I have been strongly advised by my (trusted, reliable and experienced) plumber against underfloor heating. A number of friends also advise against it and say they have had endless problems with their UFH, requiring floors to be repeatedly taken up.

We are renovating a 1960s bungalow and had hoped to use UFH in what will be the very large kitchen/diner – so many people in the Homebuilding Magazine articles seem to use it with no mention of problems. Any unbiased advice would be appreciated as I love the obvious no-need-for-radiators advantage but dread the thought of endless flooring nightmares!?

Comments
  • Anonymous

    I’m sure there are horror stories but I’m surprised that your plumber has such a negative sentiment about it. We’ve personally had it for 8 years without any form of hassle whatsoever, and UFH is now regarded as a standard choice in most bespoke homes. The only potential weaker areas are around the joints as they meet the manifold – modern PEX piping is so well developed that it usually comes with significant guarantees.

    Ultimately you have to specify what you feel comfortable with, but I can honestly say that concerns over UFH are largely ungrounded. A lot of modern plumbing pipes end up behind walls or under floors anyway, so going for rads wouldn’t necessarily mean you have a trouble-free heating system.

    Next step for you would be to contact one or two of the big suppliers – they will be able to reassure you much more than I over its long term durability.

  • Stan Ratajski

    I am a builder and we have been successfully installing underfloor heating systems for at least 5 years. If you think about UHS – there is not much to go wrong under the floor. There is just a pipe there and, if you use PEX-AL-PEX pipe it’s got 20 years warranty. It is exactly the same risk as to the pipe in the wall. Problems may appear with manifold, pump, etc but this is all accessible without lifting any flooring.
    From my customers feedback I believe it is very comfortable and, in a longer run, economical solution.

    But there are some disadvantages:
    Firstly, if you install wooden engineering floor as a finish, most probably the wood will start shrinking and you will see some gaps between boards here and there. Not massive but 1mm or so. In few projects we used specially prepared engineered flooring with moisture level below 8% during the installation and still in cold months there are minor gaps between some boards.

    Secondly – uneven floor temperature. It depends of the floor structure and the floor finish. Eventually, if you go for engineered flooring (best to be glued to the firm surface) then I believe there is no way to avoid uneven floor temperatures. The concrete or fermcell boards doesn’t spread the heat equally and there is a little hotter area directly above the pipe and colder area in the gap between pipes. This is not a massive problem but it exists.

    Other than that – I believe it’s great heating solution for a big room like yours.

  • Rachel Haynes

    Both answers above are very good and I’ll try not to repeat any of them. From our experience, as long as the under floor heating system is installed correctly the only other problem is linked to the floor construction type and the client’s aspirations of how the UHS will perform. I’ll explain…

    In most new builds we have put UHS in a floor screed above insulation and a slab. In many refurbishments the UHS has been fixed between the existing floor joists on insulation with metal spreader plates fixed around the pipes to transfer the heat upwards. Both methods are fine and will give you the benefit of a warm floor and no walls taken up by radiators.

    But, with a screed masonry floor the heat from the UHS will be retained in the thermal mass and be spread more evenly on the whole. This means that the room will stay warm for longer after the heating is switched off as the absorbed heat is released into the room. A timber and metal spreader plate floor will cool as rapidly as a radiator and so the room will cool quicker. On the flip side a timber/ metal plate system is generally more responsive to heating a room than a screed system as the screed system will only work a full efficiency once the screed has been warmed. This should only be a problem though if heating a room from cold.

    We will always ensure that if we have to go down the timber/metal spreader plate route that the Client is fully aware of the difference between this and a screed system as from the experience of others, they can be disappointed with the comparative more rapid cooling of the system as what they generally will have in mind is the slow and more constant heat release of a screed system. (There are some suppliers who will offer a halfway house of a UHS set between joists but with a 30mm screed covering also between the joists that will give some of the thermal mass benefits).

    Other than that, recognising that carpet and timber are natural insulants and so aren’t as good above a UHS than a tile or stone floor are is the only other "downside" that we have come across. Oh, and make sure you know where to hide your manifold as they are ugly!

    In short, we’d always recommend under floor systems – just understand how the system you are going to use works. And last piece of advice – make sure the fitter draws an accurate plan of the layout of the pipes for future trades and your use – always useful to know where they are!

    All the best

    Thread Architects

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