Flooring problem in renovation

Discussion in 'General Chat' started by Pisto_Grih, May 12, 2016.

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  1. Pisto_Grih

    Pisto_Grih
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    Hi All, bear with me as theres a bit to read:

    We are having almost our entire house renovated and remodelled, and we are 85% there, however we have run into an issue that 1) I'm not sure how to approach the builder about and 2) not sure how to solve.

    Basically, we have an old extension on the back that was knocked through to make a large kitchen/diner. This was always planned to have underfloor heating, however, because we didn't want to disturb the existing concrete slab underneath, our builder said he would lay a low profile underfloor system on top of the existing slab after some levelling between extension and old house, and we could floor on top. We also had large bi-fold doors fitted at the end of this space intending for the floor to be flush with the door threshold and a new patio at a later stage.

    The doors went in long before the floor was finished, and I double checked with the builder that we would have space for him to lay the underfloor heating and our finished floor on top (this was planned to be vinyl, similar to amtico or karndean. Usually vinyl tiles are 5-6mm thick. The vinyl tile is about 3mm thick)

    The underfloor heating is now in, a wet system thats run in 18mm foil faced polystyrene boards, and we are left with approx 15-18mm of space between the top of this and the door threshold. The builder is not fitting the floor for us, we are using a separate installer, so he has left the underfloor system bare, ready for whatever goes on top. EDIT: The amount of space between the top of the boards and the line on the door frame where floor should finish is 10mm.

    However, our vinyl installer says he won't fit vinyl or guarantee an installation unless he can lay the vinyl on top of 18mm of ply - this is for structural reasons, so that the floor feels solid underfoot, as well as to glue the vinyl to. The plumber says the insulation boards are fine, just put 12mm OSB boards on top, but installer says no. So the installer needs 24-25mm minimum, and we only have 18mm.

    Alternatively, these foil faced boards are suitable for laying engineered wood flooring directly on to them, however we are now stuck with choosing engineered wood but only wood that is 18mm thick, not the thicker standard 21mm, narrowing our choices quite a bit. The installer isn't keen on that either, although this might be for guarantee reasons, not installation guidelines.

    So our options are either, go with an 18mm engineered wood floor which potentially might be a little bouncy over the underfloor, or the two big ones which I would prefer to avoid: remove the brand new bifolds and refit about 15mm higher - which would mean re-plastering inside and re-rendering outside, OR lifting all the underfloor heating and digging down into the subfloor by 15mm, which I can't quite see happening.

    EDIT: The amount of space between the top of the boards and the line on the door frame is 10mm, ruling out pretty much every floor covering. There is no space to allow for standard sub floor preparation in the form of 18mm ply or screed, and then a finished floor on top. We need an additional 20mm of space to allow for most floor coverings.

    The builder had a planned 5 week trip which we knew about and he has now gone away, leaving the house just after 2nd fix stage had started, his electrician and plumber have been back and forth but we can't do much until the floor is down in the back room.

    Strictly speaking, he has left us enough space for flooring, but not really. He knew from beginning that we were planning vinyl floors, so speccing polystyrene insulation is his mistake surely?

    Any thoughts? I don't want to get into an argument with the builder just need a solution.

    New Question: Has anyone successfully removed and refitted aluminium bi-fold doors without affect the integrity of the frames and/or voiding the guarantee? Of course I will get the bi-fold installer to come back and fit them.
     
    Last edited: May 14, 2016
  2. Wahreo

    Wahreo
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    15mm tongue and groove WBP ply and LVT on top of that?

    The Karndean/Antico is usually 2/3mm thick.


    Essentially it's a floating floor right?

    Im assuming there's a tad more than 18mm clearance from the UFH to the door threshold? ......as you suggested 18mm engineered flooring.
     
  3. Pisto_Grih

    Pisto_Grih
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    No, maximum is 18mm, and that's to the very very top of the threshold, above the bevelled edge.
     
  4. Steve N

    Steve N
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    I suspect that 12mm OSB "could" be fine. It might be worth getting a second opinion on this.

    Alternatively.
    If you went for the 18mm engineered wood floor, which I think could look really good.
    Would it be possible/practical to place some wooden noggins or something in between some of the polystyrene boards beneath. This would provide the stability you need for the engineered wood floor laid on top and remove any bounce effect.
     
