I've been advised on here I need a 10mm half moon adhesive trowel to lay my 610mm x 405mm 12mm thick travertine on the plasterboard walls and marine ply floor but I'm a little confused how the size is measured is it the depth of the notch or the width of the that relates to the size. If its the width it will mean a 10mm halfmoons notches are only 5mm deep which I'm not sure will be ok for my floor as its a bit uneven.

They are very big tiles for walls what do they weigh? My 10mm round trowel is 10 mm deep, it will leave lines of 10mm on the wall or floor. Are you thinking of sticking the trav straight onto the ply?

Originally Posted by diamondtiling

They are very big tiles for walls what do they weigh? My 10mm round trowel is 10 mm deep, it will leave lines of 10mm on the wall or floor. Are you thinking of sticking the trav straight onto the ply?

So a 10mm trowels notches are 20mm wide please confirm. To add to the confusion more I've just been to wickes and they have a trowel with these dimensions but the description says 20mm round notch floor trowel.

Yep they are heavy at 6kgs each but there are only 4 per sqM and with the added weight of the adhesive and grout which I doubt will weigh 8kgs should be well within the 32kgs allowed for bare plasterboard.

I was going To lay Trav straight onto ply but someone mentioned sticking down some sort of membrane to avoid cracking is this absolutly neccessary as the floor is rock solid after all the strengthening I've done. The only problem is its a little uneven in places but I thought thats why a 10mm trowel is used..

have a look at tradetiler, they will be able to help you with your choices, I would be wary about the trav on a ply floor, deflection may be an issue, have you considered 6mm backer boards over the top?

Tradetiler Tiling Marshalltown Trowels

Originally Posted by diamondtiling

have a look at tradetiler, they will be able to help you with your choices, I would be wary about the trav on a ply floor, deflection may be an issue, have you considered 6mm backer boards over the top?

Tradetiler Tiling Marshalltown Trowels

I wanted to keep the floor as low as possible once its tiled because I dont want a step so I have used 18mm marine ply with loads of extra noggins spanning the 8"x 3" joists, believe me it felt solid when I jumped up and down on it.

Originally Posted by ohhnoo

I wanted to keep the floor as low as possible once its tiled because I dont want a step so I have used 18mm marine ply with loads of extra noggins spanning the 8"x 3" joists, believe me it felt solid when I jumped up and down on it.

that should be fine

Originally Posted by ohhnoo

I've been advised on here I need a 10mm half moon adhesive trowel to lay my 610mm x 405mm 12mm thick travertine on the plasterboard walls and marine ply floor but I'm a little confused how the size is measured is it the depth of the notch or the width of the that relates to the size. If its the width it will mean a 10mm halfmoons notches are only 5mm deep which I'm not sure will be ok for my floor as its a bit uneven.

don’t worry about the dimensions - just go and ask for / buy a 'thick bed solid bed trowel' it will have the right half moons for you. Buy a Rubi or BAL trowel, defo not Genesis (they are sharp, and very poor quality, even the spot welds suck).

The thick bed solid bed will deliver a min of 3mm solid bed of addy to your floor. The equivalent is a 10mm notch and back butter, but just use the right trowel, it will cost you less than £15 and guarantee 100% coverage (which you need to support soft trav especially on wood or with ufh) if you use it correctly.

As its trav and as its floor you need to fill / skim the cavities in the back of each tile before you put it down, or the filler / gap will burst through when you get floor traffic.


You are largish format so put a straight edge over your floor, it has to be spot on or you will get lippage. (even make sure all your screws are subflush!)

For your walls – the size of your tile doesn’t matter – the thickness does! If you are over 9.5mm thick I think you are at 32kg a square m. Its on the limit for dry lining but ok (do not have the dry lining skimmed or then they wont hold the weight), if it thicker (ie heavier) put up backer board. For your walls you may find a 10mm square notch easier to use but you must back butter the tiles. Id still stick to the thick bed solid bed trowel for the floor though.
I have the full boring details on my website here … Fareham tiler - tiling on Walls

double post (how do i delete a message Dan? thx)