Travertine walls tiles: Advice for DIYer

[Gazz]

Hello

First time poster, but have done a lot of reading and picked up a LOT of tips from the forum: thanks.

I'm a reasonably good (if slow) DIYer. I am fitting a new bathroom suite and was going to ceramic tile, but have bitten the bullet and bought travertine which I think will look classier once done.

The bathroom is pretty small, a 1930's semi, solid/lat walls (no plasterboard) & I'm looking to half tile except for the wall which runs the length of the bath which I want to do full height and make a feature, mixing in some mosaic.

Problem is on this wall in particular, I'm paranoid about the weight of the travertine (about 30Kg/m2). Various individuals at a few shops have said it'll be fine, just fix over the plastered wall (solid external brick wall). However having read a bit about the loads involved I've bought some HardiBacker for this wall only, but have the following questions:

1. I,m going to lat the wall with 2" X 1.5" wood, fixing this vertically to the existing brick wall using screws & rawplugs. What centres should I use & what size screws/plugs would you recommend.

2. I'll fix the backerboard to the wood lats using 40mm aquapanel ceramic screws: all I could get: will these be OK? Is it best to tile onto the rougher side of the backerboard, or smoth side?

3. I'll fix the tiles to the backerboardo I need to prime this with anything before fixing the travetine (probably going to use Mapei cement based powder adhesive).

If I do the above, do I need to be concerned about the weight issue.

With regard to the half tiled walls. I've removed all paint and stripped these back to the bare finish plaster. The plaster is solid and as it's half tiled I'm not quite so paranoid about the weight concerns. However:

4. Do I need to prime these before tiling and if so with what?

I'd be grateful for any advice.

Gazz

 

[beanz]

Just curious, but why are you only boarding out the one wall? It's still the same weight/square metre on the walls that are only being half tiled!?!

 

[Gazz]

Just curious, but why are you only boarding out the one wall? It's still the same weight/square metre on the walls that are only being half tiled!?!

I'm pretty sure that the walls will generally hold the weight of the tiles, as I said they are solid, not plasterboard and in good condition. (please correct me if I'm wide of the mark here) However I am a little paranoid (perhaps unjustifiably) about the one wall where I will be tiling to ceiling height. A tile falling on your toe is one thing, but a tile falling on your head whilst sat in a bath is something else completely!

Perhaps I'm going overboard, but I'm concious that the "chain" is only as strong as the weakest link, hence I would like to get things right from the safety aspect.

Gazz

 

[beanz]

Perhaps I'm going overboard, but I'm concious that the "chain" is only as strong as the weakest link, hence I would like to get things right from the safety aspect.

Gazz

I don't think you're going overboard at all. The weakest link in your chain is that Plaster is only rated to take 20kg/m².

 

[Gazz]

I don't think you're going overboard at all. The weakest link in your chain is that Plaster is only rated to take 20kg/m².

Beanz

thanks for the response.

For the half tiled walls then should I be strapping these and using hardibacker, as I have for the main fully tiled wall. The problem would then be that the wooden lats, plus hardibacker, plus the tile thickness would bring the lower part of the wall out by around 2.5 inches.

Just thinking of the physics, is it not the case that a fully plastered wall would effectively be self supporting where the load is partially applied ie the load is downward (gravity): as I am only tiling the bottom half of a fully plastered wall, would the adhesion of the plaster "sheet" above the tiles not contribute to the overall resistance to the downward pull of the tiles. Just thinking aloud.

Gazz

 

[beanz]

The problem would then be that the wooden lats, plus hardibacker, plus the tile thickness would bring the lower part of the wall out by around 2.5 inches.

I agree, that would look more than a little odd.. :yikes:

Have you thought about taking the plaster back to the block/brick and dot & dabbing Plasterboard? Bare Plasterboard can take 32kg/m².

No idea about the Physics of it really, and how the forces work, but hopefully someone on here will know a little more about that side of things. I've seen Travertine tiles put up with tubbed gear on Plaster a year ago that are still standing, but would i recommend it??? Nope.