  5. Pisto_Grih

    Pisto_Grih
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    Here is a picture to better illustrate the problem:
    [​IMG]

    You can see the line where the floor should come up to (the first horizontal line above the foil) - this is about 10mm. Right to the very top of the door frame is 17-18mm but this is a bodge and really shouldn't get up this high.

    So really we have 10mm of space to fit a finished floor surface. And the only thing that can go directly on top of these foil faced expanded polystyrene boards is engineered wood.

    The polystyrene is much too soft for tile, and even if it was rock solid, a decent floor tile is minimum 9mm thick, so no space for adhesive and ditra mat etc.

    Our vinyl supplier can only guarantee if stuck on 18mm ply, but even 9 or 12mm is too thick.

    Engineered wood is too thick, even at the thinner end of the market.

    The last thing we've looked at is poured resin floors, as they are only around 3-4mm thick, however they require a solid sub floor to pour onto.

    So now i'm trying to find a self levelling compound that can be poured over this tiles, to around 2-3mm thick, that sets hard enough to take a resin floor, but flexible enough not to crack because of the softness of the polystyrene!
     
  6. MrSossidge

    MrSossidge
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    Not ideal but could you not taper down to the door from the required height that is recommended.
     
  7. teljess

    teljess
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    i dont think that you will get any latex/compound that you could use that would be strong enough to take a resin floor it would just keep cracking.another idea would be to remove the underfloor heating and use the electric version which be alot thinner giving you the height on the door cill for the floor that you want.
    i dont think that any of the options that you have are going to be cheap,the bi folds cill should have been higher
     
  8. swiftpete

    swiftpete
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    18mm floor directly on top of the rigid insulation will be fine, totally solid and it won't be bouncy. I fit insulation and timber over the top of it all the time at work. There isn't any give in the insulation when the the timber spreads the weight. If the current floor installer won't install a floating floor over the insulation, find someone who will.
     
  9. Pisto_Grih

    Pisto_Grih
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    I've edited the first post to reflect the updated information. To be clear, this is the builders mistake so he will definitely be contributing, if not paying, for the cost to remove and re-fit bifolds if necessary. I even spoke to the plumber yesterday who looked at his install and the door frame and he agreed there is not enough space for a floor to be laid.

    Electric underfloor system is not an option, as this will be the main living space and too expensive to run. We've thought about ripping out the underfloor heating and resorting to radiators, however that would ruin the whole design of the room and it would be more disruptive to run new pipes than it would removing the doors.

    Removing the underfloor and digging down is a) too costly because the pipe runs are in plastic coated metal, and can only be run once before pipe integrity is compromised, so new pipes would need to be laid, and b) we don't know how deep the concrete slab is underneath so we would potentially have to remove it entirely and lay a new slab (digging down 150-200mm, new insulation, new DPM, concrete slab, curing time etc) Massive disruption and adding months onto the build.

    The only thing I can think of is a compound that can be poured over the tile around 2-3mm deep that is flexible enough to cope with minor compression, then a poured resin or poured floor system over the top of that. But all the installation specs I've seen for resin floors also require a suitably hard screed or 18mm ply board!
     
  10. swiftpete

    swiftpete
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    6mm osb and 3mm flooring then.
     
  11. Pisto_Grih

    Pisto_Grih
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    We had a chat with a local independent on Saturday who is willing to install vinyl over 10mm of compound, feathering out the compound a few mm towards the door so it will fit. A barely perceptible decline, 3 or 4mm over a couple of feet. Had not thought of this but he said it wouldn't be a problem.

    He also said we could have wood, as he could fit a bit of trim that hides the height discrepancy, it would need a gap before the door anyway for expansion.

    So, panic over, for now!
     
  12. Rorifett

    Rorifett
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    can we get before and after pictures?

    Or just after pictures as I can now finally see the before one :D
     
  13. jaipal2004

    jaipal2004
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    I had a similar issue with a retrofit wet underfloor system using dry screed boards. We were told we can tile on top directly but if we want carpet or cheap laminate (7/8mm) then a 6mm ply would need to be used.

    Checked with manufacturer and they said we can lay a 12mm laminate directly on top.

    You should be able to get away with 6mm ply if your boards are rigid?

