Hi I would be very grateful for your suggestions/thoughts.
Details:
-Laying ceramic floor tiles 33cm x 33cm in the conservatory - 15m sq..
-The floor was chipboard and I layed 12mm WPB plywood screwed at 25cm intervals.
-Coated with BAL - bond SBR
-Used homebases Evo-Stik Tile a Floor Adhesive (for Stone and Porcelain).

Steps so far:
I have made the adhesive as per instructions, I have nearly laid 3/4 of the floor!! Tiles are spaced 5mm apart using spacers. Adhesive was spread on using a floor notched trowel. I have only been able to lay around 4-8 tiles each evening due to work. After laying they have not been stood on or touhed for at least 24 hrs, despite packaging saying set within 2-3hrs.
Problem: I have started noticing line crackes appearing around the tiles. I popped a small trowel under one and it popped up. I am now going around all the tiles and most appear to not have stuck and sound hollow and their is movement. Some are just popping up when i apply a bit of force to the trowel. When lifted adhisve does not appear to have stuck well to floor!
I am not an experienced tiler, I have layed the kitchen floor tiles and their was no problem although this was much smaller, say half the size and I used homebases ready made adhesive.
My questions:
1. Ok so my main question is why is this doing it. My own stupidity? Product problem? - I am on my 3rd bag and the tiles appear unstable throughout the room which used all ahesives so i dont think so.
2. Could this product just be unsuitable for the area? The room does get very hot - would this cause the adhesive to dry out more than normal before grouting etc and cause it to crack?
3. Should i try an aleady made adhesive for wooden floors? Should I have gone with the more expensive BAL adhesive or some other products.
4. Should i rip them all up and try again?
I'm pretty peed off and disappointed. I had a really bad couple of weeks at work and now it look like I gotta do this again and time is a bit tuff to do this but cannot afford anyone to come in and do it. Plus i think this is someting i can do. Be very grateful for any help/suggestions.
Many thanks. Kevin

Kevin - My first thought would be to check the code/date on the adhesive and contact Evo stick to see if they have had any other batch problems! As I have never used Evo Stick I cannot comment on its suitability for your project. However I'am sure you checked that if was a fast set FEXIBLE adhesive suitable for tiling onto wood.
The plywood on top of chipboard is obviously going to have tremendous movement in a hot conservatory (they go + 100degrees) and with the weather of late you could be right with your assessment. However as you fixed the tiles in an evening the adhesive should not have been so affected.
When I used to use plywood it was always screwed at 150mm so your 250mm seems inadequate.
You don't mention what depth floor trowell you used or if you solid fixed the tiles to a minimum depth of 10mm.
Without being able to look at the tiles/adhesive I have to be vague in the response but my first thought is the way i would approach the problem and if unresolved I'd use a Mapei flexible adhesive.

Timeless John.

did you prime the surface and was it rapidflex ?

Many thanks for your responses. Much appreciated. I have decided to pull the tiles up and they are all up now. Will have to spend ages removing the adhsive from the floor and the tiles.
Timeless john -
I will look for the date/code and will follow up if necessary. Thanks. It says it was a fast det flexible suitbale for wooden floors. Confirmed by the Homebase sales assistant (although not relying on him too much).
Most tiles were fixed in the evening when it was cooler. The first lot were done during the day (around 20 tiles) when it was hot but they all appear to show the same problem, that is they have not bonded well to the floor.
Do you think that it is worth putting more screws in to reduce movement now tiles are up? This will make it 125mm apart then.
The trowel is a floor trowel form DIY. The notches measure 10mm height and 20mm width.
So depth should be ok at 10mm.
I have had a look at Mapei and it has good reviews. It appears cheaper (which is good for me, although i dont want to cut quality) than BAL single part flexible or bal rapidset flexible which I was considering. Have you had experience of BAL? Where would be the best place to get the mapei product.
PJC:
I used BAL SBR which is a bonding and primer. I was told this would be better than a PVA as any water can affect the PVA, not that there will be any.

GUEST!!..If you join up ( which is free) we can reply quicker as guests posts have to approved first..

most company's tell you to prime the back and edges not the face

Ok just registered, thanks.

I only primed top and sides, not underneath. As this was a bonding agent as well I was told to do top of tiles and not underneath.

floating floor perhaps ?

The subfloor i think is joists with the chipboard over it. It looks at least 18mm. It appeared to be screwed at regular intervals. There did not appear to be any movement and therfore dont think it is a floating floor?

Did you trowel the adhesive directly onto the floor and then backskim the tiles before fixing? Or just back butter the tiles before fixing?

I did alittle research on the Evo Stik Tile a Floor - Stone and Porcelain and couldn't really find much information. It says it's suitable for wooden floors but it's not very specific. I.E, most adhesives will say use 15mm ply etc. But this one just says "suitable for wooden" floors

Thanks again for your replies.

