Hi all!

I've laid some underfloor heating throughout my bungalow - it's the wet type, not electrical.

I'm going to lay some floor tiles in the bathroom but don't know the best type of adhesive to least interfere with the transfer of heat.

Should I go for a cementious or dehydrating adhesive?

Also, do you have any thoughts on types of tiles, ceramic, porcelain etc?

Also, what about sizes of tiles and grout joints and grout types.

A lot of questions there for a 1st post!

Look forward to the responses... and HELLO!

have you thought about getting a pro to do the tiling

Hello and welcome.

Adhesive.. I would recommend a C2FT-S1 cement based adhesive and a CG2 grout.

Tiles are a personal preference but try to get some not so slippy.. So mat finished porcelains are good..

Grout joints are 3mm min for floors but again depends on tile type for what looks best.

Size of tiles.. again this is a personal choice and choices come in varying sizes..

Originally Posted by Dave

Hello and welcome.

Adhesive.. I would recommend a C2FT-S1 cement based adhesive and a CG2 grout.

Tiles are a personal preference but try to get some not so slippy.. So mat finished porcelains are good..

Grout joints are 3mm min for floors but again depends on tile type for what looks best.

Size of tiles.. again this is a personal choice and choices come in varying sizes..

thanks that's useful - regarding the tile and grout size, yeah understood it is of personal preference. But I've never laid on an underheated floor before, so I wasn't sure if there were any issues with the conductivity of grout, i.e. if it was considered poor you'd want to keep the joints small etc. A similar consideration with tile sizes, but so I gather from your post, there's no such consideration - am I right to assume this? it is just a case of aesthetic rather than any issue of heat transfer?

Adhesive and Grout types - can you give me some trade names for C2FT-S1 and GG2, I normally use BAL green and white star.

I'm a plumber by trade, but have laid many wall and floor tiles in the past so am very comfortable with the job, but like I said, not this specific environment.

Thanks again

Green star and white star are wall tile dispersion adhesives..

C2FT-S1.. Example.. mapei kera-quick..

CG2 Grout.. Example Mapei Ultra colour plus.

Tiles are grout will allow heat to transfer no probs.. BS 5385 states 3mm min grout joint of floors but you can go wider if that is the chosen width..
tile size makes no difference either.. but tiled area does as in regards to expansion joints.. but if the floor is smaller than say 40 sq mtrs then only perimeter joints will be required on a straight forward screed install.

Bal green and white star are dispersion adhesive and are not suitable for what you require.

Originally Posted by Dave

Green star and white star are wall tile dispersion adhesives..

C2FT-S1.. Example.. mapei kera-quick..

CG2 Grout.. Example Mapei Ultra colour plus.

Tiles are grout will allow heat to transfer no probs.. BS 5385 states 3mm min grout joint of floors but you can go wider if that is the chosen width..
tile size makes no difference either.. but tiled area does as in regards to expansion joints.. but if the floor is smaller than say 40 sq mtrs then only perimeter joints will be required on a straight forward screed install.

Excellent - top! Straight forward advice.

QED welcome. Always use flexible cementitious adhesive and grout over underfloor heating - the heat will cause some expansion and flexible is essential.

Bathrooms can get away with (just about) basic ceramic floor tiles, but most of us would recommend any floor to be laid with porcelain, more expesive, but ultimately so much more hard wearing - which means your adhesive must be suitable for porcelain.

A good tile retailer will give you the correct advice on tiles adhesive and grout - that means stay away from B and Q, Focus and Homebase!!!!!!!

Hi and welcome

Is the floor a standard sand cement screed

Originally Posted by whitebeam

Hi and welcome

Is the floor a standard sand cement screed

I wasn't here when the scree went down, but if I said "flo-tex" would that ring any bells? It was something I'd not heard about before and, so I believe, is part way between a scree and a self levelling compound.

We've just bought some Slate tiles - I take it this'll be okay in the debate between artifical vs stone?

Thanks guys, all a great help to me

What is the substrate?

Originally Posted by Ajax123

What is the substrate?

Hi, if you mean substrate as in what's below the scree, then, in order, 15mm polypipe on plastic floor panels, above membrane.

Is slate okay then?

Any advance on the Mapei Keraquick adhesive?

Thanks again

Ajax123 means that he wants to know more about the type of screed.

I hate to say it but I really would give this one to a pro. Slate on UFH. There is a lot that can go wrong here unless you know what you are doing and are still very careful. Laying slate is not like laying ceramics.

When you bought the slate, did the people in the shop advise on stripping/sealing products?

is it Kerakoll H40 Flotex? if so Kerakoll should have a suitable adhesive so you can stick with an entire system. Less to go wrong and fewer companies involved.