Hi.. I am tiling around a bath floor to ceiling with large slate tiles... The supplier provided Larsen Grey Flexible Rapid Set Adhesive C2F S1 - 20Kg. This has not provided good adhesion to the plaster walls and I'd had to remove tile and ahesive and reaply.... Came home last night and one of the tiles had fallen off the wall and damaged the new whirlpool bath.... I therefore looking for help on the best adhesive for the tiles and any kind of primer I should use on the walls first before laying tiles... I'm not at all impressed with the Larsen product, but the supplier said it was great and that they use it for all their swimming pool jobs etcm so I thought it would be suitable for use around bath and shower area... Thanks for any advise... Dean

Last time I used Larsen it was a good adhesive. I never had issues at all.
Did you prime the walls before tiling? If so can you explain your priming methods ?

Also you say you are fixing 300 x 600 slate to plastered walls. Are you aware of weight limits for tiling ?

if your walls were plastered, the slate tiles would be too heavy anyway.

I use Larson's all the time and haven't had a single failure....... As above, slate too heavy for plaster and-or priming issue.

As the others slate could be too heavy for the plaster and not adhesive problem

was the plasterboard top coated
and i agree with others the slate is to heavy for plasterboard

Originally Posted by Sir Ramic

Last time I used Larsen it was a good adhesive. I never had issues at all.
Did you prime the walls before tiling? If so can you explain your priming methods ?

Also you say you are fixing 300 x 600 slate to plastered walls. Are you aware of weight limits for tiling ?

Yes... I think it's 20kg per m2... each tile is around 4.8kg

Originally Posted by Stewart

I use Larson's all the time and haven't had a single failure....... As above, slate too heavy for plaster and-or priming issue.

Hi... I didn't use any primer... I called Larson technical today and they said that I needed to use normal setting adhesive rather than rapid and also use a primer with the product.... What I'm after is some guidance then... I want to tile the walls from above the bath to the ceiling... what do I need to do? Apply a primer, remove the plaster and tile directly onto the plasterboard or board over the existing plaster so that the substrate provides enough key for suitable adhesion....? Also, what is the best adhesive for the job? I have used Ultra before on limestone flooring and got good results... As I say, I'm not impressed with Larson.... I am removing the tiles tomorrow to avoid any more accidents! Thanks, Dean

Hi Dean..

You say the tile fell off.. was any adhesive on the tile or just on the wall.? and what method if fixing did you use.?

Originally Posted by Dave

Hi Dean..

You say the tile fell off.. was any adhesive on the tile or just on the wall.? and what method if fixing did you use.?

The adhesive was fully on the tile and none was left on the plaster... adhesive was applied to the tile with a notched trowel and tile applied to wall with a twist... what I am thinking is that the plaster needs to be primed or I need to place backer board on the wall to be 100% sure... what adhesive do you recommend...? mapei looks the best to be... Thanks, Dean

Ok, So no primer was applied..

what finish is on the plaster.. is it dusty or is it quite shiny..?

Originally Posted by Dave

Ok, So no primer was applied..

what finish is on the plaster.. is it dusty or is it quite shiny..?

Hi Dave.... Probably more dusty than shiny as it I sanded the matt emulsion off it before tiling.... Thanks, Dean

Ah right.. what has happened is the dust has prohibited adhesion of the adhesive..

prime with a suitable acrylic primer( instructions on the bottle) and then start again.. make sure you get full contact and i do hope you have got your weights correct..

Also dean, let us know how it goes mate.. maybe some pics hey.?

Originally Posted by Dave

Ah right.. what has happened is the dust has prohibited adhesion of the adhesive..

prime with a suitable acrylic primer( instructions on the bottle) and then start again.. make sure you get full contact and i do hope you have got your weights correct..

Also dean, let us know how it goes mate.. maybe so me pics hey.?

Thanks Dave.. will do - I have some pics before the tiles started falling off! I think I will be belt and braces with this one and install some no more ply backing boards... I'm not worried about damage to the new whirlpool (although a pain), more worried if someone had been in the bath and a 5kg slate tile would have landed on their heads - not a good situation... I'll opt for backing boards and Mapei adhesive for the walls and save the Larsen for the floor area... Pics to follow... Thanks, Dean

If you want, Mapei kera-flex maxi is a good one for stone.. work clean and seal before you grout..

Look forward to the pics.. if you need any more advice then just ask dean.. always someone about to help..

Dean, I use Ultra addy, never had a failure with it (yet!)

Originally Posted by Dean Pedder

... I'm not worried about damage to the new whirlpool (although a pain), more worried if someone had been in the bath and a 5kg slate tile would have landed on their heads - not a good situation...

How often do I say this?!?!?!?!?

And it's becoming more of a problem, due to the fact stone is the popular choice at the mo it seems.

I wish tile outlets would STRESS the importance of choosing the right products and going through the right procedures. A simple A4 sheet with a bunch of advice with every stone sale would pay dividends. The customer could leave this with the tiles and sure enough even an amateur tiler would see something's wrong if it was?

Though as Mike said (I think it was in this post?) - the tiler has to always be to blame really as it's only them that can stop the job due to a reason that can affect the job. The customer, the shop, the manufacturers, nobody else can be fully to blame like the tiler can be no matter what's gone wrong on a job.

Would just like to add, go easy on Larsen. If you had used Mapei or any other brand without a primer, the same thing would have happened.

It wasnt a fault with the product but a fault in the substrate prep.

Hope you get it all sorted

Larsen is a sound family-owned Irish firm. I don't think anybody was knocking them per say. I think this is an adhesive we'll see more of in the future.

Originally Posted by Dan

Larsen is a sound family-owned Irish firm. I don't think anybody was knocking them per say. I think this is an adhesive we'll see more of in the future.

No... not knocking the Irish, I'm part Irish myself!.... The fault as I see it is between the manufacturer and the supplier... I told the supplier my requirements, that I was laying the large format slate on both floor and walls... therefore I should have been advised the use of a suitable latex base primer as well... obviously they are dealing with Larsen and are buying quantities of their adhesives, therefore it is only fair that the Larsen's agent in the UK should make the supplier aware of any ancillary or complimentary products... it's in the interest of the supplier and the manufacturer to make sure that 5kg tiles stay on the wall and not land on anyone's bonce... and let's face it, for the sake of an extra £10, would have saved damage to my new bath and a whole heap of time removing tiles off walls, then adhesive off tiles then relaying the same tiles again... let alone the cost of the wasted adhesive... Thanks, Dean

Originally Posted by Dean Pedder

Yes... I think it's 20kg per m2... each tile is around 4.8kg

That tile weight with those dimensions give a weight /m2 of 26.7kg add the weight of the adhesive and grout and you have exceded the safe working limit of a plastered wall by 50%......proceed with caution!

Originally Posted by grumpygrouter

That tile weight with those dimensions give a weight /m2 of 26.7kg add the weight of the adhesive and grout and you have exceded the safe working limit of a plastered wall by 50%......proceed with caution!

Hi grumpygrouter.... thanks for the info... as part of my belt and braces approach I have now ripped all the drywall out and I'm in the process of fixing no more ply backing board to the blocks... I will prime this afterwards... the boards will now give me more than enough adhesion for the tiles... I've opted for Ultra, rather than the Larsen, as I've used this before and it has never let me down and is good to work with... Dean

Hi dean,

I have read the posts above and there are some great guys in here with a massive amount of knowledge. I think no matter what adhesive had been used i think there probably would of been a problem on way or another as the product is only as good as the substrate you are tiling onto. A poor substrate will always lead to a failure or problem. Think definatley a good idea to use a ply backing boards due to the weight. - Mat

I would'nt use ply on walls and certainly not in wet areas IMO

he's using no more ply whitebeam