Hi
I'm looking for some opinions on using cement based adhesive on gypsum
plastered (skimmed) drywall?
I'm doing my first paid tiling job (for a family member) she got all
the material the supplier knew where the tile was to be fitted
(plastered drywall) he supplied a cement based powdered adhesive
It says on the bag "not to be used on gypsum based plaster" I asked
him about this and he said its fine to use it he has sold tons of the
stuff and never had a problem.
My sister in law (the client) is happy enough to use it she says he
should know what he is talking about, as it is his job.
To make things worse there is a shower that is to be tiled and the
substrate in the shower area is skimmed plasterboard (he says it is
perfect for this as it is a flexible adhesive).
I want to use ready mixed adhesive but am a bit unsure because the
walls are studded walls not solid block walls and they will move a
little.
The supplier thinks I'm a donkey and my client thinks I'm over
reacting.
But it says on the bag it's not suitable.
And I have researched it on the web and found something about some
reaction between cement and gypsum.
Should I just do the job with what he supplied and keep my opinions to
myself?

(william) wrote in message . com...
Hi
I'm looking for some opinions on using cement based adhesive on gypsum
plastered (skimmed) drywall?
I'm doing my first paid tiling job (for a family member) she got all
the material the supplier knew where the tile was to be fitted
(plastered drywall) he supplied a cement based powdered adhesive
It says on the bag "not to be used on gypsum based plaster" I asked
him about this and he said its fine to use it he has sold tons of the
stuff and never had a problem.

I guess thats how easy it is to sell something to some folk.

My sister in law (the client) is happy enough to use it she says he
should know what he is talking about, as it is his job.

if only that translated into reality. It should, but doesnt.
Especially when it comes to building.

To make things worse there is a shower that is to be tiled and the
substrate in the shower area is skimmed plasterboard (he says it is
perfect for this as it is a flexible adhesive).

good lord, worst option for that. (Apart from dried porridge.) Plaster
and cement react chemically if they get wet, and the result is they
come apart. You dont use cement on plaster.

I want to use ready mixed adhesive but am a bit unsure because the
walls are studded walls not solid block walls and they will move a
little.
The supplier thinks I'm a donkey

but not for the reason you think.

and my client thinks I'm over
reacting.

is your client skilled or experienced in the business? Client naivety
is normal.

But it says on the bag it's not suitable.

indeed... what does that tell you?

And I have researched it on the web and found something about some
reaction between cement and gypsum.
Should I just do the job with what he supplied and keep my opinions to
myself?

Your call - seems daft to me though to do a job for a family member
that all falls off in 6 months.


NT

In article ,
william wrote:
I'm doing my first paid tiling job (for a family member) she got all
the material the supplier knew where the tile was to be fitted
(plastered drywall) he supplied a cement based powdered adhesive
It says on the bag "not to be used on gypsum based plaster" I asked
him about this and he said its fine to use it he has sold tons of the
stuff and never had a problem.

Hmm. It's normally much more expensive than the correct stuff - so perhaps
that accounts for him being so keen to sell it?

--
*OK, so what's the speed of dark? *

Dave Plowman London SW
To e-mail, change noise into sound.

On 5 Oct 2004 14:08:54 -0700, (william) wrote:

Hi
I'm looking for some opinions on using cement based adhesive on gypsum
plastered (skimmed) drywall?
I'm doing my first paid tiling job (for a family member) she got all
the material the supplier knew where the tile was to be fitted
(plastered drywall) he supplied a cement based powdered adhesive
It says on the bag "not to be used on gypsum based plaster" I asked
him about this and he said its fine to use it he has sold tons of the
stuff and never had a problem.
My sister in law (the client) is happy enough to use it she says he
should know what he is talking about, as it is his job.
To make things worse there is a shower that is to be tiled and the
substrate in the shower area is skimmed plasterboard (he says it is
perfect for this as it is a flexible adhesive).
I want to use ready mixed adhesive but am a bit unsure because the
walls are studded walls not solid block walls and they will move a
little.
The supplier thinks I'm a donkey and my client thinks I'm over
reacting.
But it says on the bag it's not suitable.
And I have researched it on the web and found something about some
reaction between cement and gypsum.
Should I just do the job with what he supplied and keep my opinions to
myself?

Hi,

Can you get the phone no. of the manufacturer from the bag or look it
up?

Or this might give an answer:

http://www.tiles.org.uk/help/answer-gypsum.shtml

more leads:

http://www.google.com/search?q=site%3A.uk+gypsum+plaster+tile+cement

cheers,
Pete.

In message , william
writes
Should I just do the job with what he supplied and keep my opinions to
myself?

I'm not an expert at tiling but I've found that if you first seal the
surface with PVA then use the pre-mixed Unibond combined grout/adhesive
from B&Q (and no doubt many other places) then the tiles will stick to
*anything*.

