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ARE MY drilled and notched floor JOISTS RUINED?? (moved)

Discussion in 'Floors, Stairs and Lofts' started by wekkah, 15 Sep 2016.

  1. wekkah

    wekkah

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    So we had central heating installed and were later told that the plumbers had cut through the joists when they shouldn't have- the floorboards were essentially resting on the pipes etc.... So then somebody came along and drilled holes through the joists under the cuts to feed the pipes through instead... see photos...
    I can't help but feel like they have weakened an already weakened joist... Is this correct??? What shall I do?

    (The cuts/holes are in the middle of the joist - the centre of the house)
     

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  2. motorbiking

    motorbiking

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    I'd plate them as best as possible or better still run some additional "sister" joists at least 18" each side of the damage, spacing screws/bolts evenly and off-set if you can. They don't look good, but they may have been over specified to start - its not easy to know. You can also plate them with ply if that is easier.
     
  3. chappers

    chappers

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    depends where they have notched and drilled and the sizes of the notches and holes.
    The reality is it will almost certainly be OK. When I ripped out my bathroom years ago the 75mm floor joists had been notched by about half of their depth along every joist, the bath had sat on there fine since what looked like the 70s and hadn't ended up in the kitchen.
    Do a search on notching and drilling floor joists if you want the definitive answer
     
  4. John D v2.0

    John D v2.0

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    If the damage is near the middle you'll probably find the floor is more bouncy than it should be, if it's closer to the supports then it might not be strong enough, but probably is.
    Like chappers above I found our bathroom joists of 175mm have all been notched too close to the centre and in some cases more than half the depth. The floor is generally like a drum now but it's held for 30+ years. When I get the chance I'm going to reroute the pipes and repair, and I'd recommend that to you too.
    Officially you should either replace or sister using bolts and long bits of ply after having it calculated, but I'll probably just screw and glue plywood and see how it goes.
     
  5. John D v2.0

    John D v2.0

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    PS just to put your mind at rest, wood is designed to flex lots without breaking. Just look at any tree in the wind.
    In construction, we use relatively huge sections of wood to minimise this natural flexibility.
    So you're mostly getting deflection but in the absence of huge knots or other defects your floor won't fall.
     
  6. 80sman

    80sman

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    I found some of my joists like this, I filled the cutouts with Epoxy and plated the damaged areas. Technically I suppose I should have had it all recalculated.......

    Bought supplies from this place.

    http://www.joist-repair.co.uk/notches.htm I'm not affiliated with them in any way, so apologies if the link is wrong.
     
  7. PrenticeBoyofDerry

    PrenticeBoyofDerry

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    A bit of butchers job and unsure how they intend to run copper pipe through holed joists.
    I have seen much worse and those buildings as far as I am aware are still standing.
    By the book, they look like they would fail building regulations part A. Here is a guide.
    http://www.diynot.com/wiki/Electrics:route
     
  8. Having looked at the website, I suspect it's the heavy duty steel strapping that's providing the real support, and bonding the straps would seriously increase the strength. The epoxy would be good for filling complete holes, but won't do much for wrapping round existing pipes.

    If there's no real deflection along the joists, then they're very likely okay, but the metal straps (definitely not ply) should set your mind at rest,
     
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