is C2TE tile adhesive ok for bathroom?

[Laubi]

hi all,

bought this as it was the only standard set adhesive in the shop at the time. Only just realising this is not an S1/S2.

Is this ok to use for bathroom wall/floor? be using porcelain tiles on hardiebacker boards

Mapei Standard Set Plus Grey Ceramic & Porcelain Tile Adhesive - 20kg | Wickes.co.uk

Mapei Standard Set Plus Grey Ceramic & Porcelain Tile Adhesive - 20kg

www.wickes.co.uk

 

[Wayners]

Have you read the data sheet? That's what I'd do.
Look it up online

 

[Joe Fixit]

Have you read the data sheet? That's what I'd do.
Look it up online

Yes I have but I have no idea what to look out for here.

 

[Wayners]

That's the safety data sheet. Called coshh. That's not the data sheet.

COSHH stands for the Control of Substances Hazardous to Health regulations,

You want the data sheet. That's is instructions. Where to use. How to use. How to mix ect

 

[Joe Fixit]

It's the only datasheet on the site. And I can't seem to find anything on this product on Google!

I guess for bathroom floor/wall tiles, it has to be flex(S1/S2)?

 

[Wayners]

https://cdnmedia.mapei.com/docs/librariesprovider12/line-technical-documentation-documents/ceramic-pocket-guide.pdf?sfvrsn=e6a355c6_0

Hope that worked.
It's the brands ceramic tiling guide

 

[Joe Fixit]

https://cdnmedia.mapei.com/docs/librariesprovider12/line-technical-documentation-documents/ceramic-pocket-guide.pdf?sfvrsn=e6a355c6_0

Hope that worked.
It's the brands ceramic tiling guide

Thanks, thats really useful. But problem is that the one I got doesn't have any of those brand/model names.

It does say on the packet it's suitable for showers and use even in underwater. But I just didn't know if I really need to get one where it's certified S1/S2 as I see people say best to use flex adhesive

 

[Wayners]

Also this information

https://cdnmedia.mapei.com/docs/librariesprovider52/line-technical-documentation-documents/tile-installer's-manual.pdf?sfvrsn=73141c7b_4#:~:text=Minimum%20requirements%20of%20substrates,Minimum%20width%20of%20joint

Hopefully it will help you. There are other downloads.

They also should have a technical helpline.


I think you should use flexible not standard.
Standard is for solid floors

 

[simplesteve]

You definitely need to use a Flexible on the floors. As there’s no ‘flex’ in the products name, I would err on the side of caution and presume it isn’t.
( and I take it you’ve noticed it’s Grey ? )

 

[freddiemercurystwin]

Why don't you just ring up Mapei, all these kinds of manufacturers have technical departments and get these kinds of queries every day, they'll tell you the best one to use rather than you second guessing 0121 5086970. Weirdly I can't see that exact product on their website, which is where you would find the data sheet.

 

[Joe Fixit]

Thanks all. Will give them a try but suspect it's not flex.

You definitely need to use a Flexible on the floors. As there’s no ‘flex’ in the products name, I would err on the side of caution and presume it isn’t.
( and I take it you’ve noticed it’s Grey ? )

Do wall tiles need flex? Just wondering if the bag Ive got isn't flex, whether I can still make use of it

 

[Laubi]

I rang technical support and they say that this does not have the S1 flex certificate.

But he also advises that I do not need flex on a bathroom floor if laying it onto hardiebacker.

Any opinions on this please?

 

[simplesteve]

For the sake of an extra fiver a bag, are you going to risk not using flex on the floor ? I've tiled loads of floors over the years, and never used anything but flex - even if it doesn't need it.
But you deffo don't need flex for the walls, in fact the extended time this bag claims actually makes it ideal for a diy wall tile adhesive.
( as long as your grouting with grey )

 

[Joe Fixit]

For the sake of an extra fiver a bag, are you going to risk not using flex on the floor ? I've tiled loads of floors over the years, and never used anything but flex - even if it doesn't need it.
But you deffo don't need flex for the walls, in fact the extended time this bag claims actually makes it ideal for a diy wall tile adhesive.
( as long as your grouting with grey )

Thanks. That's good then. I can use it for the walls and get a new bag for the floor. Thanks!!

 

[BuiltByChemistry]

Good question — the EN 12004 classification confuses a lot of people because the codes look similar but mean very different things.

C2TE means: cementitious (C), improved bond strength ≥1 N/mm² (2), reduced slip (T), extended open time of 30 mins (E). Quality general-purpose adhesive.

S1 / S2 means: deformability classification — S1 = 2.5-5mm transverse deformation, S2 = above 5mm. This is the FLEX class, completely separate from the C2TE designation. An adhesive can be C2TE without being S1, like the Mapei product you bought.

When does S1/S2 actually matter? Three situations:
1. Substrates with movement potential — plywood, OSB, suspended floors, thin screeds (yours: hardiebacker is rigid, movement is minimal)
2. Underfloor heating — thermal cycling needs flex tolerance
3. Large format porcelain above 40x40cm — rigid adhesive concentrates stress at edges

Tech support's advice — no flex needed on hardiebacker for porcelain — is technically correct IF: no UFH, format under 40x40cm, residential traffic only. The board is dimensionally stable enough.

simplesteve's "spend the extra fiver" advice is also valid because it removes the ambiguity. C2TE-S1 covers all bases — same product, slightly more expensive, no edge cases.

For your bathroom (porcelain on hardiebacker, no UFH, standard format) — C2TE works. For peace of mind on a job you'll only do once — use the flex.

One detail the data sheet matters for: open time. Mapei standard C2TE has 30 mins, fast-set has 10-15. Standard set is what you want for porcelain in a small bathroom — gives you room to adjust.

I write a weekly newsletter called Built by Chemistry — easy to find on Google.