I've tiled on raw plaster, old tiles and wood without a single tile
coming loose. Good trick is to make sure you leave a gap at corners and
fill that with mastic so if your walls shift slightly it doesn't squeeze
the tiles off.

The odd thing is that when I buy tiles the tile shop always tries to
sell me powder adhesives. They say that the pre-mixed stuff isn't any
good as it "slumps". Never had any problems with it myself though.
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And I have researched it on the web and found something about some
reaction between cement and gypsum.

Nothing is going to work well if the plaster/plasterboard gets wet. There
are plenty of adhesives that will work on gypsum plaster, but if you get
water in behind the grout, the tiles will ping off and the plaster will
degrade.

I'd probably use something Like Ardu-Flex 6001 or BAL White Star, although
it would still be better to replace the plaster background with something
better.

If you don't replace the plasterboard with something waterproof, ensure you
do the tiling job thoroughly. Use an adhesive suitable for swimming pools
such as those mentioned above. Ensure complete coverage. This is not a time
for dab and dot, you need 100% fill between tile and plaster. Remove an
occasional tile during fitting to ensure that all ridges were compressed
flat.

Pay very careful attention to grouting. Use a flexible grout such as
ArduFlex FL/FS to reduce the chances of cracking. Keep the grout lines
narrow. Seal the grout using Lithofin StainStop (KF or MN, probably KF for
the types likely to be used in a shower). This will also stop the grout
going mouldy and will encourage water to bead and run off, rather than
penetrate the grout. You may wish to apply to the tiles as well as the grout
lines, depending on the level of glaze. Use silicone sealant for internal
corners of walls.

Christian.

"Christian McArdle" wrote in message et...
And I have researched it on the web and found something about some
reaction between cement and gypsum.

Nothing is going to work well if the plaster/plasterboard gets wet. There
are plenty of adhesives that will work on gypsum plaster, but if you get
water in behind the grout, the tiles will ping off and the plaster will
degrade.

I'd probably use something Like Ardu-Flex 6001 or BAL White Star, although
it would still be better to replace the plaster background with something
better.

If you don't replace the plasterboard with something waterproof, ensure you
do the tiling job thoroughly. Use an adhesive suitable for swimming pools
such as those mentioned above. Ensure complete coverage. This is not a time
for dab and dot, you need 100% fill between tile and plaster. Remove an
occasional tile during fitting to ensure that all ridges were compressed
flat.

Pay very careful attention to grouting. Use a flexible grout such as
ArduFlex FL/FS to reduce the chances of cracking. Keep the grout lines
narrow. Seal the grout using Lithofin StainStop (KF or MN, probably KF for
the types likely to be used in a shower). This will also stop the grout
going mouldy and will encourage water to bead and run off, rather than
penetrate the grout. You may wish to apply to the tiles as well as the grout
lines, depending on the level of glaze. Use silicone sealant for internal
corners of walls.

Christian.

I've been using white cement adhesive for kitchen and bathroom, and
they just fall off again. In fact when I cemented onto pva'd wood they
didnt stick at all, just lifted off when dry. Dont nkow what kind of
adhesive to choose, but obviously need something that works.


NT

I've been using white cement adhesive for kitchen and bathroom, and
they just fall off again. In fact when I cemented onto pva'd wood they
didnt stick at all, just lifted off when dry. Dont nkow what kind of
adhesive to choose, but obviously need something that works.

Ardicol D20 claims to stick to stable timber boards such as plywood.
Although intended for floor tiles, rather than wall, I'd be tempted to try
ArduFlex 7001 Timber System with Ardion 51 primer, although it doesn't claim
compatibility with walls...

Christian.

In article ,
N. Thornton wrote:
I've been using white cement adhesive for kitchen and bathroom, and
they just fall off again. In fact when I cemented onto pva'd wood they
didnt stick at all, just lifted off when dry. Dont nkow what kind of
adhesive to choose, but obviously need something that works.

I've used the white ready mixed stuff almost everywhere. Including a
shower cubical made of plasterboard. And the outside loo. Never had a tile
fall off yet.

--
*Who are these kids and why are they calling me Mom?

Dave Plowman London SW
To e-mail, change noise into sound.

"Christian McArdle" wrote in message et...
I've been using white cement adhesive for kitchen and bathroom, and
they just fall off again. In fact when I cemented onto pva'd wood they
didnt stick at all, just lifted off when dry. Dont nkow what kind of
adhesive to choose, but obviously need something that works.


did you tile kitchen and bathroom with adhesive from the same
bag/batch of adhesive?
if the bag is open and left around it seems to go off.
when it sets it just turns to dust(like sand).
on the bal website it says not to pva the surface of the plywood you
are going to tile just seal/prime the edges and back.

"Dave Plowman & christian McArdle replied...


thank you both, am going to investigate supplies.

NT