    Ta
     
  14. Pisto_Grih

    Pisto_Grih
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    The independent came round to inspect, and has spoken to the panel manufacturers too who have confirmed it will be fine with 6mm plywood screwed down, then a flexible screed on top. Going to book him in today.

    I need to do a bit of prep work first, glueing some of the panel edges down, and many many more screws, so looks like a weekend spent on my knees with my tool in my hand, again.
     
  15. Wahreo

    Wahreo
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    6mm ply screwed to what?

    Does the 6mm ply need some kind of alkali resistant scrim on there I wonder?
     
  16. Pisto_Grih

    Pisto_Grih
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    Screwed through to the concrete underneath. The ply will be marine ply apparently.
     
  17. Wahreo

    Wahreo
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    Oh gotcha.

    Christ, that seems thin, especially screwing it down.

    I would've thought 9mm would be more sensible
     
  18. Pisto_Grih

    Pisto_Grih
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    don't tell me that! the expanded polystyrene is only soft when you apply point pressure, it feels stable when walking over it.

    It will all be fine in the end, it will all be fine in the end...
     
  19. Wahreo

    Wahreo
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    I often use 6mm ply for vinyl flooring. Screwed directly onto existing tongue and groove or chipboard.

    I screw ever 6". Having to screw using long screws and plugs etc might be a challenge for the 6mm ply. Especially if you have to countersink the heads of the screws which I always do
     
  20. Pisto_Grih

    Pisto_Grih
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    well half of the floor was raised with 18mm chipboard, then the underfloor panels, the other half was levelled with compound then underfloor panels.

    So for half the room, the ply can be screwed through the panels to the chipboard, the other half I assume will be concrete self tapping screws straight through the panels into concrete.

    Then 2-3mm of compound over the whole lot.

    My next panic is that they hit one of the pipes when screwing through although i'm assured they'll mark it out very carefully.
     
  21. Too late

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    I doubt anyone would want to risk screwing through . With a wet system underneath . And what exactly are they screwing into ?

    I would relax a bit and not do anything yet until you are more than 109% positive what ever work can be achieved . With the best will in the world . It would be easy to put a screw through a pipe .
     
    Last edited: May 19, 2016
  22. Wahreo

    Wahreo
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    6mm ply with poor screw spacing might be a little iffy.

    I'm not really convinced.

    I've walked away from a few floating floor tiling jobs myself despite Adhesive manufacturers ensuring me it'll be fine.

    I'm wondering if your 6mm ply could be glued and screwed?
     
  23. Too late

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    As above . I cannot think where the screws are going to attach .
    Sometimes we upset Clients as we refuse to do work. Anyone can "have a go" but a sensible person will back off if they can see a issue . Also 6mm is too thin I think .

    It's gone wrong.But it can get a lot worse very quickly if you rush .
     
  24. Pisto_Grih

    Pisto_Grih
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    OK, half the room will have the following levels (from the top level down)

    Vinyl (2.5mm) > Adhesive > Levelling Compound (2mm) > 6mm marine Plywood > 18mm EPS foam > 18mm Chipboard > Concrete screed. The screws will attach the plywood to the chipboard, sandwiching the foam.

    The other half of the room will have the following:

    Vinyl (2.5mm) > Adhesive > Levelling Compound (2mm) > 6mm marine plywood > 18mm EPS foam > levelling compound > Concrete screed. The screws will go through the plywood all the way through to the concrete screed, sandwiching the foam.

    My prep at the weekend is glueing down the loose edges of foam and adding a few more screws per sheet to ensure no movement at all.

    With some pan head screws, the levelling compound will cover any screwheads proud of the ply?
     
  25. IronGiant

    IronGiant
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    You want countersunk surely?
     
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  26. Pisto_Grih

    Pisto_Grih
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    Or those - it wont be me doing the ply part, thats for the installers.
     
  27. Too late

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    What fixing method do you plan to use in the screed ?
     
  28. Wahreo

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    Whatever is used, I'd want it glued down too.

    I still would prefer to see 9mm used. 3mm makes a huge difference
     
  29. IronGiant

    IronGiant
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    As I say to...

    maybe not :laugh::devil:
     
  30. Too late

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    And tape the joints with fibre
    .
    Thank god it's not a wet room . Just
    Cannot see it staying still
     

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