Bowed walls and cracked tiles

[jack]

Unfortunately, today took a different turn than expected and I wasn't able to get to the tiles.  I'll try to get to them early this week.

 

5 hours ago, JSHarris said:

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.  

 

My wife and I are arguing about this at the moment in relation to the remaining bits and pieces we have left for completion.  She wants to pay someone to do it, but since it's all stuff that's visible I want to do it myself to make sure it's done properly (or at least I'll know I tried!)

 

We've just been let down time and time again, even when we've had great references from people, made it clear (we thought!) the level of quality we were after, and in more than one case offered more money for people to slow down and do the bloody job properly!  I became convinced in the end that it's less laziness or a lack of pride, but the inability to actually appreciate what a decent job looks like.  If you don't know that, what hope have you of achieving it?

 

I can think of only a two or three people on our job who had this attitude.  Most others were nice guys, who did a workmanlike job and no better.

[Temp]

Get that metal detector/magnet going to see if that narrows it down to either a or b... 

 

a) Middle bowed out - no screws in the middle?

b) Joints bowed in - no studs or screws near the cracks?

 

If you have one of those USB cameras it would be interesting to look down into the wall from above.

 

Most cement boards have some sort of marking on them at least on one side.

 

 

 

 

 

[Ian]

For the tile backer panel to have bowed like that there must be a problem with the fixings - either they have pulled through the board or they are missing altogether.

 

Different tile backer boards have differing fixing requirements e.g. Wedi's system involves washers to spread the load. Knauf Aquapanel needs special screws applied using torque control as they aren't supposed to break the surface skin of the board - If you break the board paper or core with the screw head it invalidates any warranty.

Edited April 3, 2017 by Ian

[Onoff]

Well Blondie here is sinkin' em flush:

 

 

[Bitpipe]

Sorry to hear about this Jack, can only imagine how upsetting this is.

 

We used waterproof (green) pb in the bathrooms and had it skimmed before tiling, tanking shower areas first - seems to be pretty bombproof, as evidenced by the difficulty we had in removing some tiles to find a leak.

 

Only used 6mm backer boards on the floor and these had UFH mats and then latex before tiles - these ones used the washer & screw system and I was surprised at the number of fixings the tiler used.

 

[Nickfromwales]

12 minutes ago, Bitpipe said:

I was surprised at the number of fixings the tiler used

 

I was pleased at the number of fixings the tiler used

 

 

[jack]

1 hour ago, Bitpipe said:

We used waterproof (green) pb in the bathrooms and had it skimmed before tiling, tanking shower areas first - seems to be pretty bombproof, as evidenced by the difficulty we had in removing some tiles to find a leak.

 

Yes, I'm feeling particularly smug about having asked them to take down the water-resistant (not waterproof!) green plasterboard in order to put up this "better" backing board! 

 

I was talked out of tanking as being "overkill".  The point was made that if water got through the tiles, it would find a way past the tanking under the shower tray and then have nowhere to go.

 

This is the same guy who just wanted to use PVA everywhere.  I got him some SBR for under the floors and his initial response was it was just overpriced PVA.  When I read him the ingredients list he agreed there was a bit more to it.  

 

There just seems to be this "take the simplest/quickest way forward" attitude with a lot of UK tradespeople.  It isn't cost cutting, because we were buying materials and paying a day rate for a lot of this stuff.

 

The real shame about all of this is that the tiler is a really great guy, who worked hard and mostly did a good, if not always stellar, job.  When picked up on things he was responsive to fixing them.  It's just I wasn't always able to be there to keep an eye on how things were being done. 

Living and learning...

[MrP]

1 hour ago, Bitpipe said:

Sorry to hear about this Jack, can only imagine how upsetting this is.

 

We used waterproof (green) pb in the bathrooms and had it skimmed before tiling, tanking shower areas first - seems to be pretty bombproof, as evidenced by the difficulty we had in removing some tiles to find a leak.

 

Only used 6mm backer boards on the floor and these had UFH mats and then latex before tiles - these ones used the washer & screw system and I was surprised at the number of fixings the tiler used.

 

 

Just a heads up on the green pb, British Gypsum actually advise not to skim the board when tiling an area. From memory the rating almost doubles in regard to how much weight of tile the board can carry when it is not plastered as you get better adhesion of the tile adhesive direct to the board, particularly useful if you are using a stone tile or large format porcelain. Plus you save on money not plastering the area also .

[Bitpipe]

38 minutes ago, MrP said:

 

Just a heads up on the green pb, British Gypsum actually advise not to skim the board when tiling an area. From memory the rating almost doubles in regard to how much weight of tile the board can carry when it is not plastered as you get better adhesion of the tile adhesive direct to the board, particularly useful if you are using a stone tile or large format porcelain. Plus you save on money not plastering the area also .

 

Yes, I was told this after the room had been skimmed but we used 600x300 porcelain tiles and they went on fine.

 

[Ian]

2 hours ago, Onoff said:

Well Blondie here is sinkin' em flush:

 

 

@Onoff Dodgy place the internet when it comes to advice!...I couldnt work out if that video was supposed to be an official one from Aquapanel but it's definitely wrong regarding the screw depth. You'll see the correct method on Aquapanel's website. Quote: http://www.knauf.co.uk/technical-assistance/technical-faqs

 

"The correct use of the correct type of fixings is vital to both the strength of the whole partition and to prevent future problems, such as cracking of the joints. Plasterboards should be fixed securely to all supports, using approved Drywall Screws, working from the centre of each board. Screws should be positioned not less than 10mm from the board edge, at 300mm centres - reducing to 200mm centres at external corners. Screw heads should be set in a ‘depression’, and the screw gun torque set so that neither the board paper or core are broken."

 

I was involved recently with a high-rise project in london where we had to complete a job where the client was suing the contractor in a multi-million £ claim because they had over tightened the Aquapanel screws in dozens of bathrooms that were to be clad in marble. Part of our contract work was to replace all the Aquapanel.

Because it was high-rise the building had to be able to cope with significant movement in high winds without anything falling off walls. At the top it moves about 400mm.

Edited April 3, 2017 by Ian

[Onoff]

3 hours ago, Ian said:

@Onoff Dodgy place the internet when it comes to advice!...I couldnt work out if that video was supposed to be an official one from Aquapanel but it's definitely wrong regarding the screw depth. You'll see the correct method on Aquapanel's website. Quote: http://www.knauf.co.uk/technical-assistance/technical-faqs

 

"The correct use of the correct type of fixings is vital to both the strength of the whole partition and to prevent future problems, such as cracking of the joints. Plasterboards should be fixed securely to all supports, using approved Drywall Screws, working from the centre of each board. Screws should be positioned not less than 10mm from the board edge, at 300mm centres - reducing to 200mm centres at external corners. Screw heads should be set in a ‘depression’, and the screw gun torque set so that neither the board paper or core are broken."

 

I was involved recently with a high-rise project in london where we had to complete a job where the client was suing the contractor in a multi-million £ claim because they had over tightened the Aquapanel screws in dozens of bathrooms that were to be clad in marble. Part of our contract work was to replace all the Aquapanel.

Because it was high-rise the building had to be able to cope with significant movement in high winds without anything falling off walls. At the top it moves about 400mm.

 

And THIS from Knauf; 15mm edge distance, 250mm centres, the same panels and screws as I have:

 

https://www.google.co.uk/url?sa=t&source=web&rct=j&url=http://www.siginsulation.co.uk/Literature/Aquapanel%20Leaflet.pdf&ved=0ahUKEwj4wqSk_ojTAhXlIsAKHbShAq8QFgg4MAM&usg=AFQjCNHIvn1VhjvRVUiPI5vDY9_SSMUHqQ

 

Go figure!

 

Yep, seen some utter crap put in and good materials put in badly (I too work in London in high rise buildings).

[Nickfromwales]

6 hours ago, MrP said:

 

Just a heads up on the green pb, British Gypsum actually advise not to skim the board when tiling an area. From memory the rating almost doubles in regard to how much weight of tile the board can carry when it is not plastered as you get better adhesion of the tile adhesive direct to the board, particularly useful if you are using a stone tile or large format porcelain. Plus you save on money not plastering the area also .

I tell people this until I'm blue in the face. Builders just want to skim, fack knows why, maybe just about earning the price for meterage perhaps . Tiling directly onto PB is the better job, and, if part tiled, you can simply plaster to skim 'stop beads' a couple of hundred mm past the point that the tiles stop. 

[Ian]

7 hours ago, MrP said:

 

Just a heads up on the green pb, British Gypsum actually advise not to skim the board when tiling an area. From memory the rating almost doubles in regard to how much weight of tile the board can carry when it is not plastered as you get better adhesion of the tile adhesive direct to the board, particularly useful if you are using a stone tile or large format porcelain. Plus you save on money not plastering the area also .

@MrP

the reason that you're not supposed to tile onto plaster skim or onto normal plasterboard in a shower is that gypsum plaster is hygroscopic. Over time as cracks develop in the tile joints and water gets through the plaster will swell & fall apart.

Edited April 3, 2017 by Ian

[Nickfromwales]

7 hours ago, Ian said:

@MrP

the reason that you're not supposed to tile onto plaster skim or onto normal plasterboard in a shower is that gypsum plaster is hygroscopic. Over time as cracks develop in the tile joints and water gets through the plaster will swell & fall apart.

And the reason to never use acrylic ( aka ready made ) adhesive in anything resembling a wet area. 

And yet another good reason to tank wet areas. 

15 hours ago, jack said:

I was talked out of tanking as being "overkill".  The point was made that if water got through the tiles, it would find a way past the tanking under the shower tray and then have nowhere to go.

 

A good time to bump this thread. 

 

[Bitpipe]

1 hour ago, Nickfromwales said:

And the reason to never use acrylic ( aka ready made ) adhesive in anything resembling a wet area. 

And yet another good reason to tank wet areas. 

 

A good time to bump this thread. 

 

 While I may have erred on the skimming, we tanked the crap out of the bathrooms following Nick's guidelines on installing shower trays etc.

 

Also went full Impey on the wet room floor.

[jack]

@Nickfromwales, in answer to your question on the other thread, we haven't had problems anywhere else.  Maybe 5-10 spots over the whole house where screwheads have popped the overlying skim.  There are some fine cracks in the odd corner, and a more significant one where one section of ceiling skim joins another due to it not being possible to skim the whole ceiling in one go (long story - the guy doing the skimming was different to the ones who did the boarding - for the most part he did an excellent job).

Certainly no bowing or significant cracking that I can see.  That said, the internal walls are either double boarded with 12.5mm plasterboard, or have a single layer of 12.5mm Fermacell where we expected things might need to be hung (eg, TV), so not the same as the bathrooms.

[Nickfromwales]

Praise the lord then, ( if such an entity exists of course ? ).