs in the laundry and under the wall hanging vanities, so we avoided all this area. I agreed with his recommendations and it also saves power not heating additional floor space. Our toilet heating is about 15cm back from the bowl and only in front and not around the sides or back, and its fine. Surely if you are standing that close you'd be knocking you knees on the bowl. We have 2 young boys anyway who are messy, so tend to have a toilet matt to catch drips, and this does also keep your feet warm. I can sympathise with yourself and also the installer though - you for getting cold toes, and him for installing what I would consider standard practice. For the amount of dollars you are talking about I would have taken a very close interest at installation time. Its a major to fix the problem unfortunately.

I wish they'd done that. I had to push them to get any plans at all, and it wasn't that details. Staying 10cm from walls and such is a good idea, but with the toilet you don't always stand where you expect - trying not to be crude you want any drips to go where they should!

nickb800: Couldn't they run the wiring for the additional heating mat under the house, and then feed up the wall through the same route as the existing heating mat?

Well, yes, of course they could! I don't know if the controller could power two though - unless they run in series or parallel effectively.

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