Help!: Is this a bad install?

[Indy]

Hi,
Around six months ago I managed to find me a tiler from these forums and he tiled the entire ground floor of my house. The job was done as follows with his recommendations -

18mm Marine ply screwed down at 150mm centres with a 5-7mm gap between the plys filled with a flexible silicone
Ardex AF200 laid down with a 6mm trowel
Ditra Mat on top of that
Nicobond S1 Rapidflex tile adhesive
600x600mm and 400x200mm porcelain tiles used.
Nicobond Flexible Grout Plus

I've recently noticed that the odd tile has a bit of bounce in it as it's not stuck down firmly, one of my kitchen tiles is sinking and the grout in general has started to crack in my rear extension kitchen.

Here are a few photo's of that dodgy kitchen tile







This is driving me bonkers as to why it could be happening

I didn't turn the UFH in one go, I turned up the thermo 1C per day until I got to 25C.

It was snowing at the time and the house had no heating, could the install temp be a problem? I raised this with my tiler at the time but he said it wasn't an issue.

Any ideas gents, your help would be much appreciated.

Thanks
Indy

[Sir Ramic]

Can you confirm the colour of the Ditra mat, just in case it wasnt in fact Ditra !

[andy allen]

was the ply screwed down onto chip board....and is it a floating floor.

[Dave]

Looks like a deflection issue.. Is the floor onto joists.?

[Indy]

Yes it is a floating floor gents. I used 9x2 joists and the ply was screwed directly down onto them. I over did it on the brick pillar supports plus I used 4x4 timbers to support the joists where it wasn't possible to use joist hangers. I over did it on the noggins as well, overall it was all strapped up really well.

The floating floor consisted of 4" Kingspan with the UFH pipes sitting on top of them.

The Ditra Mate was bought from Tile HQ, definetly a bonafide company (well I hope so) so I don't think it's knock off far eastern stuff. It's jaffa orange in colour with hollow squares on one side and a carpet/felt type material on the other.

[andy-p]

I think the floating floor could be the problem ..

[Dave]

If the substrate is on joists then it is a suspended floor and not floating,as in chipboard just sat on kingspan with no fixings..

You will need to lift one of those tiles to see what has happened underneath.. but a call to your tiler is needed as well.

[Sir Ramic]

A couple of things here apart from what Dave has said. Am I understanding that it is 2 different substrates ? one floating and one suspended ? is the problem where the 2 meet ?

Now to the ply ! was it quality ply? I say this because the price of ply varies so much with the cheaper stuff being far too inferior IMO to be used for a base for any form of floor tiling.

[Indy]

Thanks for your advice gents.

Just to clear up the floor..it's a suspended floor then.

A few pics from the install

Lounge floor


Gaps between ply


A section of the kitchen floor


Kitchen floor


The entire ground floor is a suspended floor. I had brick pillars made up to support the joists. I don't have any problems with tiles at the junction of rooms where they meet, the problems are in different places; some in the middle of say the lounge and in the case of the kitchen a few feet from a wall - completely random.

I own a builders merchant so I used top quality ply and didn't skimp in this area, it was mighty tempting but I resisted the lure of money savings in order for a better job.

So is it a case of getting my Stanley knife out and cutting away at some grout in order to pull a tile up? I guess it's the only way if I'm going to find out what is happening underneath .

I'm not in a position to call the tiler back, he made a complete hash of my bathroom mosaics and bathroom in general so I doubt I'll be seeing him again.

[pjc]

if there was no heating on was the ply sealed on the back and edges and what with did it take in the moisture and now it has dried out and srunk

[Colour Republic]

How deep are are the notch out for the UFH pipes?

[Indy]

How deep are are the notch out for the UFH pipes?

Between 20 and 25mm would be a good guess.

if there was no heating on was the ply sealed on the back and edges and what with did it take in the moisture and now it has dried out and srunk

I didn't consider this TBH.

I spent a fair bit of time inspecting every tile in the kitchen and it seem that on most tiles you can press down in one corner and the tile moves down a 1mm or 2. It's as if there is some vertical give of at least a few mm, is this normal lads?

[Sir Ramic]

You really need to remove a tile and see if that throws up any more info. While you may have fell out with your tiler he still should have some responsibility "If" he is at fault...tricky situation.

[Indy]

You really need to remove a tile and see if that throws up any more info. While you may have fell out with your tiler he still should have some responsibility "If" he is at fault...tricky situation.

Yeah you're right, I'll pick up one of these grout rakes and get a tile removed. I'll post some pics when I'm done. This feels like CSI but for tilers lol.

[whitebeam]

No thats not the norm to have any movement/bounce in the tile.

[Indy]

but, but all of my tiles bounce, and no the guy that installed them wasn't called Tigger.

Oh WORD REMOVED, erm excuse whilst I go and cry in the cellar.

