Help!: Weight of Limestone & Travertine per square meter?

[des511]

Hi
Great forum with lots of good advice and know how. I am hoping to tap into this now with the question. I have an en-suite with my new loft conversion where the walls are plasterboarded with a skim on top. We had set our hearts on having either Limestone or Travertine tiles on the walls and floors and then I came across this forum where I learnt that a plasterboard wall with a skim can only take a weight of 20kg per square metre. Further reading on the forum seemed to say that the Limestone
or Travertine would be too heavy. Now here is my question, I have a sample of the actual Limestone tile which is 10mm thick and 10cm square.
I weighed the sample and it came out at 180 grams, now using my not too good maths I worked out that it would take 100 of these sample tiles to make one square metre. 100 of these tiles at 180 grams each works out at a total of 18kg which seems a lot less than I have read. Am I completely wrong with this.
Any help or advice would be greatly appreaciated and sorry about my first post being a bit long.

Thanks.

[MICK the Tiler]

Hi Des511,

Welcome to the forums

Don't forget your grout will be a couple of kilos at least per m2 depending on the size of the grout line, so that would put you right on the limit of what the plasterboard can take.

Go around each wall and thump the walls with the palm of your hand and if you hear the sheet rattle against the studs then more screws will need to be inserted about 200mm apart this should give you some extra support for those lovely trav or limestone tiles you desire.

[des511]

Thanks for the welcome and advice. The walls are new and nice and solid so thats a plus. Do you think the way I got around to the 18kg weight is correct? I do really fancy the 10mm limestone.

[MICK the Tiler]

Thanks for the welcome and advice. The walls are new and nice and solid so thats a plus. Do you think the way I got around to the 18kg weight is correct? I do really fancy the 10mm limestone.

In a word "YES"

[deanotile]

your tiles will be fine

[des511]

Thank you all for your help.

[grumpygrouter]

Don't forget that you need to add the weight of the adhesive as well. At around 4kg /m2, I personally would think twice. May be best if you re-boared the walls and DON'T SKIM THE BOARDS.

[Hardibacker Rep]

Hey!

You should use Hardibacker 500 (12mm x 1200 x 800) for the walls...the board is designed to hold 45kg per sqm of tile....

The building regs state no mre than 20kg per sqm on skimmed walls and no more than 32 kg per sqm on plasterboard...by using our board you keep yourself well within the limits....

[des511]

Okay now I am in 2 minds again. If the Limestone works out at 18kg per square metre using my method of weighing the sample and we allow 4kg for grout and adhesive which comes to 22kg. I think I might risk it and when I am in the bath I can stare at the walls with my hard hat on.

[grumpygrouter]

Okay now I am in 2 minds again. If the Limestone works out at 18kg per square metre using my method of weighing the sample and we allow 4kg for grout and adhesive which comes to 22kg. I think I might risk it and when I am in the bath I can stare at the walls with my hard hat on.

Thats 4kg for adhesive and 2kg for grout per m2 - 24kg/m2. Hard hat and body armour may be a better solution, though re-boarding as I previously suggested may be a cheaper option.

[des511]

Thats 4kg for adhesive and 2kg for grout per m2 - 24kg/m2. Hard hat and body armour may be a better solution, though re-boarding as I previously suggested may be a cheaper option.

Anyone know where I can get rust proof armour

[Turkish]

You`ll probably be fine mate. As with most things i would imagine the weight figures are on the safe side. As it`s your bathroom i would personally go for it, if it was for a customer then that maybe a different story

Turkish

[deanotile]

If it was large format ties id be cautious but 10 by 10s no problem

[deanotile]

Thats 4kg for adhesive and 2kg for grout per m2 - 24kg/m2. Hard hat and body armour may be a better solution, though re-boarding as I previously suggested may be a cheaper option.

Do not men to question you but if you get 5 m2 to a 15 kg tub that is 3kg per m2 and you get 40 m2 to 10kg bag that is 3.25 kg per m2 for grout and adhesive.

