problem tiling onto bonding plaster

[cowgomoo]

Hi y'all, I know this is a big no no but what is the exact reason behind the wisdom. Is it a chemical thing or a strength thing or just what precisely ? My prospective client is assured by the plasterer that it is ok as he has done it loads of times before but I want / need the job and don't want to walk away from it so if you could give me the precise reason I would be most appreciative.

Cow.

[Sir Ramic]

Too much suction.

[Sir Ramic]

Have a look around adhesive sites and plaster sites and you will find info to back you up. Print it off and show the client.....get ready to make an enemy of the plasterer though !

[cowgomoo]

Hi man thanks for that but can't you just tell me lol. Cow

[Scott]

It says in the data sheet from the plaster manufacturer that its not suitable to tile to, that should be enough for your customer.

[Alan.P]

Hi man thanks for that but can't you just tell me lol. Cow

LINK


Simples

[Rad2474]

Do you tell the plasterer how to plaster? no! if it goes wrong (and you know it could) it'll be your fault, i think you answered your own question knowing that you can't do it. But can't fault you for asking why gotta learn somewhere and no better place than here about tiling.

[whitebeam]

You can use thistle dri coat backing to tile direct to Thistle Dri-Coat

[Dave]

It isn't stable enough to tile directly to.... tell the plasterer to stick to his own trade... plonker.

[pjc]

Just shows that he hasn't got a clue about his own job yet he is telling you yours it beggars belief what does he know about banking?

[Scott]

It isn't stable enough to tile directly to.... tell the plasterer to stick to his own trade... plonker.

Is that a trade? Rodney must have been well qualified!

[andy allen]

the last one i had told me to p.v.a the bonding and it will be fine...............i told him to shove his trowel where the sun dont shine

[doug boardley]

bonding coat will retain moisture fom your addy and the expunge it, making your addy like powder

[Scott]

What if you control the suction with a variety of coats of primer? First coat 5:1 second 12 hours later 3:1 etc

What would you do to it to skim?

[jay]

i think the issue is with strength of the bonding plaster (top coat i think) you can stick to the surface but it cant hold any weight so it lets go

[whitebeam]

If you soaked bonding in sbr you could probably be safe, The finish depends how long the base coat was applied...

With multi finish now which is a slow setting plaster should be applied the same day while the undercoat has moisture to allow the finish to set properly...but if the basecoat has dried out and a finish is used the basecoat will pull the moisture out of the finish and weakin it and make it unstable to the base coat.

For sand/cement undercoat the finish should be applied the next day to the basecoat to allow set/cure and must be applied while the moisture in the undercoat allows the two to bond together.

These determine how good the finish will be for tile weights, there are many more reasons for failure, age of plaster being one of them.

[newton&stockley]

sorry to say but the adhesive manufactor's state as long as you pva 5:1 beforehand you shouldn't have any problems. I always ring the tech departments if im not sure.... they are the one's that offering the 25 year guarantee. the real reason not to tile onto bonding is it absorbs the moisture from the adhesive. If the client is still not happy and doesn't want any exta wok just get them to sign a weiver. Hope this helps

[Dave]

sorry to say but the adhesive manufactor's state as long as you pva 5:1 beforehand you shouldn't have any problems. I always ring the tech departments if im not sure.... they are the one's that offering the 25 year guarantee. the real reason not to tile onto bonding is it absorbs the moisture from the adhesive. If the client is still not happy and doesn't want any exta wok just get them to sign a weiver. Hope this helps

Which one recommends this then..?

[Colour Republic]

It's funny because only 2 days ago I had an arguement with a guy who hasn't done a lot of work for me over tiling on to bonding.

In a bathroom we are doing he asked the plasterer not to skim the back wall above the bath as it was being tiled, I turned up on site and asked why it hadn't been. Usual arguement "I've been doing it for 40 years..." I skimmed it myself there and then, went to the pub and we met up with 3 or 4 other builders.. all told me I was talking out my arse, one chipped in they had just been on a new site were the tilers had gone straight on to bonding in 25 new bathrooms, another said last year they tiled Trav straight on to bonding in a £25k bathroom as if the price made it ok...

I was up against it! But I love the iPhone...

"...If plastering to provide a background for tiles, avoid polishing the surface. Polished plaster should be roughened and a suitable primer used. Tiles should not be applied directly to Thistle undercoats, with the exception of Thistle Dri-Coat."

http://www.british-gypsum.com/PDF/DS...ing%20Coat.pdf

1. "When it is known in advance that tiles are to be fixed to a plastered wall, it is essential that there should be good adhesion between the undercoat and the plaster finish coat. Tiles should only be fixed to the finish coat and must not be fixed directly to a gypsum undercoat."

Tiling to Gypsum Plaster

[Phil Hobson]

sorry to say but the adhesive manufactor's state as long as you pva 5:1 beforehand you shouldn't have any problems. I always ring the tech departments if im not sure.... They are the one's that offering the 25 year guarantee. The real reason not to tile onto bonding is it absorbs the moisture from the adhesive. If the client is still not happy and doesn't want any exta wok just get them to sign a weiver. Hope this helps

pva??????????

[newton&stockley]

we just tile on what we are told too, yes its not ideal but we didn't want to lose a massive contract.

[newton&stockley]

sorry sbr

[doug boardley]

we just tile on what we are told too, yes its not ideal but we didn't want to lose a massive contract.

I'd rather lose a massive contract than a good reputation. I always walk if people insist I tile onto bonding.

[Sir Ramic]

sorry to say but the adhesive manufactor's state as long as you pva 5:1 beforehand you shouldn't have any problems. I always ring the tech departments if im not sure.... they are the one's that offering the 25 year guarantee. the real reason not to tile onto bonding is it absorbs the moisture from the adhesive. If the client is still not happy and doesn't want any exta wok just get them to sign a weiver. Hope this helps

Shouldn`t is not the same as wont in my book !

And waivers are not worth the paper they are written on depending on how good the solicitor is .

[Scott]

Shouldn`t is not the same as wont in my book !

And waivers are not worth the paper they are written on depending on how good the solicitor is .

Shouldnt there be a NOT in there neale?

[Sir Ramic]

Shouldnt there be a NOT in there neale?

ok ok kick a man while he is down

[newton&stockley]

ok lads, i know you shouldn't but I wasn't going to turn down 10 barn conversions. They supplied the materials and i can't remember which one but I was there when he rang the manufacturer when they said it would be fine, what I am suppose to do??????

[whitebeam]

Can't believe someone did'nt ring British Gypsum who make the stuff for advise.

[Dave]

ok lads, i know you shouldn't but I wasn't going to turn down 10 barn conversions. They supplied the materials and i can't remember which one but I was there when he rang the manufacturer when they said it would be fine, what I am suppose to do??????

You said

I always ring the tech departments if im not sure.... they are the one's that offering the 25 year guarantee.

Only one comp offers that length of guarantee.. so is that who you phoned..?

[newton&stockley]

i don't think so