External Porcelain Tiles - Advice please

Discussion in 'Tilers' Talk' started by Dmck, Jun 19, 2018.

  1. Dmck

    Dmck New Member

    Hey folks I am looking for some advice for a DIY job I am thinking of attempting. I have never done any tiling before so I would like to give it a try. Small area about 1.5m square.

    My outdoor porch is currently tiled but the tiles are about 30 years old and have started to fall off. I am thinking of replacing them and any advice would be appreciated. The existing tiles are on a concrete slab, and there appears to be a rubber mat layer between the concrete and tiles, I'm assuming its a waterproofing membrane but not sure.

    I was advised to use porcelain tiles and I expect I will need to remove all of the old tiles and their adhesive cement. Is it OK to leave some of the old cement or can it be a bit rough?

    How do I prep the surface after removal of the old tiles? Do I need leveling compound? Do I need some sort of waterproofing membrane? any advice on what adhesive or grout to use.

    I intend to do a dry run with the tiles before getting stuck in. I've also read that I should butter the back of the tile and spread a layer of adhesive on the concrete surface I am applying the tile to....is this overkill?

    Thanks
     
  2. DIYDave.

    DIYDave. Well-Known Member

    Ello there...

    I’m only diy me but have done a fair bit of tiling (various areas) and recently tiled a similiar sounding porch floor

    Ok, in theory, IF, the current tiles were fully bonded to floor and no hollow and/or loose tiles, then yep, after degreasing and sealing tiles, you could tile back over

    But, in this case, several have come loose so gotta bite the bullet and pull em all up. Ur be wasting ur time and effort otherwise

    Question is why have tiles failed and are falling off ?

    Either poorly laid in the first place (but they’ve possibly been down for decades), or maybe some damp coming up through slab ?

    Once you lift tiles, if damp, you will probably notice the smell

    So anyway, lift tiles, try a sturdy garden spade first, usually we all have one in garage. Cold chisel and hammer sds drill and chisel if you have (safety glasses, gloves,etc)

    Try and remove high bits of tile adhesive but unlikely you will get it all off

    Sounds like a waterproof membrane as you say, or a bitumen liquid painted on

    Once uv removed as much tile ady as you can (particularly high blobs) then sweep and hoover

    If the concrete is very dusty at this stage, give it a coat of SBR Primer diluted

    Yes I would float over with self levelling compound - 1 sack will do you, Mapei is very nice, around £20

    Once set and dried, 2 coats of Everbuild Blackjack, follow manufacturers instructions, this will sort out any slight damp issues that may be present

    Once B J dried, 1 coat of SBR Primer, diluted as per MI

    Then finally ur ready to tile !

    So several stages of prep, none that difficult or expensive, just some patience and time

    The flatter your surface prior to tiling will make the job better, quicker and more of a pleasure

    Use bagged (powdered) tile adhesive and grout (2 seperate products not combined) as better quality than ready mixed tub stuff

    Check adhesive is suitable for porcelain as many aren’t - and stay away from rapid set as new to tiling :eek:

    Buttering tiles - no not bothered myself, just give each one a wipe over underneath with damp cloth before laying - removes dust and makes em stick

    Then you need tile spacers and a decent tile cutter - porcelain floor tiles can be rather hard to cut

    Sounds like a great project, keep the forum updated :)
     
  3. Dmck

    Dmck New Member

    Amazing - thanks DIYDave , really appreciate it.

    Is there an alternative to the blackjack - a mat type arrangement, like what I think is already in place. It's my front door so there will be foot traffic.... I'd like to try to minimise any drying times if possible.
     
  4. DIYDave.

    DIYDave. Well-Known Member

    Once you lift the old tiles, if no sign of damp and you haven’t been aware of any damp issues over the years, may not even need to add another damp membrane

    The porch floor i recently tiled appeared free from any damp issues and all tiles were firmly stuck down

    Only when I lifted tiles from one corner did I get a whiff of damp so though ‘belt and braces’ approach

    5 lt of Black Jack was around £12 from TS so went with it

    You could lay a polythene membrane which is quick and easy to do

    You will have to sort out access regardless as with all prep stages, there’s drying time to consider - self levelling / SBR / tiles

    You could use a rapid set tile adhesive to speed things up but as it says - it is rapid set / less working time so need to be swift with your tiles

    A sturdy plank of wood to bridge porch floor usually works whilst materials are drying
     

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