 

[Gazz]

Cheers Beanz

Can anyone else offer any advice/opinion/solution to this and also advice re my original questions in the first post.

Thanks
Gazz

 

[grumpygrouter]

Cheers Beanz

Can anyone else offer any advice/opinion/solution to this and also advice re my original questions in the first post.

Thanks
Gazz

Having just read your post carefully, I must tell you that you will be greatly overloading the plaster wall if you want to fix Travertine to it. Plaster is only "safe" up to 20kg/m2 and that includes adhesive and grout. There is a good chance your tiles will be 25 -30kg/ms alone before adding adhesive and grout. This is something you need to consider carefully before you proceed. tilersforums.com CAN NOT CONDONE OVERLOADING SUBSTRATES WITH INAPPROPRIATE TILES.

Further to your question, it is necessary to prime the plaster with and acrylic primer before tiling if using a cement based adhesive.

 

[Gazz]

Having just read your post carefully, I must tell you that you will be greatly overloading the plaster wall if you want to fix Travertine to it. Plaster is only "safe" up to 20kg/m2 and that includes adhesive and grout. There is a good chance your tiles will be 25 -30kg/ms alone before adding adhesive and grout. This is something you need to consider carefully before you proceed. tilersforums.com CAN NOT CONDONE OVERLOADING SUBSTRATES WITH INAPPROPRIATE TILES.

Further to your question, it is necessary to prime the plaster with and acrylic primer before tiling if using a cement based adhesive.

Grumpy

Thanks for this. I realise that you are quoting the recommended stresses but do wonder what these are based on (curiousity, not trying to be a clever arse).

Surely the wall overall area, tiled area and tile location must also be considered.

For example, take a plastered wall say 10m by 10 m and travertine weighing 30kg per square metre. There would surely be a vast difference in the forces exerted on the plaster if for example you tiled the full 10 x 10 sq metres, as opposed to, say, tiling an area of that wall 10cm by 10cm. The 10 cm square would be the same weight per square metre, but the total force on the wall (plaster "sheet") would be only 0.3Kg, compared withthe total force exerted on the fully tiled 10m by 10 m wall of 3000Kg.

Equally if the same wall was tiled for the top 5 linear metres only, there would be an unsupported force of 1500Kg. However if the wall was tiled from the bottom up for the first 5 metres, the tiles would have the same weight, but as you are starting from the floor, and assuming that the gravititational pull is downward, there is surely an element of support from the floor boards which in turn sit on the joists.

This is why I was questioning the safety of half tiling (about 900 cm floor upwards) on the plastered wall (I will be using a backer board when I tile the full wall).

Please don't take this the wrong way, I'm not some sort of physicist, nor am I trying to be a clever arse: just trying to understand the logic behind the quoted figures.

Many thanks to you and Beanz for your replies.

Gazz

 

[beanz]

Gazz, there should be an expansion gap at the bottom, the tiles don't sit on the floor. I can see what you are saying though, and watch this thread with interest.

 

[Gazz]

Gazz, there should be an expansion gap at the bottom, the tiles don't sit on the floor. I can see what you are saying though, and watch this thread with interest.

Beanz

Thanks for this: why is there a requirement for an expansion gap at the bottom? Presumably this is for the tiles not the substrate.

What is the recommended gap if I were tiling from the floor up two tiles (450mm each). Would a gap be required?

Again I don't understand the logic behind this. Could you not close the expansion gap with flexible grout, effectively offering the tiles support from the floor upwards as per my argument above. You might argue, "but if you grout you lose the expension gap". My counter to this would be what happens to "internal" tiles which need to expand, for example the middle tile of a block of 9 tiles arranged 3X3. The only expansion that this tile would be allowed would be via the grout which surrounds it on all four sides.

Even if no expansion gap was left at all on the bottom tile, the tile would be surrounded by grout on three sides, allowing 75% of the expansion of the centre tile in the example above.

