can I 'skim' or build out a hollow dip using tile adhesive?

[Tunni]

I'm tiling a 6ft x 8ft plasterboard wall (The plasterboad is dot and dabbed and also dry wall screwed, so it's extremely well fixed) with 400 x 400 x 12mm natural travertine. The wall is fairly plub and level but a straight edge reveals a fairly large central 'hollow dip' of up to 5mm.

Can I true the wall up by using some rapid set floor tile adhesive and running a feather edge board along the surface. I know 5mm isn't much but when I start tiling I'd prefer the wall to be spot on - that way I only have to concentrate on tiling and not struggle with a large variation in the depth of the adhesive.

Hope that makes sense.

Tunni

[whitebeam]

Yes you can, just use a straight edge to make sure it's flat

[wetdec]

Yes you can prime it first..... do not skim if your using travertine m8

..

[Alan.P]

My question is if dot and dabbed why is there a dip, is it an over tightened screw pulling it in or was it just a bit of over zealous tapping ?

Otherwise, as per the rest

[brian c]

serate the wall with adhesive and back butter the tile and this will sort it.

[lucius]

Why is it dot and dabbed and screwed? screwed into what.
Lucius.

[beanz]

Will 12mm Travertine not be too heavy for Plasterboard?

[Tunni]

Having read through dozens of threads I'm told it's a no no to tile onto skimmed plaster. So I dot and dabbed plaster board onto walls and screwed as well into the existing plaster/brick to fix it. (The 5mm dip was due to fixing the last 18inch of PB...I discovered the original skim was out at the edge and even with next to no addy it caused the 'hollow'

Moving on Wetdeck - Can you elaborate, you mean prime as in brush primer or do you mean with addy? And there appears to be disagreement with Whitbeam who says yes I can skim (using addy as explained NOT plaster, just in case you were at crossed purposes)

[beanz]

Tunni, you can skim with addy (ideally Rapid Set), but you need to prime 1st with an Acrylic Primer.

I still think you'll be exceeding weight limits though. Plasterboard can only take about 32km/m².

[tileform]

Found this link from an earlier topic

Tiles and Adhesive Weight Per Square Metre - THE TILE SOURCE

[Oli]

Having read through dozens of threads I'm told it's a no no to tile onto skimmed plaster.

You can tile onto skim plaster, but your
A) wasting time and money skimming the plasterboard as its not neccessary to tile and
B) reducing the amount of weight per m2 from around 32kg/m2 to 20kg/m2.

Id skim flat the void with addy and then tile as others have advised.

[doug boardley]

your question is perfectly reasonable tunni, and yes, much better to take the dip out using rapid set addy and a straight/feather edge

[redmist6]

You can tile onto skim plaster, but your
A) wasting time and money skimming the plasterboard as its not neccessary to tile and
B) reducing the amount of weight per m2 from around 32kg/m2 to 20kg/m2.

You crack me up..oli..always rely on you for the specific scientific details.....i love it!!

I thought i was the only one!!.....

[Tunni]

Great info guys, Thanks again for selflessly passing on your hard earned knowledge.

Regarding the tile weight/substrate guides, I appear to be over with 12mm travertine. (Oli why didn't you read my mind ...and let me know earlier!!) Having said that, stats of this nature are usually very conservatively rated. Based on that there must be a fairly healthy reserve....I hope so, as it's one I'll be using! Obviously by paying careful attention to optimise all the other aspects of good tiling practice I should be able to minimise any potential problems.

Tunni

PS. If anyone has any construction/timber/carpentry questions I'd be only too happy to help if I can (I benefited from a family of three generations of skilled carpenters - whilst all my mates were out playing as kids, I'd be helping my dad in his workshop... never bloody forgave him for that!! LOL)

[grumpygrouter]

Great info guys, Thanks again for selflessly passing on your hard earned knowledge.

Regarding the tile weight/substrate guides, I appear to be over with 12mm travertine. (Oli why didn't you read my mind ...and let me know earlier!!) Having said that, stats of this nature are usually very conservatively rated. Based on that there must be a fairly healthy reserve....I hope so, as it's one I'll be using! Obviously by paying careful attention to optimise all the other aspects of good tiling practice I should be able to minimise any potential problems.

