Important Changes to Tiling Standards

[Time's Ran Out]

Ask the client how to set the room out!
That’s why they are paying you - to do a professional job.
Clients away on holiday, that’s okay I’ll send him a photo of how it’s going to look - he’s going to be really confident in your ability.
What’s been done is sh*te and these chancers do our trade no favours.

 

[acaciaguy]

I agree John. I advise clients on what I wil do and look best. However they are the ones that have to look at it forever. If they are happy i am

To avoid any conflation of posts. I agree John the work op posted is rubbish

 

[peterwhayward]

I would say that almost all of my bathroom jobs have a cut or trimmed tile at the bath ( or shower tray)to avoid that awful finish at ceiling level or anywhere else.

 

[Soso]

Hello all,

I have a query regarding the British standards. I note that they say the following below about notched towelling method. What is confusing me is the bit about 50% contact. Surely this is 50% while its being placed on the wall but that the twisting and sliding action should result in 100% coverage ? I have a builder trying to justify dot and dab based on this wording. Or trying to justify not covering the whole tile.

Also, can i also assume that 50% contact still means that 100% of the wall should be covered in adhesive...the 50% is just the ribs sticking out of the adhesive from trowelling?

Second question is that i just need to be able to explain the difference between back buttering and dot and dab in layman terms for a judge. Can anyone help me ?

Notched trowelling method
Adhesives should be applied to the background with a trowel as a floated coat, the adhesive should be pressed into the surface, and combed through with a suitably designed notched trowel of the type recommended by the adhesive manufacturer: this gives a series of ribs into which the dry tiles should be pressed with a twisting or sliding action; this operation has to be carried out correctly to ensure that the adhesive wets the back of the tile and achieves an area of contact of at least 50%, spread evenly over the back of the tile.
Whatever type of trowel is used, it should apply the adhesive
in a manner such that the finished bed thickness is no greater than that recommended by the manufacturer and that maximum practical contact between tile and adhesive is achieved.
The period of time during which tiles can be adequately bedded after spreading the adhesive is approximately 20 min but this varies according to the prevailing atmospheric conditions. It is important that more adhesive should not be spread on the wall than can be covered with tiles within the open time.
NOTE 1 The amount of adhesive used and the height of the ribs obtained are governed by the angle at which the trowel is held against the surface. The amount of contact is also dependent on the twisting or sliding of the tiles as they are pressed onto the ribs of adhesive.
NOTE 2 It is good practice to remove a tile occasionally as fixing proceeds to check that adequate contact and wetting is being maintained with the adhesive.

 

[Tile Shop]

BS5385 part 1, 2018
7.1.2 - Bedding materials:
blah blah....
Tiles should not be fixed using the dot and dab technique.

So important, they repeat it in 7.2.1.6 - Tile joints
Tiles should not be fixed using the dot and dab technique.

Think your 50% spread is also out of date:
6.2.3.1 - General
Tiles with a surface area of 0.1 m2, should be solidly bedded.
Tiles with a surface area of less than 0.1 m2, but which weigh more per square metre than 70% of the background's capacity to carry the weight, should be solidly bedded.

Your exact wording above from 7.2.1.5.1 Notched Trowelling method, "this operation has to be carried out correctly to ensure that the adhesive wets the back of the tile and achieves an area of contact of at least 50%, spread evenly over the back of the tile". - This sentence was removed in the last 2018 update.

So yeah, your builder is wrong! Sack him and get yourself someone who knows what they are doing.

 

[Dumbo]

Have you a failure or are worried about future failure .
But as above if he is still working stop him ..
What is the value of your work if it several thousand it may be worth getting a tta report on the work.

 

[Old Mod]

I’m so glad you saw this @Paul C.
I knew I’d seen this written somewhere, and was about to go hunting.

 

[Soso]

BS5385 part 1, 2018
7.1.2 - Bedding materials:
blah blah....
Tiles should not be fixed using the dot and dab technique.

So important, they repeat it in 7.2.1.6 - Tile joints
Tiles should not be fixed using the dot and dab technique.

Think your 50% spread is also out of date:
6.2.3.1 - General
Tiles with a surface area of 0.1 m2, should be solidly bedded.
Tiles with a surface area of less than 0.1 m2, but which weigh more per square metre than 70% of the background's capacity to carry the weight, should be solidly bedded.

Your exact wording above from 7.2.1.5.1 Notched Trowelling method, "this operation has to be carried out correctly to ensure that the adhesive wets the back of the tile and achieves an area of contact of at least 50%, spread evenly over the back of the tile". - This sentence was removed in the last 2018 update.

So yeah, your builder is wrong! Sack him and get yourself someone who knows what they are doing.

Believe it or not Paul, this builder is arguing that he did the work in May 2018 and therefore the June 2018 version of the text which came out in june itself doesn't apply and he wouldn't have known about it. So he is trying to warp what the sentence i the bsi 2009 version which is the 50% coverage....while happily ignoring the words (spread evenly on the back of the tile).

My assumption, and this is what i need help on a little is that this 50% is the ribs a notched trowel would create. The wall would be covered in adhesive too. And when the tile is pushed into the ribs, it will spread and cover 100% of the tile ?