Captian slow:
I just applied the adhesive to the flow and used the notched trowel at 45 degrees, laid the tiles down with a little pressure ensuring it was flat with spirit level at times.


Matt 257:
Thanks for taking time out to check this out. I checked out their website and there was not much just said ok for ceramic and wooden floors.

I think I will be looking into the mapei adhesive as timeless john suggested or perhaps the BAL adhesive products. Just rather frustrating that tiles were nearly all laid. However, I guess it is better than to have grouted and then couple of weeks later have it come up. Lessen may be to not try and cut corners with cheaper materials (adhesives) to save a couple of quid. It has now cost me £75 as I have ripped all the tiles up. But anyway you learn from your mistakes. Not completely blaming the adhesive as there have been some good reviews. But something has clearly gone wrong.

Regards. Kevin

If you decide to go for Mapei adhesive and have a Tile Giant close to you. Pop in and mention the Tilers Forum, they will look after you

Before you start relaying, I would make sure your substrate is sound, because if it wasn't a problem with the adhesive, the chances are the same thing may happen.

Thanks Matt257. There is a tile giant near by which I was going to pop down later
I think I will place a few more screws in but I thought 250mm gaps should have been sufficient. There doesnt appear to be any movement

Is it ok that I applied BAL SBR to top surface and sides. I'm now reading in more posts that it should be underside and sides? The reason why i placed in on top is that I thought the adhesive can draw moisture from the ply and it also acts as a bonding agent!

Just need to finish up clearing old adhesive off floor and tiles. Half way through. Did i need to apply another primer/bonding agent as there is now a thin layer/coating of adhesive on the surface of the wood or can the new adhsive go straight on top?

Cheers

Just a quick question when your popping the adhesive up does it look like it has stuck more to the floor or to the tiles or is it pretty much equal. This may help diagnose the problem.

As it looks like it could be failed adhesive I would try and get it all off imo.

if there is a coating of adhesive still on the floor it must be movement or skinning more likely movement :Pete

Agree with above poster sounds like the adhesive is skinning over before you lay maybe mixed to little water or waiting to long before laying tiles you have to remember adhesive skins over double quick in hot weather . also i personally think evo-stick is absolute pony steer toward mapei/bal.

it is mixed some on tiles and some floor. Have removed as much as possible but still adhesive residue left.
I think that maybe the adhesive was left too long to apply at times and it was very hot in the room. This is probably one of the main contributory factors now i thins. Anyway once i get some of that Mapei adhesive i will ensure that i either get slow drying or get it down quick in the evenings when it is cooler.

Originally Posted by kevb

it is mixed some on tiles and some floor. Have removed as much as possible but still adhesive residue left.
I think that maybe the adhesive was left too long to apply at times and it was very hot in the room. This is probably one of the main contributory factors now i thins. Anyway once i get some of that Mapei adhesive i will ensure that i either get slow drying or get it down quick in the evenings when it is cooler.

Which is your closest Tile Giant?

There is one in sittingbourne which is in the south east of kent. it is only a couple of miles from me but i am still removing old adhesive and dont think i will get it removed by 4pm when they close. Regards.

Originally Posted by kevb

There is one in sittingbourne which is in the south east of kent. it is only a couple of miles from me but i am still removing old adhesive and dont think i will get it removed by 4pm when they close. Regards.

Thanks. I just wanted to check what they had in stock before you made the trip. They have Keraflex Maxi (White and Grey) in stock. Keraflex Maxi is a flexi adhesive that will do what you need to. It also has an 8 hour pot life and open time of about 30 mins which will help a great deal in this weather. Good luck with the job

Thanks matt257

You have to use rapid set on timber not slow set:Pete

Originally Posted by pjc

You have to use rapid set on timber not slow set:Pete

Keraflex Maxi is suitable for Ply

Why would you need to use Rapid Set?

Originally Posted by matt257

Keraflex Maxi is suitable for Ply

Why would you need to use Rapid Set?

moisture content and the way it sets

Originally Posted by pjc

moisture content and the way it sets

Not heard that before, thanks. I always thought that because a cement based addy doesn't use dispersion to set, that even slow set would be ok for wood. So is no slow set ok for wood even though Mapei say Keraflex Maxi is?

I would be looking at that floor first, It sounds suspect to me, go over it with a fine toothcomb and make sure their is no bounce at all, you must use the correct addy, do you know a tiler that could give you some info by looking at it for you, you have wasted money already on addy already, if your definately not getting a pro in to do it then a few quid as a tip for a bit of knowledge seems a small price to pay to get you on your way ( i'm a poet )

Bal flex is not rapid setting adhesive and is absolutly fine for timber floors though it is recommended that a primer is NOT used prior to fixing, if you want a faster set then bal rapid flex is the way to go but it does not have to be rapid setting for timber floors just flexi.

But if you can see the floor flexing when you press on the trowel then you have a deflection problem with the boarding which will need sorting first.