Tunni

PS. If anyone has any construction/timber/carpentry questions I'd be only too happy to help if I can (I benefited from a family of three generations of skilled carpenters - whilst all my mates were out playing as kids, I'd be helping my dad in his workshop... never bloody forgave him for that!! LOL)

Substrate weight limits are given for a reason. They may or may not be conservative and we, giving advice on these forums, can not recommend that they are ignored. Certainly as a pro tiler, I would not put those tiles onto an inappropriate substrate as a law suit may follow if anything happened. What would REALLY stop me doing so though was the thought of several Kg of tile and wall falling down onto a small child, certainly hurting and possibly killing said child. This to me is an unacceptable possibility and I would not put anyone at risk by doing so.

I assume the tiling is in your own home? If so then you have the right to carry on if you wish. If you do so, good luck and I hope nothing untoward comes of it.

[Dave Ramsden]

lol dude just tile the wall, 5mm is nothing!

PS, not happy bout dot n dab PLUS screwed!!!!

[Tunni]

[quote=grumpygrouter;175080]Substrate weight limits are given for a reason. They may or may not be conservative and we,

I agree on the first part Russ, but not the second. It would be unthinkable for the upper limit to not have a reserve and where safety is an issue a very healthy reserve at that. By that I'm not implying that thay can be taken with a pinch of salt, but under full and careful consideration (as I indicated in my post) it would be reasonable to go over to a slight degree.

Good point though, and although I am more than satisfied that my plasterboard (especially the way it’s solidly fixed) will take the weight. I did do the calculations just so I don't maim or mortally injure my beautiful 4 yr old daughter Nicole and my 2 yr old boy Leon. - After all they are joint heirs to my overdraft and it would be a tad upsetting to see them crushed under the weight of ancient travertine stone as it parts company with the aformentioned substrate due to the criminal negligence of their dad! In any case I need my son Leon to continue to disgrace or tarnish the family name as I no doubt have!

..And if I may play the Devils advocate for a moment - just for the record, in the known universe, how many unsuspecting little one's have tragically met their demise at the sudden and catstrophic failure of a substrate... whilst innocently playing in the bathtub? -

Dam if you didn't get me thinking though (and I hate doing that!) So, I did the maths:-

1 off 450 x 450 travertine stone tile = 4.7Kg/tile, which equates to:-
4.938 tiles for 1sq m. Now 4.938 x 4.7kg = 23.2Kg Add adhesive and grout @ 6Kg/m (thanks for the stats Oli) and we have a total weight of 29.2Kg Plasterboard weight limit = 32Kg….. Leaving me with 2.8kg spare! So Hallelujah and praise be to the Lord....my kids have been spared!

Regards to all
Tunni

PS ....Any reason for the name 'Grumpy' Russ!!!

PPS Dave Ramsden, What don't you like about Dot n dab AND screws... It's only a precaution, dead easy to do makes it bomb proof - on the belt n braces principal! Or did I misunderstand you? Or put it like this, a few years ago someone asked a pilot why only planes with 4 engines were allowed to fly accross the Atlantic. The Pilot replied "because they don't make airplanes with more than 4 engines"!

PPS. BTW, My (some say warped and twisted!) sense of humour is intended to raise a smile and never to cause offence. I add this note in respect and as a precautionary measure, for those granite tough, hard nosed pro tilers who may be hiding an overly sensitive or far more gentle side to their character. ..you know who you are!

[beanz]

I agree on the first part Russ, but not the second. It would be unthinkable for the upper limit to not have a reserve and where safety is an issue a very healthy reserve at that.

I wouldn't be so sure mate. When i first started coming on this forum, the weight limit for Plaster Render was being quoted at 25kg/m², and in that time it's been lowered to 20kg/m². I can only assume the reason it's been lowered, is that it was found to be incorrect due to a fail at below 25kg/m². To be fair, this is an assumption on my part, but is it any less valid than your assumption that there is a healthy reserve?

