Bowed walls and cracked tiles

[jack]

I think I may have mentioned this in passing at some point a while ago, but I'm now revisiting this issue.

 

A few months after we moved in, I noticed that we had vertical cracks through the marble tiles in our ensuite.  Shortly afterwards, I noticed that in fact there were vertical cracks in all of the bathrooms.  The cracks follow the lines of the board joints underneath.  We have Hardibacker or some other sort of tile backer board in these areas.   

 

I initially wondered whether it was the house settling along the line of the bathrooms, but the pattern just doesn't fit, plus there's no similar cracking anywhere else in the house.  

 

I was about to start chipping out the tiles today to replace them when I noticed how much the walls have bowed in these areas.  A couple of examples:

 

Crack in marble:

 

Crack in tile:

 

Bowed wall:

 

 

I did initially wonder whether it was to do with water, but it's happened even in the second ensuite shower, which hasn't yet been grouted and has never been used.

 

My next guess is that the adhesive (flexible cement-based for the marble, as recommended by the supplier) has wicked into the hardibacker and caused it to swell and bow.  It just seems like a lot of bowing for that sort of material.

 

I'm about to start chipping away at the cracked tiles to replace them, but I'm a little concerned that I don't know the cause.  I'm also slightly worried about leaving the bowed sections as they are, but short of tearing everything down and starting again, I can't see what else I can do!

 

Help please?  

[Temp]

That's pretty strange. Our bathroom was clad in travertine over Hardi backer board with no issues.

 

I'm wondering if your joints weren't done on studs? Is it the centre of a sheet bowing out or the edge bowing in?

 

Edit: Looking at that last picture it looks like the centre of sheets bowing outwards. Were they screwed to all the studs or just along joints?

 

Edited April 1, 2017 by Temp

[jack]

I wasn't there, but pretty sure the joints were done on studs.  

 

As far as I can tell, it's the centre of the sheet bowing out.

[Temp]

I suspect they didn't screw the Hardi to the middle/all the studs.

 

Got a metal detector/stud finder (eg to look for the screws)?

Edited April 1, 2017 by Temp

[Declan52]

A strong magnet will also detect any screws as well.

[Ferdinand]

@jackI think it is a different thing, but I have floor tiles cracked in my bathroom on 8"x4" lines.

 

I think the cause is the use of the wrong type of chipboard to cut a corner (ie the same chipboard as the other upstairs rooms), which has swelled. I can post photos if you like.

 

Ferdinand

 

Edited April 1, 2017 by Ferdinand

[Gone West]

Was the Hardiebacker fitted tight when very cold and could it be due to expansion when it warmed up?

[Construction Channel]

how soon after the walls were built did it get boarded and tiled?

 

My only thought would be that maybe the studs have shrunk and pulled the screws through the board?? it is a bit worrying that it has happened so often though.

 

I think you have got to take at least the broken tiles off and do some investigation.

 

+ one to a strong magnet just to see how many fixings are behind the in tact tiles

[ProDave]

 

Check for straightness vertically. Have the studs warped?

[Jeremy Harris]

Another vote for it being a problem caused by fixings.  I think there is a very good reason that our resident expert plumber/bathroom fitter/heating engineer gets a bit focussed on using lots and lots of fixings!

 

My experience with slight movement in our house has been that there is a small (perhaps 0.5mm) shrinkage of the skim plaster away from most of the windows, and a dozen or so pops in the skim where screws are, plus a very fine crack that appeared in a joint between two bits of plasterboard high up in the entrance gable (since filled and repainted and now seems fine).

 

The main area where there was shrinkage was the additional MDF covered thin "stud" wall I added to build our walk-in wardrobe.  That stayed in one ~4m long, ~2.2m high piece, but shrank away from the ceiling and wall joints on either side by around 1mm.  My guess is that it's because I didn't leave enough time for the timber to stabilise inside the house before I built the wall.  Since filling and re-painting it it's not moved at all.

 

It's hard to see how shrinkage in the structure could force the board to bow out that much if it was secured well to the walls.

[jack]

Thanks for all the feedback guys, very useful.

 

2 hours ago, Temp said:

I suspect they didn't screw the Hardi to the middle/all the studs.

 

Possibly, yes.  Just seems odd they wouldn't do it here when the same people plasterboarded the rest of the house as well and always used screws across the face of the boards.

 

2 hours ago, Declan52 said:

A strong magnet will also detect any screws as well.

 

Ha, yes, I spent half an hour earlier today looking for the neodymium magnets I know have somewhere, but no luck.  Might need to get hold of one.

 

2 hours ago, PeterStarck said:

Was the Hardiebacker fitted tight when very cold and could it be due to expansion when it warmed up?

 

It was fitted in late summer 2015, when the house had been wind-tight for several months.  It's been at the same temperature +/-2 deg C ever since.

 

2 hours ago, Construction Channel said:

how soon after the walls were built did it get boarded and tiled?

 

Walls went up by MBC in early 2015.  Boarding and tiling took place September or so.

 

1 hour ago, ProDave said:

Check for straightness vertically. Have the studs warped?

 

They seem pretty straight vertically. If they've warped, then they've warped in each and every bathroom wall (as well as our downstairs shower) and not in a single other place!

 

1 hour ago, JSHarris said:

It's hard to see how shrinkage in the structure could force the board to bow out that much if it was secured well to the walls.

 

I suspect you're right, it's just hard to believe that they'd do this given that all the other plasterboarding they did was properly screwed to the walls. 

 

I've taken off a tile on a crack and this is what I can see (ignore bloodstains - spent 20 seconds trying to find dirty water that I thought was leaking in before I realised I'd cut my fingertip!):

 

 

The board is darker than it looks in the photo, but it's clearly some sort of cement board.

 

By way of background (and this is all from memory), I came home from work one day to find they'd used water-resistant plasterboard where the showers were.  I said I wanted something stronger and more permanent, so we agreed I'd pay for them to take this down and replace it with proper waterproof backer board.  This looks very dark to me - darker than the tile backer board we used under the floors a bit later (again involving an argument about what had been agreed in advance - please, please make note of everything that's agreed both upfront and along the way, and put it in writing, either in a site diary or by emailing the person involved as soon as you've had the conversation!) 

 

I wonder whether what's been used isn't a tile backer board but is instead some sort of cement board that isn't rated for this sort of application?

 

Another comment: I can't get a photo, but I was able to take off an access panel and get at the inside of our built-in bath (white tiles in second pic above).  I can just see where the edge of the board is joined to the frame.  It looks like a couple of screws have partly pulled through the board (which is the same grey stuff as above).  The structure here isn't quite the same as the rest of the walls, as the tiler did it.  The verticals on the built-in bath are a lot further spaced than the studs everywhere else, which actually could emulate quite well the structure if fixings haven't been used on the studs between the edges of the board.

 

Still a bit of a mystery what's caused the swelling, even if the fixings turn out to be the problem.  While two of the three showers have been used, one hasn't been and it has the same problem.  It therefore isn't (or isn't just) moisture from use that's problem.  

 

Next step is to get hold of a magnet or studfinder and see what I can learn about fixings.

[Nickfromwales]

In the last pic I can see some sort of straight strip / joint. What is it?

Also, how the hell can we see a drywall screw head, and even worse it looks proud of the adhesive? The tile adhesive has been blobbed on too, rather than solid bed. . None of the affixed area should be void of adhesive. 

Take the tiles off jack, as otherwise this is just guess work tbh. Seeing that regular plasterboard screws have been used is not good. 

[jack]

Thanks Nick.

 

If you mean the vertical white strip, it looks like a line of sealant of some sort.  White mastic that's been squeezed into the joint, I guess.

