Apparently something of a no no, but has anyone tiled onto MDF
successfully?

It's a window reveal in a kitchen. Old tiles detached, hardly any
old adhesive stuck to the MDF underneath.

Wondering what to use to stick them back?

TIA
--
Jim K


----Android NewsGroup Reader----
http://usenet.sinaapp.com/

Seal the MDF first, PVA will do.

Richard

On 04/02/2019 12:10, Jim K.. wrote:
Apparently something of a no no, but has anyone tiled onto MDF
successfully?

It's a window reveal in a kitchen. Old tiles detached, hardly any
old adhesive stuck to the MDF underneath.

Wondering what to use to stick them back?

Not MDF but I've had a problem with the floor tiles I laid onto green
chipboard.

Originally we were simply going to extend the wood flooring into the new
extension then, like they do, the good lady changed her mind and wanted
tiles.
To cut a long story short I'm still waiting for any remaining tiles to
loosen. The ones that parted company so far have all been over the end
joins of the chip board.

Needless to say my favourite anything-to-anything building adhesive has
been used to re-attach the tiles to the floor.
Gun Grade expanding foam!

Where possible I left securely fixed tile adhesive on parts of the tile
to give correct height alignment with adjacent tiles. Sanded top surface
of chipboard to remove any waxes etc., mist chipboard and tile underside
with water, apply foam to back of tile and position. Add a few weighty
weights that overlap to surrounding tiles to ensure the foam doesn't
have chance to expand and lift tile and leave long enough for foam to
fully cure.

Still haven't grouted the tiled floor yet but the tiles that have been
re-fixed with foam are very solid and the one I did try and re-lift
wasn't coming up without breaking so I left it alone.

You might want to hold the tiles in position with a bit of flat timber
braced from opposite reveal or allow foam to fizz out a little before
applying tile to MDF as this seems to break the external skin of the
curing foam leaving a very tacky residue that seems to have very little
ability to expand any further and can be held in position by hand for 5
minutes or so until foam has stabilised

Damping both surfaces before applying foam ensures a quick and full cure
of foam.

Sounds like a bodge but I can't immagine anything else working as well
or being as easy/quick/economical to apply.
Gun and gun foam are invaluable. The foam doesn't go off in the gun
either unlike stuff like Gorilla Glue that you use once and what's left
inevitably cures in the pot.

Pete
--
http://www.GymRatZ.co.uk

On Monday, 4 February 2019 12:54:33 UTC, Tricky Dicky wrote:
Seal the MDF first, PVA will do.

Richard

With respect, PVA should never be used as a sealant before tiling. If it gets wet it will fail. Use something like Mapei Primer G which isn't expensive.

https://www.toolstation.com/mapei-plaster-primer/p57804

Kevin H Wrote in message:
On Monday, 4 February 2019 12:54:33 UTC, Tricky Dicky wrote:
Seal the MDF first, PVA will do.

Richard

With respect, PVA should never be used as a sealant before tiling. If it gets wet it will fail. Use something like Mapei Primer G which isn't expensive.

https://www.toolstation.com/mapei-plaster-primer/p57804


Primer G instructions refer to use on gypsum & similar surfaces,
this is MDF?

I think I'm going to use MS polymer adhesive.
--
Jim K


----Android NewsGroup Reader----
http://usenet.sinaapp.com/

On Monday, 4 February 2019 14:38:20 UTC, JimK wrote:


Primer G instructions refer to use on gypsum & similar surfaces,
this is MDF?

I think I'm going to use MS polymer adhesive.
--
Jim K

Would it be possible to overboard with something like 6mm cement board (hardibacker or similar)? If the MDF is mechanically well fixed into the window reveal then the cement board will give a much better surface for tiles to adhere onto.

If there is any risk that this area will get wet then getting rid of the MDF and replacing with WBP or 15/18mm cement board would be what I'd be doing. Also, use a cement based powdered adhesive - stay away from the stuff you get in tubs.

Oh please don't remind me...
A wall, not mdf but block and plastered but not any kind of fixing at the
top. Electricians rewire hose used power tools to cut out room for socket
back box in next room, tiles fell of in bathroom due to wall motion.
Bah humbug.
We just cleaned off loose stuff checked for more loose ones and glued them
back and regrouted. Been OK so far!
Brian
Brian

--
----- --
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please
Note this Signature is meaningless.!
"Jim K.." wrote in message
o.uk...
Apparently something of a no no, but has anyone tiled onto MDF
successfully?

It's a window reveal in a kitchen. Old tiles detached, hardly any
old adhesive stuck to the MDF underneath.

Wondering what to use to stick them back?

TIA
--
Jim K


----Android NewsGroup Reader----
http://usenet.sinaapp.com/

On Monday, 4 February 2019 13:01:35 UTC, www.GymRatZ.co.uk wrote:
On 04/02/2019 12:10, Jim K.. wrote:

Apparently something of a no no, but has anyone tiled onto MDF
successfully?