 

[Tony_C]

Think of back buttering as you would butter toast, skimming a thin layer over it. Not dabbing 5 blobs

EDIT:

This isn't to replace serating the wall/floor. It's to help with better coverage also when setting the tile into the ribs. I should have added that

 

[Soso]

Think of back buttering as you would butter toast, skimming a thin layer over it. Not dabbing 5 blobs

OMG Tony, that is perfect !!! I hadn't even thought of it that way but that would make anyone understand !!! Thank you so so much

 

[Soso]

Have you a failure or are worried about future failure .
But as above if he is still working stop him ..
What is the value of your work if it several thousand it may be worth getting a tta report on the work.

Thanks jcrtiling. We are in court at the moment sadly. Been ongoing for a year and I think this person is likely to only stop all this if the TTA do a report - completely agree

 

[J Sid]

BS 5385-1:2009
7.2.1.5 Application of adhesive and tiles
7.2.1.5.1 Notched trowelling method For situations where dry conditions prevail after tiling is completed, the notched trowelling method should be used. The final bed thickness of the cement-based adhesive should not exceed 3 mm; if it is used at a thickness greater than this, excessive stresses might develop possibly resulting in cracking of the tiles and/or adhesion failure. The adhesive should be applied to the surface as a floated coat with a trowel, pressing the adhesive into the surface, to give a bed
thickness of approximately 3 mm, which should then be combed through with a notched trowel of the type recommended by the adhesive manufacturer: this gives a series of ribs into which the dry tiles should be pressed with a twisting or sliding action; this operation has to be carried out correctly to ensure that the adhesive wets the back of the tile and achieves an area of contact of at least 50%, spread evenly over the back of the tile. Tiles should be fixed before surface drying of the ribbed adhesive bed prevents the adhesive wetting the back of the tiles: the open time varies according to the prevailing atmospheric conditions and is usually about 20 min; it is important not to spread more adhesive on the wall than can be covered with tiles within the open time of the adhesive.
7.2.1.5.2 Buttering method The buttering method can be used for occasional awkward tiling positions, e.g. around openings and restricted areas where a notched trowel cannot be used; where this technique has to be adopted, the adhesive should be spread evenly over the whole of the back of each dry tile with a trowel. The bed thickness should be slightly greater than the final thickness required so that when each tile is pressed or tapped firmly into position the correct thickness is achieved. The thickness should not be greater than the maximum recommended by the manufacturer of the adhesive. Care should be taken to ensure that as far as possible no voids are left behind the tiles.
7.2.1.5.3 Notched trowelling and buttering method The notched trowelling and buttering method combines 7.2.1.5.1 and 7.2.1.5.2 and should be used for fixing large tiles (3.4) and tiles with ribbed, deep keyed or heavy buttoned back profiles. A thin coating of adhesive buttered over the backs should fill the deep keys before placing the tiles in position on the combed adhesive bed. There should be no significant increase in the bed thickness. NOTE This bedding method aims to achieve a solid bed

 

[Dumbo]

Other than the builder doing it wrong what are the problems that you actually have

 

[Tile Shop]

Sorry to bring this up late, but can we just clarify that this is a wall installation and not floor?

Also is it a wet or dry area?

 

[Soso]

BS 5385-1:2009
7.2.1.5 Application of adhesive and tiles
7.2.1.5.1 Notched trowelling method For situations where dry conditions prevail after tiling is completed, the notched trowelling method should be used. The final bed thickness of the cement-based adhesive should not exceed 3 mm; if it is used at a thickness greater than this, excessive stresses might develop possibly resulting in cracking of the tiles and/or adhesion failure. The adhesive should be applied to the surface as a floated coat with a trowel, pressing the adhesive into the surface, to give a bed
thickness of approximately 3 mm, which should then be combed through with a notched trowel of the type recommended by the adhesive manufacturer: this gives a series of ribs into which the dry tiles should be pressed with a twisting or sliding action; this operation has to be carried out correctly to ensure that the adhesive wets the back of the tile and achieves an area of contact of at least 50%, spread evenly over the back of the tile. Tiles should be fixed before surface drying of the ribbed adhesive bed prevents the adhesive wetting the back of the tiles: the open time varies according to the prevailing atmospheric conditions and is usually about 20 min; it is important not to spread more adhesive on the wall than can be covered with tiles within the open time of the adhesive.
7.2.1.5.2 Buttering method The buttering method can be used for occasional awkward tiling positions, e.g. around openings and restricted areas where a notched trowel cannot be used; where this technique has to be adopted, the adhesive should be spread evenly over the whole of the back of each dry tile with a trowel. The bed thickness should be slightly greater than the final thickness required so that when each tile is pressed or tapped firmly into position the correct thickness is achieved. The thickness should not be greater than the maximum recommended by the manufacturer of the adhesive. Care should be taken to ensure that as far as possible no voids are left behind the tiles.
7.2.1.5.3 Notched trowelling and buttering method The notched trowelling and buttering method combines 7.2.1.5.1 and 7.2.1.5.2 and should be used for fixing large tiles (3.4) and tiles with ribbed, deep keyed or heavy buttoned back profiles. A thin coating of adhesive buttered over the backs should fill the deep keys before placing the tiles in position on the combed adhesive bed. There should be no significant increase in the bed thickness. NOTE This bedding method aims to achieve a solid bed

Thank you Julian. I am hoping that the bit about "spread evenly over the back of the tile" and the fact that the entire wall needs to be covered in adhesive should be enough to bat this out. It's a shower area and there should be no voids and the areas should be solidly bedded which i believe part 4 of the standard also states. It's just that the 50% written here is mis-leading surely ?