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Underfloor heating

Discussion in 'Plumbing and Central Heating' started by deuce22, 28 Aug 2010.

  1. deuce22

    deuce22

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    Hi.

    I have just finished some remodelling on my house and I have changed the front part to an open plan Kitchen/Living/Dining room.

    The floor area is roughly 50m2 and I need to have 32000 BTUs throughout.

    I can fit it out with a number of radiators, but I would prefer to have underfloor heating instead.

    The budget I have for the heating of this area is not massive, so I cannot choose U/F heating if it costs to much.

    I have calculated that the radiators will cost around £500 and I am trying to work out what the U/F heating would cost.

    A friend told me that he had put U/F heating in a living/dining room, but did it himself and it didn't cost that much.

    Although I would be happy to do it in a similar way if it didn't cost a ridiculous amount, I don't want to be doing it if it's not that safe.

    What is the cheapest way of installing U/F heating, I have a 32KW boiler that I would like to connect it to.

    Thanks.
     
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  3. crockett

    crockett

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  4. deuce22

    deuce22

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    Thanks crockett.

    I have had a quick look through that site, but cannot find all the info I need.

    Do you know if you can put U/F heating under bevellloc laminate flooring and can it be laid straight on top.

    Thanks.
     
  5. simond

    simond

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    Here you have the dilemma.

    The UFH manufacturer won't warrant the wood floor surface (and why should they), and the manufacturers of the wood floor will not give you any assurances either.

    Generally speaking, an 'engineered wood' floor will tolerate UFH better and be less inclined to warp and shrink than natural wood. But I'm not giving any guarantees either. :LOL:
     
  6. deuce22

    deuce22

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    Thanks simond.

    I'll have to look into this a bit more.

    I don't want to be spending all the effort and money on the flooring, to have to change it in a few years.

    Do you know if the flooring can drop straight onto the U/F heating (obviously on some form of matting) or does it have to be screeded first.

    Thanks.
     
  7. DeltaT

    DeltaT

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    You need to give us more details Taffy, I'd love to advice you but you need to confirm the following:

    What is the whole floor construction?
    Is that a net area, with kitchen units etc excluded?
    32K BTU is a hell of a lot of heat, are you sure you've done your heat-loss calc correctly??
     
  8. deuce22

    deuce22

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    Hi DeltaT

    I'll try and give you as much info as I can.

    The property is a Bungalow,

    2 En-suites
    4 Bedrooms
    1 Bathroom
    An open plan Living, Dining, Kitchen.

    The whole property has vaulted Ceilings with Velux windows in certain rooms.

    I have 100mm insulation in between rafters and 40mm on the face.

    I'm sure that the whole property needs around 60/70,000 BTU's and I've had a reading back of 32,000 BTU's for the open plan area.

    It has a floor area of 50 m2 excluding units and the floor material is concrete.

    The boiler I have is a 32 KW, so I'm sure that it will cope with this.

    I don't understand 100% how the figures all work, but am I right in saying that if the boiler is 115,00 BTu's it can give off that amount of heat through either U/F heating /radiators.

    So in my case it will be fine.

    The Plumber I've been using is an older person, who still reverts back to ways that he used to do things years ago and so to be sure I would just like to clarify everything myself.

    Thanks.
     
  9. DeltaT

    DeltaT

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    So the existing floor is concrete?? So do you need an overlay system on existing concrete? Then you want to put laminate down?
     
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  11. deuce22

    deuce22

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    Yes, it is an existing concrete floor, but I don't know what I need to do, so I can lay laminate on top.

    I would prefer to have U/F heating, but there is a budget that I need to stick to.

    I need to achieve around 32,000 BTU's and have looked at water VS electric.

    The electric doesn't seem to give off as much heat compared to water, but I think I can get enough heat off it to be able to use it.

    I can lay the floor straight on top of the electric, but I'm unsure if I can do that with water.

    I need to compare all the variables and then calculate costs.

    Thanks.
     
  12. picasso

    picasso

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  13. deuce22

    deuce22

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    That looks like exactly what I need, but I need to find out the costs of it.

    The only problem I think that I can see is that it doesn't give off enough heat.

    It say's 100Wm2 and that will give me only 4000 Watts, but I think I need roughly 9500 (32000 BTU's).

    Thanks.
     
  14. deuce22

    deuce22

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    Hi.

    I have just spoken to a friend who knows of someone that has had is wet underfloor heating down for around 5 years with no problems.

    However it seems really strange to me how he has done it.

    In theory it seems to work, but I don't know if it is possible and the person is either telling porky's or leaving something out.

    He has connected plastic speedfit to a valve that is connected to the rest of the central heating plumbing.

    He has laid insulated matting to the floor area that is going to be heated and clipped 15mm pipe directly to the floor using forming bends throughout.

    He has then fixed timber in between each pipe as closely as possible and then fitted his timber floor directly on top.

    I don't know if this is possible.

    Can someone please give me some feedback.
     
  15. mointainwalker

    mointainwalker

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    With wet UFH you will neither be able to meet your heat requirements nor fit it within your budget.

    Your heat requirents seem very high.

    If they are correct, I think you could better invest some of the budget in insulation.

    How many m2 does your mate's UFH described above cover and is there just the one circuit ?
     
  16. looneyfitter

    looneyfitter

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    I agree. That his heat calc does seem high. I would advice you get in touch with speedfit, polyplumb and ask them to survey.

    There are simple ways to over lay that can be very cost effective. One method is to lay foil insulation over the area to be heated(screw fix sell 20m2 at 100notes) then lay 20mm batons at 350-400mm centers and run your 15mm circuits at 150 centers. ( in general i run 2 circuits to feed 20m2) this is overkill but my preference. You then spread kilndried sand within the battons, this then absorbs the heat and acts as a radiant. I then use 12mm ply over the top screwed to the battons. Ultimate underfloor heating provide some very cost effective manifolds

    HTH
     
  17. deuce22

    deuce22

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    Hi.

    The friend i've been talking to is a plumber, although he's only been qualified for a year, so he hasn't had much experience.

    He's done some work in this guy's house and that's when he was told how he'd laid the U/F heating.

    I used an online calculator to work out how much heat I need to achieve.

    The ceilings are vaulted with three Velux windows in the roof. The lowest point is about 2.4m and the highest 3.4.
    There are to big bay windows fitted and a door and window in the kitchen area. The total floor area is about 60m2.

    The way looneyfitter has described is similar to what this guy has done it, so it does sound like this is possible.

    I'm not sure exactly what you mean by circuits, but couldn't the pipe be laid down and be connected to a valve, once the valve is open it heats the whole length of pipe.

    Do you need a manifold. This guy has gone straight into a type of radiator valve.

    Thanks.
     
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