 

Re: drywall screw heads and adhesive, I wasn't here for them doing this stuff, so I don't know what they used.  I wouldn't be at all surprised if they used drywall screws, and yes, that one's not been driven all the way home.

 

I wasn't blown away with the quality of the tiling generally, but this subcontractor was via the guy who I've mentioned in the past as having had problems with.  Everything we raised as an issue was apparently us having "unrealistic expectations of quality".  He walked off in a strop when I pointed out that one of his guys had unscrewed and discarded a piece of protective steel over the 240V cabling to one of the external blinds, right in the corner of the window where a future owner might drill to install blinds or curtains.  He's actually a really nice bloke, but clearly incapable of dealing with conflict (I was always positive and took a "how can we solve this" approach when raising issues with him).

 

Worse, he's peripherally in our social group locally, so we run into him at parties now and then.  That made it really awkward to push too hard.  In the end we just threw our hands up and wrote it off to experience.

 

Still, if it turns out that they've installed this incorrectly, he'll fix it at his cost or we'll see him in court.

 

I'll pull some more tiles off tomorrow and take some more pics.

[Triassic]

Is that flooring grade chip board ?

[Declan52]

If that is a join in the boards should there not be more screws visible. At least one in the corner and some along the top plus maybe another along the join.

[Construction Channel]

I'm still struggling to understand how this has happened in so many places. 

the bends in the wall may have been to do with the tiles on the odd occurrence but it makes no sense on this scale,

the fact they don't have a full bed for the tiles worries me even more. I dislike people "dobbing" patios let alone bathrooms!

 

how did you go about the contract? was there a snagging list?

 

if they have used plasterboard screws they won't have pulled through like i suggested in my last comment as they will all be proud.  (backer board is a bastard to get into without a cutter head)

 

This is not my field so probably best to let Nick to sink his teeth into this one But if the company you used has any kind of reputation to uphold. call them back in to see what has actually happened and see what excuses they try to come up with.

 

someone has f*ked up somewhere and if you paid for a professional job there is no reason you should end up bleeding for it

[Jeremy Harris]

Not sure if it's just the angle of the photo or not, but that tile adhesive dob looks pretty thick, almost as thick as the tiles.

 

I'm no expert at tiling, but I've always used a toothed spreader to lay a complete covering of adhesive, to a fairly constant thickness, with the grooves allowing the tiles to be pushed down to the right depth to be flush with each other.  Not sure of the right way to work, but I've tended to cover enough for a row and a bit of tiles at a time, rather than just dob stuff on for each tile.

[Nickfromwales]

Get one elevation stripped of tiles and adhesive. Then simply push against the backer boards to check for movement / fixings etc. Let's find out how many screws and where before we speculate any further.  

Fwiw, I've blobbed tiles on many a time, but only in instances where they've been on horrendously uneven walls and I've had to pull the wall plumb and straight ( large shower cubicle etc ) so it can be done. I always use cementitious adhesive in theses cases, NOT ready made acrylic stuff, as the latter can only be applied 5mm thick at most as it just doesn't set, literally for weeks, otherwise. 

If you have a non-porous background like cement board then you should not be using acrylic full stop, and the same goes if it's a porcelain tile as the moisture just doesn't have anywhere to go. 

Same applies again if the area has been tanked, regardless of tile type. 

@jack, do you know what type was used? Tub or bags of powder. ?

[Ferdinand]

12 hours ago, Triassic said:

Is that flooring grade chip board ?

 

For me I assume.

 

I have not taken up the tiles so cannot comment authoritatively but that is my assumption, and there is electric ufh which would aggravate temperature cycling. We are living with it until we partly redo the bathroom in a year or two - and in fact one inexpensive option would be simply to vinyl over the top wit a thicker than usual foam underlay.

 

However the adjacent landing is chipboard and I am thinking it will be the same stuff, since there are a few signs of some corner-cutting elsewhere, or perhaps a realisation that extra spending would not be reflected in sale price. I really can't fault people for being prudent, but this one did not work.

 

Ferdinand

 

Edited April 2, 2017 by Ferdinand

[jack]

13 hours ago, Triassic said:

Is that flooring grade chip board ?

 

No, definitely some sort of cement board.

 

13 hours ago, Declan52 said:

If that is a join in the boards should there not be more screws visible. At least one in the corner and some along the top plus maybe another along the join.

 

Yes, it's a definitely a join between the boards.

 

10 hours ago, Construction Channel said:

how did you go about the contract? was there a snagging list?

 

Some background might help.

 

We didn't have a main contractor.  MBC built our frame and we arranged follow-on trades to come in and do the rest of the work.

 

As to how this guy got involved, as I think some of you know, we have brick slips on most of the house, and timber cladding on the rest. The first outfit we had fixing the brick slips did an extraordinarily poor job. My children could easily have done better than they managed. After giving them a couple of opportunities to lift their game, we eventually parted company.

 

By this stage, we were extremely stressed (the brick slips guy had gotten borderline threatening at one point) and decided that even if it cost a bit more, we needed to get someone in that we could trust. We'd had a builder acquaintance of ours price some work previously. Really nice guy.  Other friends of ours who had used him had given glowing reports about the quality of his work, but we had been a little sceptical about using someone we knew, and he wasn't particularly cheap. By this stage, however, we were desperate to just get someone in who we could rely on, so we got him in to price for fixing the rest of the brick slips. 

 

He engaged the tiler who did the tiling above to fix all of the brick slips, and he did a reasonable job for the most part. I chalked the occasional imperfections up to the frankly pretty useless brick slip system that we had gone with, although knowing what I've since learned that might be a little generous.

 

The same builder also arranged for the cladding work we needed doing at around the same time. The first guys he had doing it were absolutely brilliant, but at some point they became unavailable (it was all a bit mysterious - I think they had some money issues).  The next guys weren't as good, but after a few friendly chats with them and the builder, things improved.  I suspect, but don't know, that the builder underpriced the cladding job, and that this perhaps coloured our relationship with him going forward.  

 

Once the brick slips were finished and we were moving on to plasterboarding and tiling, we decided to get this guy to price again.  With hindsight, this was a mistake. The builder himself was involved in the boarding, along with the tiler and another guy had been doing a lot of pointing of the brick slips. They had clearly done this before, as they really cracked on and did a pretty decent job. We had problems with their attitude to things like soundproofing (pretty sure I've mentioned before that they just slung the sound insulation up into the ceilings without making any effort to bridge the spaces between the joists), and I was annoyed by the sizes of some of the gaps that were left around, e.g., MVHR outlets and metal back boxes, but overall the finish was pretty good.

He also supplied the guys who did the carpentry (door, door linings and skirtings).  We weren't that happy with some of the work and it was an absolute nightmare trying to get him to admit that work wasn't acceptable.  Part of the reason we decided to have him do all of this was that if it went wrong, there'd be no question who was at fault.  

 

Since the jobs were added piecemeal and we never really considered him a main contractor, there is no formal contract in place other than the general letter he sent with quotes. Towards the end of his interaction with us, it became clear that his idea of what was a "snag" was very different to ours.  With our suspicions that he'd lost money on the cladding, we'd decided that for some of the bigger jobs we would go on a day rate. Some of the other stuff (carpentry, from memory) was done on a fixed price. When we pointed out a few snags on the day rate work, he told us that he "didn't have the margin on day rate work to redo work".  But then when we pointed out a few snags on the fixed-price work, he told us that he "didn't have the margin on fixed-price work to redo work"! We were certainly left wondering what the hell we were paying him these margins to do, given that we'd probably paid for something like 100+ man days of his sub-contractor's time.

