Tiles falling off tanking - why!!!

[Gixerguy]

Hi again - I have yet another problem I'm hoping you can solve for me!

I've applied Homelux membrane tanking to the two walls of my corner shower. It's on the right way ie correct side to the wall. The walls are brick & plaster (finish coat) and I used Granfix CFTA powder addy. It seems to have stuck like @@@ to a blanket lol

However, two days later I applied a few tiles (ceramic 20x10 8mm) using the same addy. Where the tiles are on the wall they're fine but after 24hrs the tiles on the tanking will fall off with a little nudge and the addy is wet still - you can literally wipe it off. The room is suitably warm and dry.

Homelux say that Im doing it all right and that Granfix is fine for this use.

I don't understand whats gone wrong!

As always I really appreciate your help and advice,
Many thanks guys!

Darren

 

[doug boardley]

I'm baffled by that mate, are the back of your tiles dust free?

 

[Gixerguy]

Hi Doug, the tiles are clean i wipe each one with a sponge that is very very slightly damp it barely changes colour of the tile but gets the dust off. It seems that the edge of the addy dries but the rest cant lose the moisture? But with powder i thought the bond was chemical not water loss?

Im no pro but cant see any obvious cause!!

 

[doug boardley]

any chance it was a duff batch of adhesive?

 

[Gixerguy]

Im thinking it's prob not as the addy has stuck to the walls perfectly - the only variable is the tanking - just noticed that once the tile is off the addy dries in about 1hr and sets fine so it seems that the tanking stops the moisture leaving ??

 

[doug boardley]

I'm at a loss then mate, what tiles are you using, ceramic, porcelain, glass?

 

[Deleted member 9966]

Did you prime the tanking membrane before tiling on to it?

 

[Gixerguy]

The tiles are ceramic,

I didnt prime the membrane - Homelux dont advise this.

I have tried a sample area with BAL SPF - might have to wait 'til tomorrow to see if it bonds. I WILL post and let you know.

Thanks for your replies all!!

 

[Gazzer]

Did you prime the tanking membrane before tiling on to it?

You dont need to prime the tanking after.

 

[jay]

is it granfix CFTA STANDARD ADH that you used

 

[Gazzer]

is it granfix CFTA STANDARD ADH that you used

Its a SPF

 

[jay]

yes but is it self setting:8:

 

[Diamond Pool Finishers]

mix a test patch up and leave over night ,from the same addy ,on a bit of board ??

 

[jay]

okay read data sheet and it seems to take 24 hours to set normally on porous surfaces tile and substrate so if you have tile and membrane it may struggle as this type of adh dries by absorption of moisture by tile and substrate there for it will stick to tile but might not to membrane unless left for a long time 48 hours plus doesn't mention membranes in data sheet at all/////////:8:


self setting adh set without the need of porous substrate or tile

 

[Gixerguy]

Thanks for your replies - heres an update lol
After many calls between Homelux & Granfix I'm being told it is quite likely that the addy I used isnt suitable for this tanking.
Homelux had originally said it qould be fine when I was researching the project but in light of my difficulties have looked deeper and suspect that it differs slightly from BAL SPF which is the preferred addy.
The tanking has also not bonded but come off clean leaving ALL the addy wet on the wall.
Homelux have been BRILLIANT and not only given advice throughout but are replacing my tanking & joint tape FREE OF CHARGE by next day delivery (tomorrow) and I even have a Homelux Tech Advisors personal number to update in the morning as to whether the SPF test works.
So although I'm just a joe public they're looking after me very well!!!!!!!
It does seem that as good as the Granfix addy is something upsets it when used in these circumstances. As promised i will update tomorrow so we can all learn from this lol
Thanks again all
Darren

 

[doug boardley]

I look forward to the update Darren

 

[White Room]

Back skim the tiles aswell

 

[tommyzooom]

Nice to see a bit of good customer service
Well done Homelux

 

[CJ]

Interesting reading.

Hope it works out for you Gixer

 

[mikethetile]

thanks for posting this gixer

clearly theres a problem and you have done the field testing for them

hope it works out for you , its frustrating when things go wrong

 

[Gixerguy]

Morning all!

It's been one step forwards and half back im afraid.......

The SPF test tiles had partly bonded to the membrane - on removal some matting was attached to the tiles but there was still a considerable area yet to bond. To be fair it's approx 18-20 hrs since app so that seems within my amateur expectations ...... HOWEVER......

The test tile on the wall (primed with 2 neat coats of Granfix acrylic primer as per MI) came off with modest effort with equal spread of addy tile to wall but no sign of bonding?????

During the removal of the tanking I found NO addy on the tanking - it was ALL on the wall and still wet in most areas. I have scraped it all off with spray water to soften harder areas. It came off with no damage to the finish coat plaster. While using the water I noticed the wall absorb the water readily - as if no primer was there. Yet when i spray onto a primed wall else where the water runs down the wall as if with so little absorbed that it just leaves 'egg shell' discolouration - is this normal or have i (on Granfixs' advice) overdone the primer and sealed the wall thus preventing the addy disposing of its water whilst bonding?

Im learning all the time so if I have some odd ideas forgive me lol lol

Thanks again!