It's a window reveal in a kitchen. Old tiles detached, hardly any
old adhesive stuck to the MDF underneath.

Wondering what to use to stick them back?

Not MDF but I've had a problem with the floor tiles I laid onto green
chipboard.

Originally we were simply going to extend the wood flooring into the new
extension then, like they do, the good lady changed her mind and wanted
tiles.
To cut a long story short I'm still waiting for any remaining tiles to
loosen. The ones that parted company so far have all been over the end
joins of the chip board.

Needless to say my favourite anything-to-anything building adhesive has
been used to re-attach the tiles to the floor.
Gun Grade expanding foam!

Where possible I left securely fixed tile adhesive on parts of the tile
to give correct height alignment with adjacent tiles. Sanded top surface
of chipboard to remove any waxes etc., mist chipboard and tile underside
with water, apply foam to back of tile and position. Add a few weighty
weights that overlap to surrounding tiles to ensure the foam doesn't
have chance to expand and lift tile and leave long enough for foam to
fully cure.

Still haven't grouted the tiled floor yet but the tiles that have been
re-fixed with foam are very solid and the one I did try and re-lift
wasn't coming up without breaking so I left it alone.

You might want to hold the tiles in position with a bit of flat timber
braced from opposite reveal or allow foam to fizz out a little before
applying tile to MDF as this seems to break the external skin of the
curing foam leaving a very tacky residue that seems to have very little
ability to expand any further and can be held in position by hand for 5
minutes or so until foam has stabilised

Damping both surfaces before applying foam ensures a quick and full cure
of foam.

Sounds like a bodge but I can't immagine anything else working as well
or being as easy/quick/economical to apply.
Gun and gun foam are invaluable. The foam doesn't go off in the gun
either unlike stuff like Gorilla Glue that you use once and what's left
inevitably cures in the pot.

Pete

Expanding foam is about the worse stuff one could use for floor tiles. If there's one thing such tiles must have it's rock solid support all over - far more solid than any foam could possibly give.

Tiles on MDF, chipboard etc are also bodge jobs. You can do it but don't expect it to last well.

Next someone will be suggesting silicone as floor tile adhesive! I've got the results of that, thanks to some previous bodger.


NT

On 04/02/2019 12:54, Tricky Dicky wrote:
Seal the MDF first, PVA will do.

Richard

Dont ****ing bother. It merely makes the tiles more liable to fall off
when half set.



--
"What do you think about Gay Marriage?"
"I don't."
"Don't what?"
"Think about Gay Marriage."

On 04/02/2019 13:01, www.GymRatZ.co.uk wrote:
On 04/02/2019 12:10, Jim K.. wrote:
Apparently something of a no no, but has anyone tiled onto MDF
successfully?

It's a window reveal in a kitchen. Old tiles detached, hardly any
old adhesive stuck to the MDF underneath.

Wondering what to use to stick them back?

Not MDF but I've had a problem with the floor tiles I laid onto green
chipboard.

Originally we were simply going to extend the wood flooring into the new
extension then, like they do, the good lady changed her mind and wanted
tiles.
To cut a long story short I'm still waiting for any remaining tiles to
loosen. The ones that parted company so far have all been over the end
joins of the chip board.

Needless to say my favourite anything-to-anything building adhesive has
been used to re-attach the tiles to the floor.
Gun Grade expanding foam!

Where possible I left securely fixed tile adhesive on parts of the tile
to give correct height alignment with adjacent tiles. Sanded top surface
of chipboard to remove any waxes etc., mist chipboard and tile underside
with water, apply foam to back of tile and position. Add a few weighty
weights that overlap to surrounding tiles to ensure the foam doesn't
have chance to expand and lift tile and leave long enough for foam to
fully cure.

Still haven't grouted the tiled floor yet but the tiles that have been
re-fixed with foam are very solid and the one I did try and re-lift
wasn't coming up without breaking so I left it alone.
#

This is all about flexure.

I had similar and retiled using a thick (5mm) bed of FLEXIBLE adhesive.
No more issues.






--
"What do you think about Gay Marriage?"
"I don't."
"Don't what?"
"Think about Gay Marriage."

Kevin H Wrote in message:
On Monday, 4 February 2019 14:38:20 UTC, JimK wrote:


Primer G instructions refer to use on gypsum & similar surfaces,
this is MDF?

I think I'm going to use MS polymer adhesive.
--
Jim K

Would it be possible to overboard with something like 6mm cement board (hardibacker or similar)? If the MDF is mechanically well fixed into the window reveal then the cement board will give a much better surface for tiles to adhere onto.


Not without it turning into a major retile...

