Trowel size for 22mm sandstone flags

[M1d1]

Hi,
I am unsure what size trowel to use for the flagstone I have to lay in the hallway. They are 'calibrated' to around 22mm, going to be laid on benfer leaderflex, The substrate is the old tiles which are set in concrete and will be primed for the new adhesive. It is very level and good to go. What trowel would you suggest?

 

[Dumbo]

What sort of size are they width and length .

 

[M1d1]

Hi
They are as follows
900 x 600
600 x 600
600 x 300

 

[Spare Tool]

Laid similar last week..12mm trowel and back skim every piece

 

[M1d1]

Thanks for the information, so going on a 12mm notched with the adhesive spread in the opposite direction on the stone.
Is there any advantage or disadvantage to using a half round trowel for this?

 

[Spare Tool]

12mm on the floor then use the flat edge of the trowel to skim the backs of the stone. You will find although it says the stone is calibrated the backs will not be flat, skimming the back not only gives better adhesion it also fills any voids and dips in the backs of the pavers..
I use a square notch but shouldn't really make much difference.
Good luck

 

[M1d1]

I'm thinking about 10 or 12mm for the grout.
Which sealer would you recommend?

 

[Spare Tool]

Tend to use lithofin stainstop for more or less everything.
Didn't use spacers just rack of eye but joints were probably about 10mm give or take

 

[Spare Tool]

 

[M1d1]

Looks very similar to what is going down. What grout did you use, I have a buff coloured brush in type. Or should I save that for outside and use normal gear?

 

[Spare Tool]

That's ultra grey, looks a bit dark cuz had only just given it a final seal, I actually took the time to mask every joint before grouting, quick tickle over with the sponge then removed masking tape and didn't touch it again. Saved a lot of wash up time and left joints nice and full

 

[Spare Tool]

 

[M1d1]

Ha, I would so mess that up. Did you seal the stone before grouting or do it all together at the end?

 

[Spare Tool]

Sealed twice before grouting then once after. Soaks up sealer like a sponge