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UFH + floor insulation

  • 25-03-2008 11:04am
    #1
    termon8r
    Registered Users, Registered Users 2 Posts: 47 ✭


    I need some advice about UFH and floor insulation.

    I am building a 2-storey house with a basement with concrete slabs on ground floor (over basement) and first floor.

    The slabbing will be finished next week and then I need to have the UFH installed and the sand and cement screed poured.

    On the ground floor I have allowed for 60mm floor insulation which should be sufficient but on the first floor I did not allow for any floor insulation as I was advised at the time that I didn't need any.

    However it has been brought to me attention since that it is important to put insulation on the first floor also with UFH.

    At a squeeze I could lay 25mm of floor insulation. I have allowed 100mm therefore 25mm insulation + 75mm for UFH and screed. Do I really need to?

    Does anyone have any comments on this?


Comments

  • #2
    sydthebeat
    Subscribers Posts: 42,170 ✭✭✭✭sydthebeat


    firstly, its not exactly necessary.
    If you think about it, the first floor concrete slab is going to be heated by the ground floor heating system anyway, so not allowing heat into it from the first floor UFH isnt going to make much of a difference.

    Personally i would insulate it just to increase the responsiveness that extra bit in the first floor. You have a few options.
    As you say you have allowed 100 mm so you could install 35mm insulation and 65mm concrete screed (with reinforced mesh), or you increase the insulation and pour a thin screed such as easi-screed etc. I would go for the first option myself.


  • #3
    yop
    Moderators, Home & Garden Moderators, Regional Midwest Moderators, Regional West Moderators Posts: 16,724 Mod ✭✭✭✭yop


    We put UFH upstairs on ceiling joists covered with OSB.
    I put down 50mm battens, 25mm insulation between and the UFH and a light screed. Never an issue with it.


  • #4
    ircoha
    Closed Accounts Posts: 2,290 ✭✭✭ircoha


    termon8r wrote: »
    I need some advice about UFH and floor insulation.

    I am building a 2-storey house with a basement with concrete slabs on ground floor (over basement) and first floor.

    The slabbing will be finished next week and then I need to have the UFH installed and the sand and cement screed poured.

    On the ground floor I have allowed for 60mm floor insulation which should be sufficient but on the first floor I did not allow for any floor insulation as I was advised at the time that I didn't need any.

    However it has been brought to me attention since that it is important to put insulation on the first floor also with UFH.

    At a squeeze I could lay 25mm of floor insulation. I have allowed 100mm therefore 25mm insulation + 75mm for UFH and screed. Do I really need to?

    Does anyone have any comments on this?

    OP the post gives the impression that the UFH etc is going in before any of the interior walls on ground or first floor , or am I mistaken?.
    yop:We put UFH upstairs on ceiling joists covered with OSB.
    I put down 50mm battens, 25mm insulation between and the UFH and a light screed. Never an issue with it.
    Could you plait explain the overall sandwich here, starting from the top

    Floorcovering
    xx
    xx
    Ceiling joists

    Thanks
    Ceiling slab


  • #5
    yop
    Moderators, Home & Garden Moderators, Regional Midwest Moderators, Regional West Moderators Posts: 16,724 Mod ✭✭✭✭yop


    No prob,

    covering is semi solid, then underlay which lies on the batten/screed.

    Battens are 25*50mm, which are screwed to the OSB which is on top of the ceiling joists.
    In between the batten I cut 25mm thick insulation and then clippled my UFH pipes to this.
    Then I filled screed in between the battens.


  • #6
    sinnerboy
    Closed Accounts Posts: 5,433 ✭✭✭sinnerboy


    termon8r wrote: »
    I need some advice about UFH and floor insulation.

    I am building a 2-storey house with a basement with concrete slabs on ground floor (over basement) and first floor.

    The slabbing will be finished next week and then I need to have the UFH installed and the sand and cement screed poured.

    On the ground floor I have allowed for 60mm floor insulation which should be sufficient but on the first floor I did not allow for any floor insulation as I was advised at the time that I didn't need any.

    However it has been brought to me attention since that it is important to put insulation on the first floor also with UFH.

    At a squeeze I could lay 25mm of floor insulation. I have allowed 100mm therefore 25mm insulation + 75mm for UFH and screed. Do I really need to?

    Does anyone have any comments on this?

    current regs require u value of 0.15 for UFH on ground floor - you will most likely need 120mm PU for this

    better to insulate upper floor to increase responsiveness 25 PU + 75 screed is what I would do .

    make sure to place min 25 PU around the edge of your screed in all cases


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