Preparation Advice needed - poor tiling job, dot and dab not to BS5385

Discuss Advice needed - poor tiling job, dot and dab not to BS5385 in the Tiling Forum area at TilersForums.co.uk

Soso

Active Member
We recently had a bathroom fitting in who said he used dot and dab to fix tiles to the wall and in the shower areas and also stated that any gaps behind tiles e.g. Mosaics would get filled in by grout so it would be fine. We can however hear what we think are some voids behind the large format tiles.

We have challenged him with info from tile association and what we know of British standards but he has now said (to counter our argument against dot and dab) he "back buttered" and this is recommended. He also stated "the skill of the installer is paramount".

We also challenged him and said that the shower area should have been waterproofed. He said it was unnecessary and now is saying water resistant adhesive and grout is enough. We don't believe this is the case according to tile association but don't know re British standards. Also is a domestic shower classed as a "wet area"?

He also said the British standards can't take into account "differing situations that may be encountered in different properties " but surely a standard house and bathroom installation shouldn't cause so many issues and should still be covered by what is stipulated in Brit standards ?

Lastly he has said there is no excess lippage as per bsi recommendations. Does anyone know the recommendations and how we can check them? We know there are some significant dips in the mosaic especially at the edges next to large format tiles...

Any advice greatly received. The tiler has accused us of picking out our own grout and has lied throughout our comms with him. It's heading towards full on dispute :-(
 

Andy Allen

Metro specialist & forum entertainer!
Trusted Advisor
Professional Tiler
JOTM Winner
Dot and dab method of tiling is wrong especially if there are voids behind the tiles....
There's no excuse for it and it should be all replaced and done properly.
 

Paul C.

Trusted Advisor
Professional Tiler
We recently had a bathroom fitting in who said he used dot and dab to fix tiles to the wall and in the shower areas and also stated that any gaps behind tiles e.g. Mosaics would get filled in by grout so it would be fine. We can however hear what we think are some voids behind the large format tiles.

We have challenged him with info from tile association and what we know of British standards but he has now said (to counter our argument against dot and dab) he "back buttered" and this is recommended. He also stated "the skill of the installer is paramount".

We also challenged him and said that the shower area should have been waterproofed. He said it was unnecessary and now is saying water resistant adhesive and grout is enough. We don't believe this is the case according to tile association but don't know re British standards. Also is a domestic shower classed as a "wet area"?

He also said the British standards can't take into account "differing situations that may be encountered in different properties " but surely a standard house and bathroom installation shouldn't cause so many issues and should still be covered by what is stipulated in Brit standards ?

Lastly he has said there is no excess lippage as per bsi recommendations. Does anyone know the recommendations and how we can check them? We know there are some significant dips in the mosaic especially at the edges next to large format tiles...

Any advice greatly received. The tiler has accused us of picking out our own grout and has lied throughout our comms with him. It's heading towards full on dispute :-(
Wow.... sounds like he is proper on the defensive.....

As far as I am aware, British Standards don't use exact words saying that spot fixing or dottin' and dabbin' is wrong. However it does say that the tiler should achieve as close to full coverage as possible, which most spot fixing will not do, whatever anyone says.

If he is back buttering and applying more spots of adhesive on top, he is wasting his time as most of the back spread of adhesive is now elevated from making contact with the substrate and still leaving voids.

A "wet area" is anywhere of regular/intermittent contact with water or steam. Adhesive and grout being water resistant is fine providing the coverage is solid (no voids) and compressed sufficiently when fixing as this will drastically reduce the flow of water from making contact with the substrate in such quantities that would potentially cause a problem. Again, spot fixing allows free movement of water which can saturate all contacting adhesive and reducing the already limited bond strength.

Lippage is specific in BS. no more than 1mm on joints less than 6mm, 2mm allowance on joints 6mm and over. This is dependant on the tile so if it is rustic or bowed it may not be possible and BS would still allow it. If the tile however is perfectly flat with minimal to no surface texture, he has no excuse. Fixing thinner mosaics against thicker tiles is difficult, but not impossible if he knows what he is doing. There are ways of leaving a solid coverage and small notches for the mosaic to press into. But I have never had to do it so would be better if someone with more experience can advise you better on that one.

Alot of "old school" tilers say that tiles need spot fixing to allow better adjustment over uneven surfaces. Good modern tilers will spread the adhesive on the wall and back spread the tile with a variety of different trowels (trial and error) to get the correct level AND full coverage.
 
OP
S

Soso

Active Member
Wow.... sounds like he is proper on the defensive.....

As far as I am aware, British Standards don't use exact words saying that spot fixing or dottin' and dabbin' is wrong. However it does say that the tiler should achieve as close to full coverage as possible, which most spot fixing will not do, whatever anyone says.

If he is back buttering and applying more spots of adhesive on top, he is wasting his time as most of the back spread of adhesive is now elevated from making contact with the substrate and still leaving voids.

A "wet area" is anywhere of regular/intermittent contact with water or steam. Adhesive and grout being water resistant is fine providing the coverage is solid (no voids) and compressed sufficiently when fixing as this will drastically reduce the flow of water from making contact with the substrate in such quantities that would potentially cause a problem. Again, spot fixing allows free movement of water which can saturate all contacting adhesive and reducing the already limited bond strength.

Lippage is specific in BS. no more than 1mm on joints less than 6mm, 2mm allowance on joints 6mm and over. This is dependant on the tile so if it is rustic or bowed it may not be possible and BS would still allow it. If the tile however is perfectly flat with minimal to no surface texture, he has no excuse. Fixing thinner mosaics against thicker tiles is difficult, but not impossible if he knows what he is doing. There are ways of leaving a solid coverage and small notches for the mosaic to press into. But I have never had to do it so would be better if someone with more experience can advise you better on that one.

Alot of "old school" tilers say that tiles need spot fixing to allow better adjustment over uneven surfaces. Good modern tilers will spread the adhesive on the wall and back spread the tile with a variety of different trowels (trial and error) to get the correct level AND full coverage.
He has definitely gone off and read some of the British standards to try and mitigate anything we might say is wrong but looks like he has misquoted some of it. Does the British standard say anything about it being essential to waterproof regardless of water resistant grout and adhesive being used ? This is what the tile association told us anyway.
 

Andy Allen

Metro specialist & forum entertainer!
Trusted Advisor
Professional Tiler
JOTM Winner
Waterproofing or tanking a shower area is not a regulatory practice as it is in other countries, it is always recommended but at the tilers / customers discretion..
 

Paul C.

Trusted Advisor
Professional Tiler
BS5385 part 4:2015:

7.2.3 Installations not immersed but subject to occasional wetting.
In installations where contact with water is only intermittent, and the installation has had the opportunity to dry out between periods of use, e.g. domestic (not power) showers, 7.2.1 and the following should apply: (have checked 7.2.1 and all it says relating to your query may be not to use plaster or gypsum based materials in wet areas as they are unstable when wet or when combined with cement based materials).

a) The background should preferably be cement and sand rendering or dense concrete. Sheets and boards should not be used unless they are dimensionally stable in changing moisture conditions. Tiles should be solidly bedded in water resistant adhesive.

b) The joints between the tiles should be water-resistant but additional protection can be obtained by using an impervious grout.

c) The gaps between wall and shower tray/bath should be sealed, particularly where the installation is located on a suspended floor.

NOTE 1, for water sensitive backgrounds e.g. gypsum plaster, additional protection in the form of a waterproofing tanking system may be considered.

NOTE 2, The use of impervious grouts and adhesives is no substitute for a tanked installation.

More to follow when I get a bit more time.... 7.2.4 which is for wetrooms and domestic power showers. or you can have a browse yourself:
British Standards no longer available at Newcastle Library.... But here's another way. - https://www.tilersforums.co.uk/threads/british-standards-no-longer-available-at-newcastle-library-but-heres-another-way.83947/
 

MissTiler

TTA Tile Fixer of the year winner 2017
Trusted Advisor
Professional Tiler
TTA Member
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The Standards regarding Tanking in domestic situations was changed recently.
 
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