Adhesive, Grout And Sealant Queries With Slate And Ceramic Tiles

[ruffryder]

Hi fellow tillers!

I’m not a DIYer, more an individual who has begun research and supply of materials to our fitter to renovate our bathroom (conventional bath tub, toilet, sink and shower tray ie no part of it is a wet room). I’m hoping you knowledgeable guys out there can assist with my queries and approve or suggest alternative solutions.

Our fitter wants to properly screw down the tongue and groove floorboards to the joists before applying Ardex X 7001 adhesive (is flexible apparently) to bond the Marmox 12.5mm insulation boards on to it (I don’t like ply). He may lay a self levelling compound, then lay the Warmup loose undertile wire (is this a good brand amongst the 10 or so other brands out there?) and slap down some more Ardex X 7001 addy and bond 10mm honed and calibrated slate to it. The slate tiles will then be grouted with Ardex-Flex FS grout, cleaned and two layers of Lithofin Stain Stop Sealer will be applied.

He prefers to seal as stated above rather than to seal the slate before and after the grout has been applied. Does this matter? Is this a minor issue I am worrying about?

I am struggling to opt for a wall adhesive for the 60x30cm ceramic tiles. One wall is new stud wall with plasterboard and another will have more of the 12.5mm Marmox insulation boards. The other walls will have the new ceramic tiles laid straight over the old ceramic ones (cardboard grid based stud wall behind). Is there a decent powder based adhesive which can be applied to all of these surfaces? Doesn’t have to be by Ardex! Someone has suggested Ardex D30 addy but that’s a ready made paste and am therefore reluctant to use even if it is made by Ardex. The same Ardex-Flex FS grout will be used for the ceramic tiles, any issue here?

Is it also necessary for me to purchase Arditex NA wet and dry stuff to hide the undertile heating cables?

Lastly, a non-tiling question, our fitter wants to mount the extractor fan to the ceiling and connect the 4” flexible pipe into like an “n” shape so that it exits through the soffit outside. Problem is I want to attach a 6” fan due to the size of the bathroom (and it’s a quiet fan too!) but the 4” flexible pipe is going to restrict airflow isn’t it and probably labour the motor? Are rectangular flexible pipes available by any chance?!

I would appreciate your thoughts and help on the above.

Thanks in advance.

 

[Tecnik2000]

Hi Ryder, :welcome: ,A part answer...your flooing intentions sound fine to me though I'll say I'm not fully conversant with all the products first hand .It appears you have a pro doing the works.I believe the slate should be sealed prior to grouting though to avoid staining.As for the over tiling I'd let a more experienced fitter advise. Just to say Ardex mixed D30 is good gear & suitable for the wetter areas. As for the extraction 6" down to 4" will be fine as the air flow will not strain the motor , just increase the exhaust flow, unless it's really high volume, having said that the type of external vent is relevant to reducing the volume of flow more than the bore.I always grind existing tiles with a 4" grinder to scabble the surface to aid adhesion prior to over tiling to remove the glaze if essential to leave .

 

[Rich]

Hello and :welcome:

I dont use Ardex myself but many of the guys on here do so it must be good stuff. I use Mapei and swear by it . The tiler you have in seems to know what he is doing (thats a very good start). I would defo advice sealing before grouting as stated above, some seal before laying the tiles and some seal after but it is a very good idead to seal before and after grouting not only to reduce staininf but also to make sure you dont miss any (it is easily done). As for the adhesive for the ceramic tiles, I wouldnt use a tubber adhesive, Id go for a cement based single part adhesive. As I use Mapei Id recommend Keraquick. Finally, have you thought about removing the existing tiles? It is very risky to tile over tile without knowing what the wall is like behind. The tiler should be aware of the substrate and the max weight for it.
I hope some of that essay was helpful... :lol:

 

[grumpygrouter]

he ardex D30 is a dispersion adhesive and is not suitable for tiles of your size. You need a cement based adhesive. Ardex X77 (I think) should be suitable......tiling over tile is something that can be fraught with potential difficulty. Remove the old tiles first if you possibly can.

