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Adding 22mm pipe through joists

Discussion in 'Plumbing and Central Heating' started by sotal, 29 Dec 2020.

  1. sotal

    sotal

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    I need to extend my radiator circuit to add a new radiator and to modify an existing radiator to be fed off that as it is currently tee'd off a rad that is tee'd off another one.

    Anyway it has proved to be more challenging than I first thought! The room next to the room I want to get to didn't have any flow pipes under it and the return pipes was the last part which as far as I'm aware I'm not supposed to tee off after the cylinder return. So I've now pulled the floor up in the next room and found the end of the flow.

    There is also the return pipes at this point. So I want to run 2 22mm pipes from this point approx 3m. To get through the bedroom in between I need to go through every joist. However there are already loads of pipes in that room!

    The existing pipes are all notched into the top of the joists not leaving any room for the new pipes.

    I could go lower and go through the centre of the joists.

    How far away from the notches do these holes need to be?

    There are also a few wires running through holes. How far away do these holes need to be?

    I'm going to be using copper and solder, luckily the room in going into has the joists running at 90 degrees to the rest of the house, so I can lay the pipes down horizontal and slide them into position.

    Any other thoughts would be appreciated!

    Thanks
     
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  3. Elkato531

    Elkato531

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    Building Control Guidance Note 07 (tameside.gov.uk)

    This is the guidance to comply with building regs. There is a good chance, however, that the existing notches and holes may not be properly located and/or sized.

    Last part of the document is what you need.
     
  4. sotal

    sotal

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    Thanks for that, if I'm understanding it correctly then yes you are right that the existing ones don't follow that.

    Is the span the complete length of the wood or the distance between supports?

    Without pulling everything up the first few are about 3.4m long to where the stairs start. The others I presume will go the full length past the stairs so they are around 6m. However they sit on a brick wall at about 3.4m.

    The joists are approx 20cm x 4cm

    So if I took 3.4m as the span.

    Then am I right with the following?...

    Maximum Diameter of drilled hole: 50mm (which will be fine as I was planning on 25mm)
    Distance between holes: 75mm
    Holes to be drilled within the centre 50mm of the wood so at least 75mm from top or bottom.
    Holes should be 100mm horizontally from any notches above
    I can't drill through the first 850mm from the wall (0.25 x 3.4)

    I've checked and the drill and wood cutting bit will fit between the joists.

    Does the above sound correct?
     
  5. Mottie

    Mottie

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    Why don’t you use plastic for the main run, that will be a lot easier to poke through holes.
     
  6. sotal

    sotal

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    The main reason being that I have 3 lengths of 22m copper :)
     
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  8. Mottie

    Mottie

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    Scrap it and buy plastic. :)
     
  9. sotal

    sotal

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    I think I can just about get 2 notched in at about 85cm from the wall which is right on the limit for notching distance. 25mm depth allowed for the notch. The only issue I'll have is that between one pair of joists, there is a pair of 22mm pipes that run perpendicular to these and will be right in the way, so at that point I'll have to use a bunch of right angles to drop the pipes lower and then back up again. Is that acceptable? My other option would be to drop them lower and then keep them low and go through the centre of the last two joists to then connect to the T pieces on the original pipework which will have to be angled down anyway.
     
  10. ianmcd

    ianmcd

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    be very very carefull notching and drilling joists, it can be very costly and your house insurance will not cover any damage you cause, I am talking tens of thousands of pounds if you get it wrong
     
  11. lostinthelight

    lostinthelight

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    If you have OV system its more likely to cause air locks!
     
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