Polished Marble, weight, tanking and ongoing maintenance

[eyup]

Hi all,

We really like some some polished marble tiles for our bathroom. Ones in question are Verona Stone Imperials which each measure in as 305 * 475 * 12mm. I cant find a specific weight for this tile online. Appreciate I should have got this when at the shop.

Unfortunately, our walls are all plaster skimmed therefore the advice given was weight will be too much. The suggestion was to knock back to block or use backer board. Both are not appealing for time and cost respectively. However, if it is absolutely necessary it is something we have to think about or change the tile.

We then went to a second shop where we were told backer board not necessary and the weight would be fine on bare plasterboard although it is at the top end of acceptability. We were also told here that some people do exceed by large margins the recommendation for tiles on skimmed walls and many have no problems but obviously whether it lasted 5 minutes or 50 years would be anyone's guess and it was certainly not recommended. This isnt a risk we are willing to take however.

Anyway, I have the following answer the questions:

1) would the above tiles be fine on plasterboard if I nail this into through the existing plaster layer and into the block? ie at 32kg/m

2) if we were then to tank the shower area, will the tanking product still hold the said tile?

3) How long does it actually take to maintain/seal natural marble tiles each year? People say it is a pain but does it really take that long? They do look so much better.

Thank you in advance.

I appreciate any and all help.

Thanks
Neil

 

[tpt]

Sealing it is just a case of using a gloss roller, cloth or brush - its a liquid. really no big deal once a year or so. perhaps a morning\day of hassle.

Weight wise, the shops right. we regularly see mass overweight in installations, and rarely see failures. but we do see failures and of course when they happen you have no redress at all.
Personally, on plaster i'd be concerned, on plasterboard i wouldnt.
If you use a backerboard in the shower, you dont need to tank it, just tape the joints and silicone the corner before tiling.

assuming its a light marble one other word of caution. make sure a white, powdered adhesive is used. you need white to stop bleed through, and you need a powdered addy due to size. The plaster must be primed with acrylic bonding (2 coats) first

being cheeky - if you haven't bought the tiles yet can i ask what you have been quoted? we deal a lot with verona and may be able to save you some £

 

[eyup]

hi tpt. thanks for the reply. very useful. haven't bought yet. have pm'd you (i think). please respond to confirm I worked it correctly and will send you my existing quote. cheers

 

[eyup]

For the benefit of future readers I've posted the problems here so answer may be of help in future. I have also responded to tpt via private message re the quote etc.

Anyway, issues arising, as TPT kindly offered his advice.

Basically we bought from an old couple who have hardly done any work for many years. When we ripped out the bathroom furniture and tiles (cheap ceramic) we obviously made many holes/damage to plaster which has since been patched by an experienced diy'er. On the upper half of the wall we discovered paint under the tiles (def paint not a waterproofing product) so what we have now is half newly plastered & skimmed wall and half painted original plaster which appears sound other than for the paint.

The weight limit on skimmed wall is 20kg/m2 but even on this the paint may be an issue if tiling over with anything but light tiles. I just dont trust the adhesion of the paint.

We would like natural marble tiles but the ones chosen (and on which I have asked TPT to quote) are 12.5mm thick I think. The maximum my research suggests is 32kg on bare plasterboard which will mean boarding out the room. However, my research also suggest that maximum natural tile depth for this weight would be 10mm therefore I am 25% over. The only solution is therefore tile back board which is obviously much more expensive (roughly a factor of 4 -5 by my workings)

However, we have seen conflicting advice on this with some stores saying dont worry it will be fine on new plasterboard/others saying probably not.

So, the options are now:

1) Tile over paint and risk adhesion issue (not really an option in my mind)
2) Scrape off the paint to leave clear plaster and opt for a porcelain, marble effect tile. Problem is likely time consuming plus we dont know how well we will get paint off/it may cause more problems. Tile is also not as good looking as natural option.
3) Plasterboard over the existing surface, mechanically attaching into block work behind existing plaster, again opt for porcelain to be safe.
4) Plasterboard over existing and opt for marble and chance it with the weight.
5) Tile back board over existing and opt for marble but costs are mounting rapidly
6) Chip back all plaster to the base block/brick. Very messy and time consuming.

Additional problem is that we are working to small tolerances therefore any additional boarding makes thing very tight (but I have to remeasure) for the shower enclosure which may overlap the edge of the window so couldnt work.

Any thoughts would be appreciated as best option. Really it hinges on whether new plasterboard would support the weight of 12.5mm marble tiles. I think it is at best at the upper limits.

Thank you.

 

[tpt]

I may be adding to your woes a little here i'm afraid. All the weight limits your being quoted\have researched are correct, but you may be forgetting to allow for adhesive, which as a guide adds 4kg/m2 to the weight.

Additionally, if your looking for a large porcelain tile these may not be much lighter than the marble. Good quality porcelain is very heavy.

I'll speak to verona tomorrow for you and get an exact weight if i can. at least then you'll know where you stand on p/board.

If your going to overboard, you may well be better off just using Knauf Aquapanel - this is a cement backerboard that comes in larger sheets than normal tile backerboard. it can be cheaper. It does need mechanical fixing though. You could use this if you overboard or chop back to brick and then overboard.

or you could do this - http://www.nomoreply.net/overboarding SOLID.htm. Not the cheapest option either way though i'm afraid! as a guide we sell this for around £7.50 each, depending on volume

No need to tank in the shower area, just tape the joints.

 

[jctilingservices]

overboard with hardiebacker,then use your marble tiles, tile, addy and grout weight should not be an issue then