Decking outside

Discussion in 'Tilers' Talk' started by Steve10123, Jul 6, 2021.

  1. Steve10123

    Steve10123 Member

    Hi all. So I've had a nightmare. I currently have decking outside. I planned to take the boards up and leave the frame, then clad it with No More Ply (I was told that it would be strong enough) and then put 40-50mm of concrete on top to lay my 20mm porcelain tiles.

    I have just laid the NMP and snapped two already as its no way strong enough.

    I am trying to figure out what to do now and wondering what you think is viable.I don't really want to rip all of the decking frame up if I can help it.

    Fill the voids of the decking frame with MOT or similar to bring it all up to the level of the frames and then fit the cement and tiles on top of that.

    Lay sheet wood on the decking frame and then NMP over the top and then tile (however I worry this is now making it even higher for my air bricks etc. (I have ready access to lots of chipboard but not sure if I can weather proof this and use it, even thought it will be under NMP and cement and then the tiles, in theory the only moisture will be coming from underneath and won't be direct. Will this work?

    Sack the whole thing off. lol. Actually this isn't an option but anything else anyone can advise?
  2. DIYDave.

    DIYDave. Screwfix Select

    What thickness NMP have you used ?

    In the above application, over a decking frame, should be the 18-22mm T&G stuff that basically replaces floorboards and fixes direct to floor joists

    Wether it will then withstand the weight of 50mm concrete and porcelain tiles on top …… no ideas (but can’t imagine that’s a good combination) :eek:

    Call NMP in the morning - guess they have a technical department for advice

    But ‘if’ you’ve used the thin stuff, 6/12mm (?), then that’s for walls or over-boarding floorboards

    I recon a re-think is needed
  3. AnotherTopJob

    AnotherTopJob Screwfix Select

    I wouldn't personally lay tiles over a wooden frame/sheet of any kind outside. It will bounce and move slightly resulting in cracks, and eventually the wood underneath will rot.

    Option 1 sounds OK but really best to remove as much wood as possible as it will eventually rot and leave weak areas.
    Truckcab79 likes this.
  4. Truckcab79

    Truckcab79 Active Member

    As above but that’s only the best of the two options you suggest. Really you should remove the frame and use the space left to build a proper base. Wood has no place in your build other than perhaps if the size suits your needs and you use the perimeter frame as a former for your concrete.
  5. Steve10123

    Steve10123 Member

    Thank you all. NMP is going back to the shop where it blows. Basically they showed me a mock up and said stand on it and see how strong it is compared to the 22mm ply alternative they had. So I bought it. Then when I called and said they're snapping they said "oh yea, well it was on TOP of a piece of 22mm ply too". How am I supposed to know that, i thought it was just the concrete board.

    Anyway, the frame is coming out, MOT will go in and tile it properly. Will probably work out cheaper too!

    Thanks again all.
    Truckcab79 likes this.

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