If there is any risk that this area will get wet then getting rid of the MDF and replacing with WBP or 15/18mm cement board would be what I'd be doing. Also, use a cement based powdered adhesive - stay away from the stuff you get in tubs.

Mmmm

I was surprised how dry & intact it all was when I peeled the
tiles off (with 99.9% of the adhesive stuck to their
backs).
I've ground all that off the tiles ready for refitting.

Seems MDF & traditional "tile adhesives" are incompatible, so I
think I'll put my money on MS polymer adhesive a la "sticks like
sh1t", then grout traditionally, & put a decent silicone fillet
around any edges (e.g. pvc window frame) to try to keep potential
damp (steam, condensation etc) creeping in.

--
Jim K


----Android NewsGroup Reader----
http://usenet.sinaapp.com/

Glued with what?


"Brian Gaff" Wrote in message:
Oh please don't remind me...
A wall, not mdf but block and plastered but not any kind of fixing at the
top. Electricians rewire hose used power tools to cut out room for socket
back box in next room, tiles fell of in bathroom due to wall motion.
Bah humbug.
We just cleaned off loose stuff checked for more loose ones and glued them
back and regrouted. Been OK so far!
Brian
Brian



--
Jim K


----Android NewsGroup Reader----
http://usenet.sinaapp.com/

On 04/02/2019 15:57, wrote:

Expanding foam is about the worse stuff one could use for floor tiles. If there's one thing such tiles must have it's rock solid support all over - far more solid than any foam could possibly give.


They do have a solid support. As much as any "over joist" construction
can give.
They're not floating on foam, they're spaced on the original adhesive
"ridges" with foam run between the gaps as created with the notched
adhesive trowel when initially laid. The so called "flexible" tile
adhesive I originally used has zero "flex" and the same amount on
non-adhesion not just to the floor but to the tile surface too.

I put the tiles down quite a few months ago now but have been holding
off grouting to make sure no more tiles are going to detatch themselves.
Once the the grout is squeezed into any gaps they'll be as solid as
they ever could be.

I don't envisage any problems the the re-attached tiles. Perhaps
hairline cracks /might/ appear in some of the grout lines but that
doesn't really worry me, they're all underfloor heated and the
underlying chipboard is waterproof/resistant anyway so all will be fine.

Using foam to re-adhere them was an act of desperation in preference to
scrapping the floor tiles which surpassed any expectations by a massive
amount. They're pretty much on a micro-thin layer of polyurethane
adhesive (foam without bubbles)which is proving to be an almost
molecular bond between surfaces not some ishy-squishy "foam" that moves
about.

On 04/02/2019 18:23, www.GymRatZ.co.uk wrote:
On 04/02/2019 15:57, wrote:

Expanding foam is about the worse stuff one could use for floor tiles. If there's one thing such tiles must have it's rock solid support all over - far more solid than any foam could possibly give.



********. google 'flexible tile cement'

like a hard rubber when set


They do have a solid support. As much as any "over joist" construction
can give.
They're not floating on foam, they're spaced on the original adhesive
"ridges" with foam run between the gaps as created with the notched
adhesive trowel when initially laid. The so called "flexible" tile
adhesive I originally used has zero "flex" and the same amount on
non-adhesion not just to the floor but to the tile surface too.

I put the tiles down quite a few months ago now but have been holding
off grouting to make sure no more tiles are going to detatch themselves.
Once the the grout is squeezed into any gaps they'll be as solid as
they ever could be.

I don't envisage any problems the the re-attached tiles. Perhaps
hairline cracks /might/ appear in some of the grout lines but that
doesn't really worry me, they're all underfloor heated and the
underlying chipboard is waterproof/resistant anyway so all will be fine.

Using foam to re-adhere them was an act of desperation in preference to
scrapping the floor tiles which surpassed any expectations by a massive
amount. They're pretty much on a micro-thin layer of polyurethane
adhesive (foam without bubbles)which is proving to be an almost
molecular bond between surfaces not some ishy-squishy "foam" that moves
about.


may work, but I think you need 'thickness' and flexible thickness at that.




--
€œThose who can make you believe absurdities, can make you commit
atrocities.€�

€• Voltaire, Questions sur les Miracles Ã* M. Claparede, Professeur de
Théologie Ã* Genève, par un Proposant: Ou Extrait de Diverses Lettres de
M. de Voltaire

On Monday, 4 February 2019 18:35:48 UTC, The Natural Philosopher wrote:
On 04/02/2019 18:23, www.GymRatZ.co.uk wrote:
On 04/02/2019 15:57, tabbypurr wrote:

Expanding foam is about the worse stuff one could use for floor tiles. If there's one thing such tiles must have it's rock solid support all over - far more solid than any foam could possibly give.



********. google 'flexible tile cement'

like a hard rubber when set

google 'bodge'


NT