3 week old tile job already cracking - solution?

[Thywillbedone]

Thank you for spending the time on this.

Haven't cracked how to copy messages but here are the answers as far as I know:

1. The plywood was WBP exterior grade. It was fixed direct to joists with screws and "no more nails" glue.
2. I don't know what acrylic primed means but I don't think it was done.

3. Not sure about primer

4. Tiles are porcelain floor tiles...about 20cm x 20cm

5. Span of joists in problem bathroom is short as it is in a loft extension which sits on steel beam frame/cage if you know what i mean....two steel beams run either side of bathroom and joists run from steel beam to steel beam...I would say span of wooden joists is 6 ft at most.

6. Re grout full depth, I tried getting a coat hanger in to the hole between floor and grout...it runs in about 5 cms from the edge of the tilework...but the cracking is in the middle of the floor...I can only conclude that there is empty space under the cracking as the grout is falling through

7. See my response re addy used. I'll check later

8. Re floor flex, I almost can't believe it is happening given the small space involved...there is a full length bath plus toilet and sink but only room for two people standing besides all of that!

9. Builder was recommended for this type of work. The whole project became a renovation of three bathrooms which were not in bad condition...just wanted to update/improve. Other work included work on floors in bedrooms and complete repainting.

10. Noted re grout around the bath.

11. Should all perimeter edges of a tiling job be silicone rather than grout...to allow movement?

12. The ply is on the floor...its not a wetroom. The walls are plasterboard.

13. By first chance I mean, I expect a professional to get it right first time...this wasn't a technical job by any means as far as I was told

14. I can't see if there are gaps between tiles and floor...the gaps I am talking about are between the floor and the underside of the grout i.e. the grout appears not to completely fill the spaces dividing the tiles

15. I don't know what trowel was used

16. Ivory grout was used

17. Can't see there is any sign of adhesive failure but perhaps I need to test a bit more? Any tips on this?

18. The tiles in the problem room were different from the other two rooms...the grout for the other rooms was a Black Bal Microflex grout which is not showing any problems as yet

Thanks again for looking at this. I need to find out what mix of addy was used and will report back. [/list]

 

[Thywillbedone]

Well Richard, I'm sure you put the op's mind at ease

I'm panicking now, and it's not even my bathroom

I am holding quite a bit of money back from the builder so I hope he is incentivised to fix the issues!! I'm just not sure any more that his guys have the know-how and maybe I should get someone else to do it. Any recommendations for NW2 London?

 

[Richard C]

1. The plywood was WBP exterior grade. It was fixed direct to joists with screws and "no more nails" glue.

24mm thick is at the top end so should be OK but depends on joist structure. Screws are all I use, I would not have used NMN & it’s not necessary. The ply needs to be fully supported by & tight against the joists, introducing a “NMN glue sandwich” is just something else that could fail in the longer term leading to gaps forming & movement.

2. I don't know what acrylic primed means but I don't think it was done.

Ply floors or overboard should be sealed on the back face & edges with an acrylic primer to prevent moisture getting in which can cause the ply to warp. It’s important & should be done but isn’t a critical risk unless there is high ambient moisture or large moisture variation within the building.

3. Not sure about primer

BAL do not recommend priming the tile surface of ply with cement powder adhesives, it can affect adhesion.

4. Tiles are porcelain floor tiles...about 20cm x 20cm

OK; not that large.

5. Span of joists in problem bathroom is short as it is in a loft extension which sits on steel beam frame/cage if you know what i mean....two steel beams run either side of bathroom and joists run from steel beam to steel beam...I would say span of wooden joists is 6 ft at most.

What size & pitch are the joists?

6. Re grout full depth, I tried getting a coat hanger in to the hole between floor and grout...it runs in about 5 cms from the edge of the tilework...but the cracking is in the middle of the floor...I can only conclude that there is empty space under the cracking as the grout is falling through

The grout should be full depth; hopefully that’s all that’s caused the problem.

8. Re floor flex, I almost can't believe it is happening given the small space involved...there is a full length bath plus toilet and sink but only room for two people standing besides all of that!

If the floor is in aloft extension suspended between steel channels, could it be possible the whole frame has some movement or something is happening to cause the floor to twist/flex!

11. Should all perimeter edges of a tiling job be silicone rather than grout...to allow movement?

Yes; silicone anywhere where there is likely to be differential movement between adjacent surfaces; even flexible grouts have very little flex & will crack.

14. I can't see if there are gaps between tiles and floor...the gaps I am talking about are between the floor and the underside of the grout i.e. the grout appears not to completely fill the spaces dividing the tiles

OK but the grout should be full depth; hopefully that’s all that’s caused the problem; try letting them re-grout & see what happens; I would suggest you try using Superflex (which also comes in Ivory) rather than Microflex which I would normally only use on walls.

15. I don't know what trowel was used

For tiles that size, a solid thick bed trowel - 20mm round notches, 10mm deep, at 28mm centres.

16. Ivory grout was used

As I said, not an ideal colour for floors.

17. Can't see there is any sign of adhesive failure but perhaps I need to test a bit more? Any tips on this?

I would not advise you start jumping up & down on the floor, that may be asking for trouble; if it’s going to fail, it will show itself in due course.

18. The tiles in the problem room were different from the other two rooms...the grout for the other rooms was a Black Bal Microflex grout which is not showing any problems as yet

If all rooms use the same adhesive over the same floor type with similar tiles, the other two rooms are OK & the only affected room is in a loft conversion, I’m wondering if this may be a more significant factor than adhesive choice or other possible mistakes in using it.

I need to find out what mix of addy was used and will report back.

As opposed to other BAL powder adhesive products, CTF4 is not primarily listed a flexible adhesive. BAL specifically states that it’s only suitable for timber floors when modified with BAL ADMIX AD1; this is what gives it the required flexibility.

It would be good to get clarification on the joist size & certainly if Admix AD1 was used on the adhesive but to sum up;

• You must give him the opportunity to put things right or you could have problems withholding payment.
• The grout should be full depth or it’ll have little support & hopefully that’s all that’s caused the problem. Let them rake out (make sure they do it properly) & re-grout & then see what happens. I would suggest you try using Superflex (which also comes in Ivory) rather than Microflex which I would normally only use on walls. Although Microflex is listed as suitable for use on some floors, the BAL detail spec sheet doesn’t specify it for use on floors at all! It may be worth giving their technical dept a quick ring for clarification.

 

[Thywillbedone]

Thanks.
1. Not overly worried about moisture variation

2. Re joist size and pitch...size looks standard to me

3. A colleague pointed out that the tiler might be treating the grout as 'decorative' rather than performing a holding function (which the addy is capable of doing on its own?)...I think he may have a point here. Does the grout have a holding function or is it decorative? Either way, it shouldn't be crumbling

4. I don't know about flexing of the steel in the conversion...its a Victorian conversion so anything is possible. New build is next on the menu i think!

5. I need to check all perimeters tonight to make sure they are silicone and not grout

6. The only reason I don't want to "see what happens" if they re-grout is that I have new carpets coming in at much expense...and I don't want works going on afterwards. I accept that i may have to go that route though

7. What colour grout would put with cream tiles - assuming you are an interior designer as well

8. I'll give BAL a call, thanks

 

[Richard C]

1. Not overly worried about moisture variation

But the ply might be.

2. Re joist size and pitch...size looks standard to me

No such thing as a standard joist size; pitch is usually 400mm but not always.

3. A colleague pointed out that the tiler might be treating the grout as 'decorative' rather than performing a holding function (which the addy is capable of doing on its own?)...I think he may have a point here. Does the grout have a holding function or is it decorative? Either way, it shouldn't be crumbling

No tiler of any merit would treat grout as decorative in that sense; well penetrated grout lines are almost as important as the adhesive.

4. I don't know about flexing of the steel in the conversion...its a Victorian conversion so anything is possible.

I didn’t mean the steel was flexing (although steel will flex); I was thinking more in terms of the method of construction & support causing differential movement between them.

7. What colour grout would put with cream tiles - assuming you are an interior designer as well

Grey goes with practically anything but a dark contrasting brown would look good IMO, especially on thinner grout lines.

 

[tictic]

9/10 any cracking in floor grout,is signs of a de-bonding off the floor tiles and the subsrate...tap the tiles to see if any sound hollow...

the first pic the grouting looks as if he /she has washed off to early and the grout in places has sunk..or a (souped mix) ie to waterer...

the bath should have been fitted sealed, min half fulled with water over night..before any tiling...and sealed with silicone not grout..

the floor tile pic with the grout...cant really see it that well,but is there a gap between grout and floor or is it half filled with floor adhesive?

 

[Thywillbedone]

Very helpful replies. I have now checked out all products used.

Two bathrooms (with no visible problems):
Black floor tiles - BAL Micromax Grout Ebony
White wall tiles - BAL Micromax Wall Grout White

Problem bathroom:
Cream wall tiles - BAL Micromax Grout Ivory
Cream floor tiles - Wickes Floor and Wall Tile Grout

I had not specified the Wickes product but it seems the Topps Tiles guys didn't pack anything to grout the floor of the 3rd bathroom and my builder improvised with the Wickes product.

In terms of addy, i bought:

BAL CTF4 White (3 x 20kg) - I assume this was used for all wall tiles
BAL Stone & Tile PTB White (1 x 20kg) - I assume this was used for 3rd bathroom as there is still some left over
BAL Stone & Tile PTB Grey (1 x 20kg) - I assume this was used for two bathrooms with black tiles

In answer to some questions:
- i think the floor adhesive has been used generously
- i will tap the tiles later to check
- i've established that grout should not have been used around the bath...it has been on one side, everywhere else is silcone
- bath was filled while setting
- starting to think that the mix of the Wickes product wasn't right or was washed off too early
- i plan to ask the builder (1) that the floor area in the problem bathroom needs to be regrouted (2) remove grouting in any perimeter area and around bath...replace with silicone (3) other?

Any other suggestions would be most welcome!

 

[Thywillbedone]

RichardC, re the joist...I think it looked about 400mm.

Thanks the suggestion re grout colour...I think i will change from ivory to one of those suggested colours

 

[Richard C]

So it’s Micromax not Microflex (whch is OK) but your builder didn’t use that because there wasn’t enough, went out & bought a crappy own brand product without consulting you & the tiler didn't use it correctly.

Problem bathroom:
i plan to ask the builder
(1) that the floor area in the problem bathroom needs to be regrouted
(2) remove grouting in any perimeter area and around bath...replace with silicone

Wouldn’t disagree with that. make sure they use BAL who, incidentally, do a colour matched Mocromax silicone for those areas you need it.

 

[Thywillbedone]

Just noticed I made a mistake in reading the receipt:

For the white wall tiles, it was BAL Microflex Wall Grout (not Micromax)
For the cream wall tiles, it was again BAL Microflex Wall Grout

Schoolboy!

 

[Richard C]

Slapped wrist for you, get your products right it is important My previous recommendation about trying Superflex stands then. You could try Micromax & on paper it looks ok but is "new" & I haven’t personally tried it.

BAL seem to bringing out many new products lately, a bit like soap powder manufacturers I’m a little dismayed by it & tend to stick with what I know works.