Notches or all solid bed?

[Realstokebloke]

Following on...I have ensuite floor (330mm sq ceramics on 6mm hardibacker - so flat & even - with BAL single part fast flex) so what notch trowel do I need plse? I assume a 10mm notch? Or bigger?Shower Walls - on 10mm Hydrapanel (Marley Eternit) using BAL single part Flexible, is this a notch or a solid bed on walls plse? If notch 6 or 10mm plse?Other walls (plasterboard - currently painted so I assume I need to get paint off & prime & use same addy as shower walls but here, as it's outwith the shower (wet) area is it a noitched trowel - 6 or 10 mm plse?Many thanks.RSB

 

[Andy Allen]

i would go 10mm round notch for the walls and floor.

remove paint and prime using the adhesive manufactures recommendation.

 

[White Room]

Could back skim the tiles as well..

 

[Realstokebloke]

My "floor" trowel is a 20mm - won't that do? (I assume a 20 gives a thicker bed overal when compressed, so isn't that a good thing?)Thanks.

 

[bobbynz]

20mm!!! show off!rrr:
Well go on then, show us your trowel :yikes:

 

[Realstokebloke]

Trowel envy over there bobby? I just don't get "notch sizes" - logically, I assume the size of the notch equates to the depth of the bed underneath when the tile is compressed / bedded down?So a 10mm notch = a 10mm bed & so on ?Is that right?Will I actually be OK with a 20mm (round) for floors & walls? Cheers.

 

[bobbynz]

If you use the 20mm then you will use twice as much adhesive than you need to and cost you more. Depending on the adhesive you use and the temperture the setting time will be longer so it wont improve things if you use the 20 you would be better off using an 8 and a 10 for the floor imo. More is sometimes not always good.
Adhesives used today are normally a thinset adhesive. Some will not be suitable for such a heavy bed. 2 to 5mm bed is sufficient once the tile has been bedded into it as long as you have almost 100 percent coverage to the back of the tile and as its already been mentioned, back buttering wouldn't hurt either.
Ardex for instance recommend a 6mm for walls and a 10mm for floors. The notches allow you to set the tile well into the adhesive as it sets in, the adhesive will flatten out the notches to form good coverage to the back of the tile. Back buttering the tile will give it an excellent bond to adhesive you spread onto the wall or floor. hope thats helpful and happy tiling:8: