Confused by trowel notch sizes.

[agwill]

Hope someone can help me? I have received a floor tiling job to quote for which specifies Mapei adhesive and grout (Keraflex and Ultra colour). On the data sheet it says to use an n.5 notched trowel on mid size floor tiles and an n.6 on larger sizes. What size is an n.5 in mm? The spec says to use a 3mm solid bed. This seems rather thin to me?:huh2:

 

[brian c]

welcome to the forums m8,as long as you use a suitable notched trowel that provides a thickness of 3 to 6 mm you will be fine.sometimes you need to back butter large tiles to ensure a solid bed.

 

[tilermandan]

dont worry about the spec to much in this case. i use an 8mm square notch on walls and a 10mm square notch on floors these i find are adequate for most jobs, but always check coverage randomly as tiling. you will need to make sure you are achieving no less than 65% coverage on walls and 100% on floors hope this helps.

 

[DHTiling]

dont worry about the spec to much in this case. i use an 8mm square notch on walls and a 10mm square notch on floors these i find are adequate for most jobs, but always check coverage randomly as tiling. you will need to make sure you are achieving no less than 65% coverage on walls and 100% on floors hope this helps.

Also if its showers or wetrooms then 100% on walls as well....

 

[tiler burden]

hi

its strange that alot of people use 10mm notched for floors, when many people claim you need a 10mm half round to achieve 100 perc coverage.

dont get me wrong, i am not critising anybody, it just gets confusing at times?

i was told 3mm for mosaics, 6mm/8mm notched for walls and 10mm radius trowel for floor tiling, and naturals on walls as well as back buttering.

makes you wonder why theres a 10mm and 12mm notched, if all of the above do the same job....

ed

 

[tilermandan]

10mm square notch 10mm half round the bed depth and coverage
is still the same surely? i think i gos down to preference at the end of the day really.six of one and all that!

 

[tiler burden]

no mate,

apparently the half round gives 100 percent and i think the notched achieves 70-80....if i am wrong please feel free anybody to correct me as i dont want to give out the wrong info

ed

 

[DHTiling]

Hi ed mate..

Just to clarify this for you mate....

Larger notch trowels are used with large format tiles and un-even substrates etc...but you will need to use thick bed adhesives as well...other wise the adhesives cant cope with the bed thickness... wot i mean by thick bed adhesives is these are the type which won,t shrink or slump whilst drying....i.e. BAL PTB...etc etc....there are other makes but this is just an example...

hope this helps... ..

BAL PTB (Pourable Thick Bed) Flexible

A highly polymer modified, flexible, rapid-setting, water-resistant, frost-resistant floor tile adhesive, especially suitable for fixing tiles, including fully vitrified and porcelain tiles to low porosity backgrounds and bases. Sulphate-resistant, cement-based, pourable, thick-bed solid-bed floor tile adhesive suitable for fixing ceramic tiles, quarries, natural stone and terrazzo in interior and exterior situations. Its consistency makes it particularly suitable for fixing large tiles and those with profiled backs. Back-buttering is not necessary. Suitable for use on concrete, cement:sand screeds, ceramic/quarry tile/terrazzo/hard natural stone, plywood overlay, vinyl tiles/sheet, mastic asphalt. BS EN 12004 C2F Adhesive

 

[tilermandan]

there is no wrong info mate.its all good advice your giving thanks for your input on the thread,at the end of the day i think your safe with either.

 

[tiler burden]

thanks for that dave ;0)

much appreciated as always. you can see where i am coming from with the confusion tho mate. you get so many people saying 10mm half round and even 20mm half round for larger heavy stones because they achieve 100 per etc etc, then some people say 10mm 12 mm but yet they apparently dont achieve 100 perc]

i'll stop waffling on now and go and see iif the wife is ready to give birth yet! on standby waiting for baby no 3!!!!!

cheers
ed

pps thanks to tilemandan, appreciate your advice too mate, all the best ;0)

 

[DHTiling]

If you want more coverage than 70% coverage then you need to use a solid bed trowel.....
A solid bed trowel is one that has notches that are deeper than they are wide...
thus when the tile is pressed into the bed it will spread out and create a solid fix....

hope this helps edd.....

 

[Perry]

if any of you find any trowel that i can put tiles straight on the floor with 100 % coverage let know please i use 13mm trowels put tile down pick tile up put more adhesive under tile put tile down, square half round oblong triangular whatever , every situation is different every tile is different every floor is different if only it was that easyete

 

[DHTiling]

wow..wow...stuff the trowel sizes edd..........

let us know wot she has mate......we will be waiting.....

 

[tiler burden]

hi dave

i know what we are having already..a boy!! we have 2 boys already and i think the wife secretly wanted a girl, so the she asked the nurse at the scan, what the sex was...dont get me wong, she is over the moon with another boy but its a problem for me as i'll have to keep going till we have a girl. i'm 39 next month so the clock is ticking!!!!!!!

ed

 

[Perry]

good luck ed keep going mate i have 5 boys 2 girls its good fun trying he he ete

 

[tiler burden]

JESUS PETE!!!

IN WHAT ORDER DID THE KIDS COME..SODS LAW WE'LL HAVE 4 BOYS BEFORE A GIRL.

we are off to australia to live end of the year begining of 2009 and we dont have any parents or family to rely on, so my wife in her wisdom has decided to create a mafia to look after us when we are old lol

but you right about the trying bit tho ;0)

ed

 

[brian c]

good luck ED,all the best bud.

 

[agwill]

Thanks to all for the advise. I'm still a little confused by the size though. Should I ignore the spec and data sheet? Will 10mm notches/half-round produce approximately a 5-6mm final bed thickness?
Thanks again for all your time.

 

[Pawelzik]

Hello agwill & welcome to the forums. As we have all the same technics and facing the same problems but having different national rules I show you wich notch sizes are to preferably ro be taken in Germany:
Tile lenght up to 50 mm -> Notch trowel 3x3x3 mm*
Tile length 50 - 108 mm -> Notch trowel 4x4x4 mm*
Tile length 108 - 200 mm -> Notch trowel 6x6x6 mm*
Tile length over 200 mm -> Notch trowel 8x8x8 mm*
Tile length over 300 mm -> Notch trowel 10x10x10 mm or half round 10 mm or half round 12 mm**
* As a rule
** As a recommendation
Greetings from north Germany, Martin

 

[tiler burden]

many thanks pawelzik,

your help is very much appreciated ;0)

ed
----
do we have any similar guides lines in the uk? or is there any bs standards literature out there that gives recommended guide lines for trowel depth / regarding tiles size?? i totally appreciate that its not the tile sixe alone that determines the trowel size but its a good guide line to go off

 

[grumpygrouter]

I think I remember vaguely seeing a post that said as a rough guide that the notch size should be about the same as the thickness of the tile, but I may be wrong.

Grumpy

 

[Pawelzik]

many thanks pawelzik,

your help is very much appreciated ;0)

ed
----
do we have any similar guides lines in the uk? or is there any bs standards literature out there that gives recommended guide lines for trowel depth / regarding tiles size?? i totally appreciate that its not the tile sixe alone that determines the trowel size but its a good guide line to go off

Hello Ed. Sorry, I have checked via Google if there is any rule for the UK regarding taking which notch trowel for what. I only find recommendations and mostly refering to several different adhesives and other construction mortars.

May be it is hidden / written somewhere in the BS 5385 but I can´t find as this BS is dvided into several parts which I can´t search all resp. take a look at. I think the easiest will be to ask one of the course teachers from the training center where you have been.

 

[m4ubs]

What if you use the deeper 15mm U shaped notched trowel on floors....isn't that guaranteed to give 75-100% coverage ? Just one stroke of the trowel and start laying....

 

[grumpygrouter]

What if you use the deeper 15mm U shaped notched trowel on floors....isn't that guaranteed to give 75-100% coverage ? Just one stroke of the trowel and start laying....

Thats the general idea of U notch trowels. Would still check that you get the coverage though by lifting the occasional tile.

Grumpy

 

[Fekin]

No wonder many slackers just dot n dab :lol:

 

[devonmark]

No wonder many slackers just dot n dab :lol:

LOL....

 

[m4ubs]

Does anybody actually use a 15mm deep floor trowel ? How does it compare ?Usually they sell 12mm for floors in stores like BnQ and Focus.

 

[DS Tiling]

We use 15mm U notch for mid/larger floor tiles but as dave says with a PTB addy to accomodate the thicker bed. I find they give good coverage and often eliminate the requirement for back buttering and also gives more to play with if you have to level them. Downside is they eat addy and I'm sure we have lost jobs by specifying with them. Customers just want tiles looking good and cheaply laid and aren't concerned that their new floor is full of hollows where there is no addy contact but such is life.

 

[mz30]

In my experience,if your tiling a floor the state of the floor will dictate the thickness of the serrator you use ,why use all that adhesive when it's not required?

If my memory is correct british standard's require 75% coverage(that may have changed).
As for back buttering goes if a floor or wall require's it i will not touch it,tiles are meant to be set in an even bed not built up to suit.
Back buttering creates hollow's and also create's mess.

Just to add i have never used a 15mm notch and would never use one,i have a lot of experience using porcelonsa tile's 1000mm x350mm on wall's and the spec state's to use between a 6mm and 8mm notched trowel(if memory serve's me right)

 

[howard]

I always use a 12mm trowel on floors i find there is no need to back butter even if the floor is slightly out