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Underfloor heating in a first floor bathroom

  • 27-10-2009 04:45PM
    #1
    tails_naf
    Registered Users, Registered Users 2 Posts: 862 ✭✭✭


    Hi All,
    I am in the process of building a new house and have decided to put under-floor heating in the upstairs bathrooms (nice warm tile effect under foot really appeals to me).

    It seems this is not that easy though - I have been looking into a few options:

    1) In-between joists - using either aluminumum heat-spreader plates, or insulation and a thin sand-cement screed is one thing that is done. However, I wonder if the heat will really penetrate througn the 18mm osb above, as well as the 10mm plywood above that, and then the tile?

    (As far as I can see online, you must have at least 18mm osb and then a furhter sheet of plywood to allow the floor to expand in a way that will not cause the tile to lift).

    The problem with this method is: the floor is already nailed down (timber frame, floor was installed before I knew it), so will have to run pipes from the bottom side - not easy!



    2) Batten out 1" battens on top of the existing 18mm osb, 200mm centers top add the 10mm plywood and then tiles. Use sand-cement between battens and run the ufh pipe in this.
    This has advantages in that its easier (work done from the top), cheaper - no need for heat spreaders, and distance between the heat source is smaller as the heat must only travel through the 10mm ply.
    The downsides are: a) is this good enough for tile, 10mm osb on 200mm centers battens, and b) this will create a floor level that is at least 1" above the other floors - causing a step up into each room.

    So, can the wise people of boards direct me to the best solution. The 1" step into the bathroom sounds like something that would always bother me - but also the heat penetration through 18mm osb and then 10mm ply is also a concern. It feels like a real rock and hard place type decision!


Comments

  • #2
    sinnerboy
    Closed Accounts Posts: 5,433 ✭✭✭sinnerboy


    You are probably best to run with electrical UFH , assuming the rest of the floor is heated with rads . All the diy stores have it .


  • #3
    tails_naf
    Registered Users, Registered Users 2 Posts: 862 ✭✭✭tails_naf


    Thanks for this - I had actually looked into this, but it's fairly expensive. I'm talking about 20m2 total bathroom area (1 main bath and 2 en-suites), and quick costings seem to suggest I'd be shelling out 2 grand for this.

    I already have the materials (inclduing manifold, pump control, stats, etc) for the wet-underfloor heating, which is why I'm really trying to avoid the mats if at all possible!


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