I realise that you guys will have practical experience on your side and will no doubt get sick of newbies questioning everything, but I am trying to gain an understanding.

Thanks for your patience.:mad2:

Gazz

 

[beanz]

The expansion gap is there to allow for expansion/contraction of the substrate. You'd usually use silicon on the gap, although i have seen flexible grout used. I haven't got the figures, but flexible grout only allows for the tiniest movement really. That said, i've been told by a site tiler, and a Mastic Man, that they grout behind the silicon, as it gives a much neater finish. To my mind, there's very little point leaving an expansion gap, filling with grout, then applying silicon just so it LOOKS like there's a proper expansion gap!?!

I understand what you are saying about the tiles in a block of 9 etc, but it doesn't work like that... The wall and the floor are different materials so will expand/contract at different rates. It's at these joints that there will be the greatest movement, and there's a chance that your tiles will be pushed off the wall. That's not to say that they definitely WILL be pushed off the wall, just that there is more than an acceptable chance. At the end of the day, you won't be suing yourself, so the option is yours hehe!

 

[DHTiling]

Hi gazz...some good advice from the members above.....

You can also just attach 6mm hardi straight to the wall without using battens you know...

Here is a pdf for doing just that...

HardieBacker EN installation 200810 masonry walls.pdf

if you did the whole wall then you can skim the top half to decorate.

 

[grumpygrouter]

Grumpy

Thanks for this. I realise that you are quoting the recommended stresses but do wonder what these are based on (curiousity, not trying to be a clever arse).

Surely the wall overall area, tiled area and tile location must also be considered.

For example, take a plastered wall say 10m by 10 m and travertine weighing 30kg per square metre. There would surely be a vast difference in the forces exerted on the plaster if for example you tiled the full 10 x 10 sq metres, as opposed to, say, tiling an area of that wall 10cm by 10cm. The 10 cm square would be the same weight per square metre, but the total force on the wall (plaster "sheet") would be only 0.3Kg, compared withthe total force exerted on the fully tiled 10m by 10 m wall of 3000Kg.

Equally if the same wall was tiled for the top 5 linear metres only, there would be an unsupported force of 1500Kg. However if the wall was tiled from the bottom up for the first 5 metres, the tiles would have the same weight, but as you are starting from the floor, and assuming that the gravititational pull is downward, there is surely an element of support from the floor boards which in turn sit on the joists.

This is why I was questioning the safety of half tiling (about 900 cm floor upwards) on the plastered wall (I will be using a backer board when I tile the full wall).

Please don't take this the wrong way, I'm not some sort of physicist, nor am I trying to be a clever arse: just trying to understand the logic behind the quoted figures.

Many thanks to you and Beanz for your replies.

Gazz

Hi Gazz, not sure about the physics either but the max weight capability is from the plaster and plasterboard manufacturers themselves, and is incorporated into BS guidelines for tiling. There may well be no problem at all by overloading the substrate, all I am saying is that it is not a practise that can be condoned by this forum. As part of the forum "mangement" if you like, it would put us in a potentially difficult situation if we said "yes it will be fine" and then your wall falls down.

Views of individual members are not necessarily the views of Tilersfirums.co.uk and we can not be held responsible for their "advice". it is only advice after all and you are free to chose and act upon anyones advice as you seem fit.

Hope you understand my point.

 

[smurf21]

Basically the lads are saying we dont know the whys and wherefores of the rec tile weights to substrate ratios they are the guidlines that we have to follow as proffesional tilers as stipulated by board and tile and addy manufacturers if we dont follow them and worse case scenarios happen then all product guarantees are void, so we follow them no point questioning them unless its really important to know why. We then pass on this info free of charge to all who ask whether you follow said advice or not is completly up to the individual poster,whether or not you agree with the info given it is the correct info to which we as pros adhere to.
It may seem sometimes when we spout out a lot of technical info that we dont really know wot we are talking about, but it only seems that way.