[des511]

What a great forum with all the helpful advice I have been given so far. The tiles that I am thinking of using are 30.5cm by 30.5cm limestone which are 10mm thick. I am moving away from the same size tile in Travertine as from what I have learned is that I would have to butter the back of the tile to file the holes and also apply adheasive to the wall which would up the weight even more. I have paid a visit to a tile shop and they told me that some of the ceramics weigh more than natural stone. Loks like the only thing that I can put on the wall without risk is paint or wallpaper that looks like limestone

[deanotile]

What a great forum with all the helpful advice I have been given so far. The tiles that I am thinking of using are 30.5cm by 30.5cm limestone which are 10mm thick. I am moving away from the same size tile in Travertine as from what I have learned is that I would have to butter the back of the tile to file the holes and also apply adheasive to the wall which would up the weight even more. I have paid a visit to a tile shop and they told me that some of the ceramics weigh more than natural stone. Loks like the only thing that I can put on the wall without risk is paint or wallpaper that looks like limestone

Do you know the weight of the limestone if it is the same as the trav 18kg the adhesive and grout are 3.25kg that is 21.25kg 1.25kg over the limit (not worth worrying about m8)

[MICK the Tiler]

.5 of a mm come on give me a break. I did a floor a couple of weeks back and the tiles were 453x453 does my head in try to do mental gymnastics for my set-out where do they get these measurements from GEEEEEEZ.

And limestone is supposed to have a rectified edge come on you lousy manufactures get metric and set the saw correcty.

Oh!! and I'd still go for laying your limestone des511

But as others have said there are options but cost will play a big part.

[grumpygrouter]

Do not men to question you but if you get 5 m2 to a 15 kg tub that is 3kg per m2 and you get 40 m2 to 10kg bag that is 3.25 kg per m2 for grout and adhesive.

Most of the bags of adhesive I use are 20 or 22kg, they give approx coverage of about 4-5m2 which is stated on the back. if you are using adhesive in 10kg bags that give 4m2 I would be really interested to know cos it will be much cheaper.

As for tubs, I don't use tubbed stuff for stone. If I do use tubbed stuff, it all depends on the area to be tiled and what coverage I would need - wet areas I use a BAL thinbed/solid bed trowel which uses more adhesive.

[deanotile]

Most of the bags of adhesive I use are 20 or 22kg, they give approx coverage of about 4-5m2 which is stated on the back. if you are using adhesive in 10kg bags that give 4m2 I would be really interested to know cos it will be much cheaper.

As for tubs, I don't use tubbed stuff for stone. If I do use tubbed stuff, it all depends on the area to be tiled and what coverage I would need - wet areas I use a BAL thinbed/solid bed trowel which uses more adhesive.

Try using BAL white star 15 kg will give you 5m2

[grumpygrouter]

Try using BAL white star 15 kg will give you 5m2

White star was the only tubbed stuff I used. As for the question by the original poster, I wouldn't use it on stone, therefore my responses were in relation to using bagged stuff. The general concensus on the forums by much more experienced tilers than me is that you will only get 4 to 5m2 out of a 20kg bag of powder.

As the poster was questioning the max weight of skimmed plasterboard and was wanting to fix travertine, I quite rightly stated that with the adhesive and grout, he would be exceeding the maximum safe limits for that substrate and he needs to think again.

You obviously have a different opinion and that is fine. However, even with your own figures, 3kg of white star per m2 plus his 18kg for tiles still exceeds the safe limits for skimmed plasterboard, not allowing for the additional weight of the grout. If he decides to follow your advice that is his choice but personally if it was my children sat in the bath with the possibility of 25 or 30kgs of tile falling on them because I had ignored valid, correct advice I would be mortified.

[des511]

Now I am scared

[grumpygrouter]

Now I am scared

Wasn't meaning to scare you Des. Weight limits are specified for a reason. Me, as a professional tiler, would not do for a customer what you are looking to do for yourself. It would have serious reprocussions for me insurance wise if anything went wrong.

