Floor levelling

[AP Tiling]

I'm laying a kitchen floor with Green slate and the floor isn't perfectly level. There is one specific area where it is about 5mm out.

Will i be ok laying the slate and levelling with adhesive or am i better using a levelling compound before i start.

Thanks

[grumpygrouter]

Hello mate, 5mm isn't too bad though outside of BS recommendations. I have never laid slate yet and I know "it" is probably not flat so don't know if levelling would really solve the problem.

I think most of the more experienced guys on here would recommend that BAL PTB flexible be used for this type of installation but I understand it can be a little tricky if you haven't used it before. It can be used in a bed up to 25mm so would easily fill your problem area.

Have a look at this data sheet from BAL:

http://194.223.92.131/pdf/Technical%...B_Flexible.pdf

Grumpy

[Dave]

that amount of tolerance on the floor will be fine when working with slate..use a deep notch trowel and back butter the tiles to get them flat.....post us some pics in the gallery when done...http://www.tilersforums.co.uk/tilegallery/

i like green slate it looks well when down and sealed....

[AP Tiling]

Thanks for the quick replies.

The actual surface is pretty level, its just one end of the floor when i lay the level i can 'see-saw' it, think it may be over 5mm . Its that area im concerned about, its more of a lip in the concrete i think (only had a brief look at it).

The are of the ridge is in the walkway of the kitchen and im worried about potential damage to the slate.

[Leatherface]

If you can stand the cost of the self leveller and time it would always be better to self level.
This way you start with a level playing field. and will use less adhesive and spend less time bedding out than isf you had not self levelled.
Grade the slate first into 3 diff thicknesses .. Thick Med & thin. Start with thickest first, then med, then thin. Bedding up as you go. Back butter as required.
Chip off any unsighty corners and edges with a hammer and chisel.

[Ric]

only laid slate once and put thinnest one around edges of room where least traffic will be....