 

[Daz]

Ardex 7001 is good gear for wooden floors. I would not bother applying slc prior to fixing the UFH. Use Ardex NA slc after the UFH has been installed and then fix the slate. I would probably continue to use Ardex 7001 as it is a single part addy that performs as well as a 2 part. My preference is always to apply a coat of sealer (usually Lithofin Slate Seal) before grouting and then another coat after grouting - that is what works for me.

With regards to the walls, I would deffo not use the D30 adhesive as this is a dispersion adhesive and is unlikely to fully cure beneath a 600 x 300 tile. I would recommend using Ardex X7G+ or Mapei Keraflex maxi. You need to be sure of prepping the existing ceramic tiles correctly, i.e. sugar soap / degreaser, scoring, priming etc., personally, I'd get 'em off and do the job thoroughly.

Ardex FS is a nice grout (& lots of colour choice) but make sure that the grout joints do not exceed 4mm.

Good luck,

Daz

 

[Daz]

he ardex D30 is a dispersion adhesive and is not suitable for tiles of your size. You need a cement based adhesive. Ardex X77 (I think) should be suitable......tiling over tile is something that can be fraught with potential difficulty. Remove the old tiles first if you possibly can.

X77 is brilliant adhesive but very expensive compared to X7G+ which will do the job well, IMO.

 

[grumpygrouter]

Thanks Daryl. Didn't know if it was still available.

 

[ruffryder]

Woah! Thanks for all the quick responses guys. The agreement between the fitter and I is that he tells me how he's going to do it and I go research reputable brands, make enquiries, decide, find the cheapest retailer and buy it!

During enquiries I've heard various different things out there, my iniative become undecided over a few things and gratefully received second opinions of you guys who do this stuff for a living.:8:

I knew there was a good reason why many people seal natural stone before and after grouting. In this instance I'm hoping it wont be so much of an issue as the slate is very dark in colour as will be the grout so any stains which may occur will not be visible (so I like to think). I'm pleased you guys like the sound of the fitter though, he certainly inspires confidence in me and will try persuading him sealing the slate as recommended without looking like I'm telling him how to do his job!

The fitter is reluctant to fit the 6" fan to the 4" flexible pipe because the output of it (280m^3/hr) is high and feels exhaust flow is likely not going to be fast enough to keep up. One way to find out? rrr:

With the wall addy I need does it not matter that it's of the flexible variety when I assume it doesn't need to be with the ceramics?
The tiler is reluctant to take the old 30+ year tiles off because he's worried that the plasterboard behind it will get damaged and those particular stud walls are not of the pine wood baton construction either (ie cardboard mesh/grid).

The Ardex X77 stuff is like double the price :yikes: of Mapei's Keraquick but does sound the part what with its rapid setting. Bugger another dilemma!

 

[doug boardley]

as the others have advised, if your tiler is worried about the substrate if he removed the old tiles, replace the substrate with new plasterboard or tile backer board

 

[grumpygrouter]

Woah! Thanks for all the quick responses guys. The agreement between the fitter and I is that he tells me how he's going to do it and I go research reputable brands, make enquiries, decide, find the cheapest retailer and buy it!

During enquiries I've heard various different things out there, my iniative become undecided over a few things and gratefully received second opinions of you guys who do this stuff for a living.:8:

I knew there was a good reason why many people seal natural stone before and after grouting. In this instance I'm hoping it wont be so much of an issue as the slate is very dark in colour as will be the grout so any stains which may occur will not be visible (so I like to think). I'm pleased you guys like the sound of the fitter though, he certainly inspires confidence in me and will try persuading him sealing the slate as recommended without looking like I'm telling him how to do his job!

The fitter is reluctant to fit the 6" fan to the 4" flexible pipe because the output of it (280m^3/hr) is high and feels exhaust flow is likely not going to be fast enough to keep up. One way to find out? rrr:

With the wall addy I need does it not matter that it's of the flexible variety when I assume it doesn't need to be with the ceramics?
The tiler is reluctant to take the old 30+ year tiles off because he's worried that the plasterboard behind it will get damaged and those particular stud walls are not of the pine wood baton construction either (ie cardboard mesh/grid).