Going back to my original advise, and bear in mind I don't know what exactly would be involved, I would rip out the skimmed board and put up new stuff. This would pretty much eliminate any weight issues and be safe. if you are going for really heavy stuff, then consider re-boarding with backerboard instead. Screw this to your studs and you can fix up to 50kg/m2.

You always have the option of changing your tiles to small thin ceramics, these will be fine on your skimmed board.

[deanotile]

White star was the only tubbed stuff I used. As for the question by the original poster, I wouldn't use it on stone, therefore my responses were in relation to using bagged stuff. The general concensus on the forums by much more experienced tilers than me is that you will only get 4 to 5m2 out of a 20kg bag of powder.

As the poster was questioning the max weight of skimmed plasterboard and was wanting to fix travertine, I quite rightly stated that with the adhesive and grout, he would be exceeding the maximum safe limits for that substrate and he needs to think again.

You obviously have a different opinion and that is fine. However, even with your own figures, 3kg of white star per m2 plus his 18kg for tiles still exceeds the safe limits for skimmed plasterboard, not allowing for the additional weight of the grout. If he decides to follow your advice that is his choice but personally if it was my children sat in the bath with the possibility of 25 or 30kgs of tile falling on them because I had ignored valid, correct advice I would be mortified.

BAL white star is suitable for fixing natural stone and there is nothing wrong with dispersion adhesives.

[Hardibacker Rep]

rip out the plasterboard.....put in Hardibacker...the whole problem go's away!!

[deanotile]

If the tiles are only 18 kg there is no problem

[grumpygrouter]

BAL white star is suitable for fixing natural stone and there is nothing wrong with dispersion adhesives.

You are absolutely right, White Star will fix natural stone and there is nothing wrong with dispersion adhesives.

Trouble is with dispersion adhesives, they stick by having the moisture absorbed then evaporated away. With a susbtance like limestone or trav, this moisture goes into the tile and then has the possibility of staining the product or bleeding through, giving a not very nice appearance. There are products available that will reduce this bleed and staining problem but they are powdered stuff

Having done my last job of 17m2 of a bathroom with white star, I decided then that it would be the last time I used dispersion adhesive. White Star in particular is a pain to get of tools and the surface of the tiles, but it does stick just about anything.

[Hardibacker Rep]

If the tiles are only 18 kg there is no problem

in regard to the weight i guess but would'nt you rather have the back up of another 18kg weight support instead of 2kg????

Your plasterboarding a shower? When (and I mean when!) the water gets behind the tile its going to degrade the bond...make the paper face of the plasteboard go mouldy....making your grout go that lovely shade of green/black.....mould cant grow on cement!

[grumpygrouter]

If the tiles are only 18 kg there is no problem

Why is that then? I am not trying to be argumentative, I am just trying to understand why you think there is not a problem?

[des511]

The 3 walls that I am Iooking to tile regarding dimensions are
Wall 1 1.8M x 2.1M
Wall 2 1.6M x 2.1M
Wall 2 0.8M x 2.1M

but as you say the problem is not the size of the wall but the strenght of the skim on the plasterboard. The weird thing is that if I would not have come across this forum I would have never thought about the weight issue and would without a second thought put the tiles on the walls.
It makes you think that how many people have done it.
Looks like I will have a busy weekend ahead of me as I have to make up my mind by Monday about what to use. The bathrom will have a bath and not a shower.

Thanks again.

[grumpygrouter]

The 3 walls that I am Iooking to tile regarding dimensions are
Wall 1 1.8M x 2.1M
Wall 2 1.6M x 2.1M
Wall 2 0.8M x 2.1M

but as you say the problem is not the size of the wall but the strenght of the skim on the plasterboard. The weird thing is that if I would not have come across this forum I would have never thought about the weight issue and would without a second thought put the tiles on the walls.
It makes you think that how many people have done it.
Looks like I will have a busy weekend ahead of me as I have to make up my mind by Monday about what to use.

Thanks again.

No problems Des. Good luck which every way you decide to go. Maybe drop us a couple of pics when it's done eh.