Tiling Standards (BS 5385) | British Wall and Floor Tiling Standards - IN FULL

[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Think your 50% spread is also out of date: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 ?