Having begun to install underfloor heating upstairs while renovating and extending our property, the Building Inspector has informed us that we need to install spreader plates. This does not seem to be common practice and is not specified in the manufacturers instructions. Our plumber is following common practice of clipping the heating pipes to the interfloor PIR foil faced boards.
Is this part of the Building Regulations and if not can he enforce this stipulation?
Alternatively can we use unformed aluminium plates cut to fit the joists and if so what thickness should be used?

  • Rachel Haynes

    Hello. On all the systems we have installed the UFH pipework has either been clipped to the insulation and then embedded in a screed or sat within a metal spreader plate above insulation when a screed has not been viable. The screed and the spreader plates act the same way to disperse the heat from the pipes evenly across the floor area. Without the screed or plates the pipework will only heat the floor finish directly above them so there would be potentially some temperature differences across the floor.

    I’m not sure whether it is a building control issue in itself, it may be the Officer is just giving advice. However, I would advise checking with the UFH manufacturer directly first (their technical department is always a good starting point) and confirm their design with the Building Control Officer to ensure it is installed correctly and will be passed.

    If you are renovating a property then a common problem with older houses is that the joist spacing isn’t constant or a standard size and therefore a standard spreader plate is not suitable. In these cases we have often suspended a 50mm piece of rigid insulation between the joists on noggins with the top face of the insulation held 25mm from the top of the joist. The 25mm gap allows the UFH pipework to be laid out and then covered with a 25mm layer of dry mix screed. The screed helps spread the heat. This is only suitable for timber floors and the timber used should be rigid enough to span between the joists as the insulation/screed is not load bearing. When using this method the joists should also be checked to ensure they can take the load of the insulation/ screed and floor prior to carrying out the work. However many UFH suppliers use this method now.

    Hope this is of use.

    Hope this is of help.

    I’m not sure that this would be a building control issue

  • Post a comment
    You must be logged in to comment. Log in