Should I use undertile insulation board?

[apul]

Hello. We are going to tile a large kitchen diner sometime soon. The existing floor is concrete which is going to be reasonably level (after I apply more compound). I don't think there will be insulation boards under the screed due to the age of the house.

Whats your opinion on undertile insulation boards? I know they are generally used in combination with underfloor heating (but we wont be having it, mostly due to the cost). The area is about 22m-sq.

Ideally we would use 6mm deep board due to the level of the back door. Could get away with 10mm.

Will they save us money on heating and will the floor feel less cold if we use them?

How easy are they to lay and lay onto and do they cause problems with movement and loosening tiles?

Lots of questions I know. But its about time I did something about it.

Many thanks!

 

[alternativetiles]

To buy 22 square metres of insulation board at 10 mm thick will cost about £350 ish plus the extra adhesive and time to wack it down say another £100 ish ?? depends how you value the time. I would be in two minds whether it would pay off to fit it without underfloor heating. The savings in loss from your central heating through the floor in your circumstances would take quite a few years to recoup the cost of using the boards. If you saved say £60 a year it will take 7-8 years to get to £0-0.

I would probably say forget it. Just my opinion I am sure someone will argue differently.

Lay onto a bed of adhesive, easy to lay - well sort of. Stagger the bond.

Yes it may feel a tad different but the only real way is to use underfloor heating. It is a very cost effective way to heat a room, frees up the radiator and makes tiles luurrvly

 

[apul]

Thanks for the reply.
You make good points about the return on the investment which I've been neglecting to think about recently.

Are there any suggestions of brands?
EkoBoard 6mm is on ebay for about £125 for 20m2 http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=250137622740

Any alternatives?

 

[alternativetiles]

I think putting 6 mm down for insulation purposes is a bit of a waste, if you are doing the work and using the adhesive etc you should go 10mm thick.

10mm Insulation boards (example Knauf, Marmox) usually retail around £16 - £18 per square metre. So £350 ish for 22 square metres.

If you are going to go to the trouble go 10mm thick. 10mm over 6 mm is 66% more effecient I would think as 66% thicker.

They don't cause problems with tiling as long as you fit them correctly (laid brick bond and solidly bed to the primed concrete with single part-flexible floor adhesive). When down prime the surface prior to tiling then use single part-flexibile floor adhesive again and flexible grout (polymer modified or use an admix)

Why don't you price up undertile heating while you are going to the trouble? It may not be as dear as you think? If the floor is 22 square metres expect to heat say 14 square metres - maybe less. You don't go edge to edge with undertile heating, you don't put it anywhere where stuff goes on top (under a settee for example). Makes a great selling point if you decide to move house 14 square metres costs around £450 for a complete kit.

 

[joe-90]

Tiles on concrete are horribly cold in the winter. I find them unbearably so, they make your feet and legs ache within minutes. I'm not sure that insulation board would help either as tiles are naturally very cold.

 

[gcol]

Do you not have a pair of slippers?

 

[joe-90]

Do you not have a pair of slippers?

Yep - but I meant when wearing slippers or shoes or trainers. Don't underestimate how cold concrete and tiles can be.

 

[gcol]

I have concrete and tiles throughout my ground floor. No problem.

 

[alternativetiles]

Tiles are poor conductors but will eventually take on some of the room temperature. In my experience having ground floors (inc living rooms) tiled in my last 3 houses it's no problem. In my current house we have the whole ground floor tiled with undertile heating throughout and it is awesome Hygenic, clean, warm, blah blah.

 

[gcol]

Just out of interest, do you need any other forms of heating in these rooms? If not, how do the running costs compare to regular central heating? If so, what do you reckon it costs to run anyway? Thanks.

 

[alternativetiles]

No other heating is required, I use the 200w per sq.metre system. I can not tell you how much it is to run at home as we have not been living there long enough yet but at the shop I have it heated the same in one of the rooms:-

Room = 20 square metres, concrete floor - no insulation 200 year old building

11 square metres is heated and is enough to keep the whole room warm and into adjacent two rooms either side.

It costs me an extra £30 per month to heat it, being on (thermostatically of course) all day in winter months. I have the room very warm as it is a shop and want to demonstrate how good it is to sell it (stat set at 29 degrees).

A domestic house done in the same area would be a lot less bearing in mind most people are out at work and will not have it on pipeing hot all day to sell it

 

[alternativetiles]

I should add bathrooms are perfect to heat as they run at only 300w when on full (2 square metre 150 w system) and are cosy and keep the rooms from misting up so much.

When you mop it dries so quickly too

 

[gcol]

Nice one, sounds the business.

When you mop it dries so quickly too

lol I can just imagine the scorch marks on the mop.