[kilty55]

can you lift a tile indy and post what it looks like underneath this may help

[andy tiler]

yes deffo need more pics, was there any bounce in the plywood floor before it was tiled.this could b a number of things, i think u need to call the (tiler) bak aswell...!

[jay]

but, but all of my tiles bounce, and no the guy that installed them wasn't called Tigger.

Oh WORD REMOVED, erm excuse whilst I go and cry in the cellar.

any wine down there might be another option

[Ken Bruty]

Where the joints in the boards are, are there noggings underneath or do the boards have no support underneath the joins? Could be your problem if not as the boards will flex at those joins.

[CJ]

Was the joists and ply acclimatised to the house...............U mentioned that there was no heating on in the house. How cold was the house when laid

[mredd]

From a plumbers point of view, max depth for a notch in a 9inc joist is 22.86mm (1/8 joist depth). They look like at least 35mm if the pipe is approx 15mm. There should be at least 6 inc gap between the notches. (3x joist thickness.There looks like 4inc ) Floor & Roof joist notches
There are also distances from the brick supports (see link).
This might be part of the problem.

[Sir Ramic]

From a plumbers point of view, max depth for a notch in a 9inc joist is 22.86mm (1/8 joist depth). They look like at least 35mm if the pipe is approx 15mm. There should be at least 6 inc gap between the notches. (3x joist thickness.There looks like 4inc ) Floor & Roof joist notches
There are also distances from the brick supports (see link).
This might be part of the problem.

So basically ...Deflection !

When a tile is removed you will then be able to see if the sub floor is showing signs of movement. Then if thats the case you need to sort out why ?

[Indy]

yes deffo need more pics, was there any bounce in the plywood floor before it was tiled.this could b a number of things, i think u need to call the (tiler) bak aswell...!

Definitely no bounce after the floor was laid, the whole thing felt really nice and solid.

Where the joints in the boards are, are there noggings underneath or do the boards have no support underneath the joins? Could be your problem if not as the boards will flex at those joins.

There was only space for me to put some 2x1 noggins (on top of the insulation boards). This was an afterthought as I read upon this way too late but once I had screwed them in nice and tight between the joists, they were nice and solid and could easily take my weight standing on upon them. I didn't leave any edges of plyboards just hanging and not sitting on anything, anyway I had to screw the plys down so the extra noggins were definitely needed.

Was the joists and ply acclimatised to the house...............U mentioned that there was no heating on in the house. How cold was the house when laid

The joists had been in for a good few months from around Aug to Dec with no coverings on them. Around early December I started to lay the insulations boards in preparation for the UFH pipes. Late December and early Jan is when the tiles went on, the house had very little heating and it was snowing outside or very cold - 0C-5C. I did turn on the UFH in parts of the house that had no tiles on them (just the plys) to try and bring the temp up a little, I'd say the temp inside was anywhere between 2C-7C.

From a plumbers point of view, max depth for a notch in a 9inc joist is 22.86mm (1/8 joist depth). They look like at least 35mm if the pipe is approx 15mm. There should be at least 6 inc gap between the notches. (3x joist thickness.There looks like 4inc ) Floor & Roof joist notches
There are also distances from the brick supports (see link).
This might be part of the problem.

I'm surprised at this, I didn't adhere to these guidelines but I've never had a problem before but I'll take your word on this.

So deflection is causing all of these problems eh? I would never have guess it! I've got the fireplace installer in today and once he's out of the house I'll get one of these tiles up.

Thank you for your help everyone, I really appreciate it.

[Sir Ramic]

Keeps us informed, we love a good mystery....and happy endings too .

[Indy]

Keeps us informed, we love a good mystery....and happy endings too .

Thanks Sir Ramic!

Lets hope that this is one Scooby mystery can we can solve, it just that I never would've thought that the bad guy behind the mask would be me all along.

[Sir Ramic]

Lifting that tile could reveal more info.

[andy-p]

There is something thats been puzzling me , Ardex AF200 (which i looked up on t'internet) is a carpet adhesive that is suitable for ufh , i usually use a S1 or S2 cementious adhesive for sticking down a d/c mat , im not saying thats the problem just wondering...

[Indy]

Andy - Ardex AF200 is what Schlutar recommend for laying down Ditra Mat, it's official - honest. I didn't buy it from the car boot sale either..

The underside of Ditra is carpet like so it does kinda add up, I just can't wait to pull the bugging tile up and know for sure.

[Rich]

Oh dear. Its horrid when we get posts like this, must be even worse when its in your house!
There is not much more I can add to the posts above, as has already been said, the first thing you need to do is take one or two tiles up and take some pics of the floor but also take some of the under side of the tile, I will be interested to see if the bond has been broken between the adhesive and tile or adhesive and the floor.

look forward to getting more info on this one.