Butter up underside of floor tiles?

[Lucas 2]

Generally, I find floor-tiling a bit harder than wall.
Does it help if you butter up the bottom of each tile as well as spread floor adhesive or is that only advisable with non-porous tiles like porcelain?
Also, does a trowel with round notches have advantages for floor..?

Thanks for you advice...

[whitebeam]

If the tiles have a profile on the back I back butter them or use 12-15mm spreader or both if it's a large one, tile that is

[batiling]

I tend to do this most of the time unless its a large area or really even floor.usually most floors are uneven so i find this easier and cleaner.i think its whatever you prefer

[rhyd4]

spread on the floor and backbutter where needed, if the floors good and your using the right trowel and a good mix i dont see the need.
a half curlce trowl is designed to give maximum coverage, my favourite for floors if good

[Eddie]

I usually find that, even if i start only spreading the floor, i always have to spread some of the tiles too.

[sranners]

i start with the floor and butter were i need to, unless im fixing stone that is dusty then i scim all tiles. I am going to start trying bigger trawls with thicker beds.

[whitebeam]

20mm is the biggest, I think

[pjc]

should always butter backs unless you use PTB :Pete

[Gazebo]

should always butter backs unless you use ptb ete

ptb.?.??????????????????/

[Dave Ramsden]

pourable thick bed

[R Montgomery]

I always skim the back of handmade tiles to even the surface,same with ribbed back tiles,large format tiles and stone.Sometimes and in some places the skim will turn into back-buttering.I find that this is a more accurate method,for gaining full coverage,than going to a larger notched trowel.You can easily adjust the thickness of the skim to take into account differences in the thickness of the tile.

[Lucas 2]

yeah I meant skim the underside not 'butter up' unless absolutely nec. as could get too much adhesive - my mate always skims the underside of floor tiles to get better adhesion......cheers for replies