 

We eventually got him to fix the worst of the snags, but we were left with a nasty taste in our mouths.  It was difficult because we see the guy around socially a bit.  I'd have been perfectly happy to push it but my wife wasn't happy about potentially poisoning things locally, so in the end we just bit our tongues and planned to rectify the bits we weren't happy with ourselves.

 

Anyway, probably more background than you need or want, but there it is.

 

10 hours ago, Construction Channel said:

if they have used plasterboard screws they won't have pulled through like i suggested in my last comment as they will all be proud.  (backer board is a bastard to get into without a cutter head)

 

Perhaps if they're there but proud, they actually aren't holding the board flat and were able to be pulled through until they engaged the heads?   

 

3 hours ago, JSHarris said:

Not sure if it's just the angle of the photo or not, but that tile adhesive dob looks pretty thick, almost as thick as the tiles.

 

Yes, it's pretty thick.

 

2 hours ago, Nickfromwales said:

@jack, do you know what type was used? Tub or bags of powder. ?

 

For the marble, we definitely used flexible cementitious (Topps Tiles branded stuff, I believe).  The supplier was pretty adamant about the importance of using that.  

 

I'm not sure about the other tiles, but reasonably sure he used the same stuff.  I know that whatever he used was bagged.

 

One more data point that for me actually adds to the mystery - this is what the interface with the shower tray at the bottom of the crack looks like:

 

 

That picture makes it looks slightly worse than it is in real life.  The close-up is a bit more accurate:

 

  

This looks to me like the stud that the crack is along has pulled away from the tray.  The only other option is that the entire tray has moved with the bowing of the wall, which seems unlikely.  Again, I wasn't here when the tray was put down, but I believe it was put onto a plywood base and glued down pretty extensively with Sticks-Like-Sh*t adhesive.

 

I've got some things to do today but will take down some more tiles later and see what's behind them.

 

Thanks for all the help so far.

[Onoff]

Making me paranoid about my studding and boarding all this! Just thinking of questions to ask!

[Nickfromwales]

This stinks of the backer boards not being fixed properly to me. 

[Gone West]

If it is Hardiebacker it's more difficult to screw than plasterboard. They may have reduced the number of fixings. I drilled and countersunk mine and used s/s screws.

[Jeremy Harris]

I can fully appreciate the challenges of finding people that you can trust to do a job that meets your own standards; we had a couple of people that were bloody awful, and I did find it difficult to just tell them that I wanted them off site and didn't want them back.  From talking to others locally, I think we were just very, very lucky. 

 

After having been let down by three brickies, in desperation I rang around everyone local I could find and came across one guy who was a real perfectionist.  So much so that he carefully pointed up a block wall that we were going to render, and when I said that he didn't really need to bother with how that wall looked, his reply was that he couldn't go home, knowing that the wall didn't look spot on, out of pride in his own workmanship. 

 

He recommended a chap to do the rendering, saying he was the only person he would trust to do a good job, and he was spot on, so not only did we get that chap to render the big walls around the house but we also got him to board and plaster skim the whole house, and he was damned good.  In turn, the plasterer recommended a tiler and decorator, and he was another perfectionist (I reckon he would probably be a good match for Nick, in terms of his attention to detail).

 

The tiler, in turn recommended the landscaping guy, who was so good that we've had him back about three times now to do more work around the place.  So, for all of the "finish-critical" stuff that I wasn't doing myself we used people that had, indirectly, been found as a result of employing that first-class brickie.  I'm near-certain that this is the best way to find good people, as anyone who is good and takes pride in their work will not recommend anyone that has lower standards than their own.  The challenge is getting into that network of good people!

Edited April 2, 2017 by JSHarris
typo

[PeterW]

19 minutes ago, JSHarris said:

So much so that he carefully pointed up a block wall that we were going to render, and when I said that he didn't really need to bother with how that wall looked, his reply was that he couldn't go home, knowing that the wall didn't look spot on, out of pride in his own workmanship. 

 

He's related to my brickie then ..!! Every joint internally is pointed and checked so we have no airtightness issues ..!