Darren

 

[jay]

hi not familiar with that adh and it seems to be the basic adh have a talk to homelux and see which adh they can recommend to use with there product:8:

some adh are not compatible with membranes especially tubbed adh (i do not recommend using tubed adh on membranes)

 

[clive matthews]

hi not wanting get of beaten track but is your water pure, when i used to do site work i have seen a bloke washout brick cleaning acid in the water butts bricklayers sometimes plastisizer up the whole butt etc then everyone else dives in pulling out buckets of infected water without knowing

 

[Gixerguy]

Thanks Clive, its just tap water Im using so it's clean (well...... Lol )

Could someone advise me as to whether I should prime the walls before applying the tanking? Im using BAL SPF and Homelux membrane on finish coated plaster over brick to save you reading my stories again lol

I have spent the day sanding off the Granfix adh and primer that failed so I've got fairly fresh walls again and now need a few beers lol

Cheers all!

 

[doug boardley]

yes, mate prime the plastered walls before fiixng membrane

 

[Sutwam]

Hi Gixer, I have this tech sheet for a Dural Wp matting, but all these mattings fix in a similar way so I thought it might be worth you seeing it. Good luck with it!


WP Membrane


Technical advice on installation.

The benefit of WP membrane is that it is waterproof

The problem is that the WP membrane is waterproof,

This prohibits the curing or setting of dispersion type adhesives normally used to fix wall tiles.

Dispersion adhesives are ready mixed that come in buckets ready to apply. When used with tiles the water in the adhesive “disperses” into the biscuit of the tile and into the absorbent substrate such as plaster or plaster board. The adhesive then dries hard.

When the WP matting is used this dispersion cannot happen as quickly as the water cannot escape through the membrane and must only go into the substrate, eventually being absorbed.

The net effect is a slow bond between the WP and the wall substrate.

This is governed by the rate of absorption of the moisture from the adhesive

The trowel used to apply this initial bond layer has small serrations of 3 – 4mm. This reduces the amount of adhesive and therefore moisture behind the WP membrane.

As soon as a good bond is achieved, the tiling onto the surface can take place. With dispersion adhesive the only place the water can go is into the tile biscuit or escape through the grout lines. The adhesive at the edges of the tiles sets hard forming a perimeter ring around the edges of the tiles. The adhesive in the middle can remain un-set and liquid. This can be viewed as a “picture frame” effect. This is not a good thing for safety.

The use of Porcelain tiles, which absorb little or no water, means that the adhesive will never actually set!

For these reasons we recommend that a hydraulic type adhesive is used, (commonly known as Bag or Powder adhesives, this type of adhesive sets chemically with the addition of water and will even set under water). However this raises another difficulty. Most wall substrates in domestic housing are covered with Gypsum plaster. The cement in hydraulic adhesive reacts with plaster and a substance called Ettringite is created. This substance gains in volume as it is created and causes pressure in the same way that freezing water becomes ice and cracks pipes. This volume change can cause WP membrane to debond.

Therefore it is vital that any plaster surfaces must be suitably protected by priming or that a special adhesives that will not react to the plaster is used for this initial bond.

The use of hydraulic adhesive to bond tiles to the surface of WP is more successful. Even with the waterproof nature of the WP membrane the adhesive will always set and harden. This is also the case with porcelain tiles.

In summary the water proof nature of the WP membrane makes the use of dispersion adhesives difficult, unreliable and slow. Success will be achieved by using the right hydraulic powder adhesive with care taken to ensure any necessary priming has been completed on the substrate.

Key points

• Use a fine notched trowel on the initial coat.
• Prime or use a special adhesive to allow tiling onto Plaster.
• Use hydraulic adhesive.

​

 

[JFRWhipple]

This is an interesting thread - for sure.

Here in Vancouver I have discussed waterproofing techniques with my local Schulter and Custom Building Products reps on many occasions.

I have read a ton of information over the years, tested my product choices on many projects with great success over the past 7 years.

The simplest fail safe test on them all is the "Idiot Test" this test can track down a whole list of unseen problems.

Set a sample board with your waterproofing and setting materials. These board is key for insuring you have the right materials and grout. Clients can see dried grout colours and tile spacing first hand. This board can be used for layout and given to the plumbers for working out tile thickness etc.

Ready mixed thinsets (mastic, glue, etc) as mentioned in the post above needs the moisture to escape to have the product set. Most of our Porclean tile, ceramics, glass and stone let little if any moisture escape. The other down side is that mold can feed of this product as well as I'm told.

In the shower renovation mentioned above we would have used a non modified thin set to set the tile over the waterproofing. Mastic (glue) we use for kitchen back splashes on rare occasions and we try not to work with any ready made product as a rule.

With a larger format tile there is a good chance that the mastic product never cures behind the tile - also the fact that mould can feed on this type of product is unsettling for me. perhaps these products have been designed differently in your neighborhoods but here in NA I stay well clear of "mastic"

My thoughts...

 

[DHTiling]

Just to add john..

Schluter.com and Schluter.uk have different recommends for tiling to schluter membranes..

In the USA Schluter.com say to use a none modified thinset and here in the uk Schluter.uk say it is fine to use a modified adhesive..

So in theory we have seperate methods when using Schluter membranes.

Strange hey!!

 

[JFRWhipple]

Very Strange.

I believe that the additive in the modified thinset is semi waterproof. If water can't get out with ease it really isn't setting up.

With Non Modified thinset the moisture can migrate through the thinset and evaporate along the grout lines.

I have been using non modified thinset on all my jobs with waterproofing for the past 7 years - Zero call backs.

I think I should call my reps and review one more time - especially this difference between the use of non modified thinsets. There has to be more to the equation...

 

[Dan]

Just bumping some of the older popular (sometimes not so popular) threads. Probably wont be current discussion these days but I just need to do it. So just ignore the thread if it's not current for you.