[Dave]

I wouldn't be so sure mate. When i first started coming on this forum, the weight limit for Plaster Render was being quoted at 25kg/m², and in that time it's been lowered to 20kg/m². I can only assume the reason it's been lowered, is that it was found to be incorrect due to a fail at below 25kg/m². To be fair, this is an assumption on my part, but is it any less valid than your assumption that there is a healthy reserve?

Can you link me to where it states that members etc have advised that tiling to plaster skim the limit is 25kg....i don't ever remember that bieng mentioned..

[grumpygrouter]

[quote=Tunni;176075]

Substrate weight limits are given for a reason. They may or may not be conservative and we,

I agree on the first part Russ, but not the second. It would be unthinkable for the upper limit to not have a reserve and where safety is an issue a very healthy reserve at that. By that I'm not implying that thay can be taken with a pinch of salt, but under full and careful consideration (as I indicated in my post) it would be reasonable to go over to a slight degree.

Good point though, and although I am more than satisfied that my plasterboard (especially the way it’s solidly fixed) will take the weight. I did do the calculations just so I don't maim or mortally injure my beautiful 4 yr old daughter Nicole and my 2 yr old boy Leon. - After all they are joint heirs to my overdraft and it would be a tad upsetting to see them crushed under the weight of ancient travertine stone as it parts company with the aformentioned substrate due to the criminal negligence of their dad! In any case I need my son Leon to continue to disgrace or tarnish the family name as I no doubt have!

..And if I may play the Devils advocate for a moment - just for the record, in the known universe, how many unsuspecting little one's have tragically met their demise at the sudden and catstrophic failure of a substrate... whilst innocently playing in the bathtub? -

Dam if you didn't get me thinking though (and I hate doing that!) So, I did the maths:-

1 off 450 x 450 travertine stone tile = 4.7Kg/tile, which equates to:-
4.938 tiles for 1sq m. Now 4.938 x 4.7kg = 23.2Kg Add adhesive and grout @ 6Kg/m (thanks for the stats Oli) and we have a total weight of 29.2Kg Plasterboard weight limit = 32Kg….. Leaving me with 2.8kg spare! So Hallelujah and praise be to the Lord....my kids have been spared!

Regards to all
Tunni

PS ....Any reason for the name 'Grumpy' Russ!!!

PPS Dave Ramsden, What don't you like about Dot n dab AND screws... It's only a precaution, dead easy to do makes it bomb proof - on the belt n braces principal! Or did I misunderstand you? Or put it like this, a few years ago someone asked a pilot why only planes with 4 engines were allowed to fly accross the Atlantic. The Pilot replied "because they don't make airplanes with more than 4 engines"!

PPS. BTW, My (some say warped and twisted!) sense of humour is intended to raise a smile and never to cause offence. I add this note in respect and as a precautionary measure, for those granite tough, hard nosed pro tilers who may be hiding an overly sensitive or far more gentle side to their character. ..you know who you are!

I am glad that you have taken my infomation on board and taken the sensible step of weighing your tiles to find out how heavy they are. In this case you have discovered that you are within the safe limits for the substrate that you are tiling on to and i am pleased that you are not going to be risking danger because of weight issues.

I take your point that there may well be a reserve built into the boards but we (certainly mods and admin) members on here will not recommend that these limits be exceeded in any circumstances as it would be "difficult" legally if the worse should happen. As it is you own property and your own family that is being exposed to any potential danger then that is entirely your concern and you make your call as you see it.

I am called Grumpy just as an amusing screen name as I had some issues when learning my trade regarding grouting...lol...anybody that knows me knows that I am anything but...

[beanz]

Can you link me to where it states that members etc have advised that tiling to plaster skim the limit is 25kg....i don't ever remember that bieng mentioned..

I said render not skim Dave, and my bad... It was 28kg not 25kg: All the questions I asked when i joined - Answered

[Dave]

I said render not skim Dave, and my bad... It was 28kg not 25kg: All the questions I asked when i joined - Answered

Ok..you used the phrase plaster render...not sand/cement......

Now we know what you meant..

[beanz]

Ok..you used the phrase plaster render...not sand/cement......

Now we know what you meant..

Not sand and cement, sorry my terminology isn't great lol! I'm talking about Skim and Set (which i've always refered to as a Plaster Render).