The Ardex X77 stuff is like double the price :yikes: of Mapei's Keraquick but does sound the part what with its rapid setting. Bugger another dilemma!

Keraquick will be fine. Don't bother with the Ardex if you don't need it.

Big heavy tiles stuck onto tiles are asking for trouble in my opinion. You need to be extremely careful that you don't overload the wall and it all comes crashing down around your ears...and potentially hurting somebody. Your decision though. Is your tiler happy being liable if it does?

 

[ruffryder]

Keraquick will be fine. Don't bother with the Ardex if you don't need it.

Big heavy tiles stuck onto tiles are asking for trouble in my opinion. You need to be extremely careful that you don't overload the wall and it all comes crashing down around your ears...and potentially hurting somebody. Your decision though. Is your tiler happy being liable if it does?

The only advantage of the Ardex X77 over Mapei's Keraquick is that it bonds quicker. Assuming the bond itself is just as strong once set then I may as well save some cash and stick with the Keraquick.

Tiler seems confident the wall will take all the weight but I'll double check with him. But has warned if I really do want the old tiles off he'll charge additionally for that as its extra labour. The current ceramic tiles are very thin, perhaps 4mm and 10x10cm.

Out of interest has anyone ever heard or witnessed a stud wall come crashing down because it was overburdened of the weight of the tiles??!

 

[Rich]

The curing time doesnt affect the bond strength. The stud wall wouldnt come down but if the wall is skimmed behind the exisiting tiles the weight of the new tile could be to much and the skim could come away from the wall taking everything else with it. It is down to the tiler and yourself. :smilewinkgrin:

 

[ruffryder]

Hi guys

I think I've thought of a solution to fitting the extractor fan I want. If a 6" duct pipe can't be bent into a "n" shape through the ceiling, over the wall and out the soffit because there isn't enough space between wall and roof tiles why not use a "Y" piece on the 6" ducting with a couple of 6" to 4" reducers on the end and have two 4" exhausts through the soffit and hey presto problem solved? :smart:

Also, I have noticed Marmox boards (along with Wedi) though recommended to me by Ardex are not the cheapest of insulation boards. On the internet they all appear the same, including material and construction wise as other boards ie Knauf Aquapanel, PCS, Elektra Thermopanel, No More Ply, etc so why not stuff brand snobbery and purchase it from a cheaper brand? :snobby:

Am I missing something here or are all backing/insulation boards exactly the same? I don't understand the price disparity?

 

[ruffryder]

Hi Guys

Another update for those interested!

I went for the Marmox boards in the end as the construction of the aforementioned boards above appear the same (with exception of No More Ply and I think Knauf Aquapanel) and Marmox turned out to be one of the most competitively priced insulation/hardibacker board I could get hold of.

It was highly recommended I binned the idea of my best efforts to get a 6" fan to blow through 4" ducting so I went for 4" inline fans by Soler and Palau which could transfer as much air quietly as its normal 5-6" fans.

I couldn't obtain Ardex FS grouts due to my desired quantities not being large enough and was informed Mapei Ultracolour Plus grout was significantly better so plumped for this, but why better I am not sure?

However, I opted against brilliant white grout in Mapei Ultracolour having read too many reviews/opinions of it looking grey which swayed my mind and chose Dunlop Anti-Mould Microban Brilliant White grout instead.

As for the wall adhesive of the large ceramic wall tiles required to go on existing tiles, Marmox boards and plasterboard he swears by the use of Palace ready mixed addy - apparently the tiles wont slip and will bond like hell yet not bond so quickly that he'll have more than 10 seconds to put them on!:incazzato:

I'm a little apprehensive of ready mixed addy from what I've read and may have to bite the bullet and remove existing wall tiles as even Mapei Keraflex only allows tile on tile if new tiles are less than 900cm^2 (30x60cm = 1800cm^2 )

 

[grumpygrouter]

Do not use ready mixed adhesive for tile on tile!!! :no: :no: