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**guy1976** · 01-09-2007

how thick did you apply the adhesive to the back of tile?

GazTech · 01-09-2007

[quote=sriel1;23682]Yeah the tiles were dot and dabbed onto the wall.

Ive taken a sample loose tile off the wall and all the adhesive is connected to the tile, which covers more than 3/4 of the tile.

Tiles were 400x600mm porcelain, approx 5mm depth...[/quote]Firstly the adhesive has to be suitable for porcelain ie acrylic...it should not be dotted out,especially if the walls have not been primed,usually a layer of dust prevents good contact,after a short while the tiles will de-bond from the plaster...grout will shake and the tiles will come off....Can you tell us the products you used on this job ? ..Gaz

sriel1 · 01-09-2007

Granfix 1part flexible rapid set.

Walls were adequately primed before tiling.
After removing a loose tile I checked the wall where contact wasnt made with the adhesive and it was still primed effectively.

Like i said earlier there was more then 75% coverage of the tile.
Tiles werent studded or have rough back on them.

Granfix recommendations were to apply between 3 and 6mm bed, this was approx 5mm thickness...

Has anyone seen BS5385?
Do you think it would be useful at all?

GazTech · 01-09-2007

see if this helps...Gaz...[url=http://www.tiles.org.uk/help/answer-food.shtml]Food Preparation[/url]

sriel1 · 01-09-2007

Thanks Gaz,

Ive had a look through the TTA website and made note of all references to 5385 and this page is one of the most useful.

Still I need more info about BS5385-1, what is the minimum area coverage between tile and wall, how thick bed adhesive on uneven walls, acceptable methods of applying adhesive.

Any help is always appreciated
Thanks again

**grumpygrouter** · 01-09-2007

I was taught never to dot & dab adhesive..................

01-09-2007

BS5385-1.

Application of adhesive and tiles.

Thickness of adhesive - manufacturers instructions should be observed.

For situations where dry conditions will prevail after tiling is completed the notched trowlling method should be used. The adhesive should be applied to the surface as a floated coat with a trowel which should then be combed through with a notched trowel of the type recommended by the adhesive manufacturer. This will give a series of ribs into which the dry tiles should be pressed with a twisting or sliding action. This action 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.

**Dave** · 01-09-2007

50% coverage is ok for dry areas but for situations where wet or intermittently wet or prolonged damp conditions prevail after tiling is completed/ full coverage of adhesive,as far as practically possible,with the back of the tile and background should be acheived...backbuttering of the tile will help with this process............dave..

**Varley** · 01-09-2007

Quote:

Originally Posted by sriel1

Yeah the tiles were dot and dabbed onto the wall.

Ive taken a sample loose tile off the wall and all the adhesive is connected to the tile, which covers more than 3/4 of the tile.

Tiles were 400x600mm porcelain, approx 5mm depth...

If they are only 5mm thick then weight certainly is not an issue.

Was there any reason you dot and dabbed the tiles onto the wall as opposed to trowelling out?

01-09-2007

Quote:

Originally Posted by dhceramics

50% coverage is ok for dry areas but for situations where wet or intermittently wet or prolonged damp conditions prevail after tiling is completed/ full coverage of adhesive,as far as practically possible,with the back of the tile and background should be acheived...backbuttering of the tile will help with this process............dave..

Was just looking for that bit. The crafty so and so's have put it in part 4!!.

I think the key thing for the query is that dot and dab is not mentioned in BS5385. It's either notched trowel method for dry areas or solidly bedded for wet/damp areas.

**Varley** · 01-09-2007

Quote:

Originally Posted by McP77

Was just looking for that bit. The crafty so and so's have put it in part 4!!.

I think the key thing for the query is that dot and dab is not mentioned in BS5385. It's either notched trowel method for dry areas or solidly bedded for wet/damp areas.

I didn't think it was, dot and dabbing tiles is not a good method, too many gaps left between walls and tiles, very prone to cracking when attempting to drill through is one of the major problems.

sriel1 · 01-09-2007

Thanks everyone, thats really useful.

So British Standards suggests that all bathroom walls are notched trowelled and the tiles are buttered. And bed thickness is down to the adhesive manufacturers.

The walls I tiles were really uneven and the tiles were laid out brick fashion - hence why I used dot n dab. Tiled other bathrooms the same way in the same property and theyre perfect.

Only the grout was stopping the tiles from dropping off. All the adhesive had stuck to the tile and taking the adhesive off the tile didnt require much effort at all.

Do you think dot and dab might be directly responsible for this?