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UK diy (uk.d-i-y) For the discussion of all topics related to diy (do-it-yourself) in the UK. All levels of experience and proficency are welcome to join in to ask questions or offer solutions. |
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#1
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Hole in Joist
I need to bore a hole in a joist to take a shower waste. Reading the regs
tells me that in a 20cm Joist the max hole can be 32mm I need to pass a pipe of 42mm diameter! The joist is right next to a wall at the outer edge of the house - load on it will never be high. Pragmatically - would you go ahead and bore the hole? |
#2
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Hole in Joist
DerbyBorn wrote: the regs tells me that in a 20cm Joist the max hole can be 32mm I need to pass a pipe of 42mm diameter! Reinforce the joist by bolting metal plates to both sides? |
#3
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Hole in Joist
On 26/06/2019 18:23, Andy Burns wrote:
DerbyBorn wrote: the regs tells me that in a 20cm Joist the max hole can be 32mm I need to pass a pipe of 42mm diameter! Reinforce the joist by bolting metal plates to both sides? Or bolt it to the wall. -- Adam |
#4
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Hole in Joist
the regs tells me that in a 20cm Joist the max hole can be 32mm I need to pass a pipe of 42mm diameter! Reinforce the joist by bolting metal plates to both sides? Or bolt it to the wall. Access would be very destructive. |
#5
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Hole in Joist
On 26/06/2019 18:33, DerbyBorn wrote:
the regs tells me that in a 20cm Joist the max hole can be 32mm I need to pass a pipe of 42mm diameter! Reinforce the joist by bolting metal plates to both sides? Or bolt it to the wall. Access would be very destructive. So not as simple as just lifting the boards either side of the hole then:-( -- Adam |
#6
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Hole in Joist
On 26/06/2019 18:17, DerbyBorn wrote:
I need to bore a hole in a joist to take a shower waste. Reading the regs tells me that in a 20cm Joist the max hole can be 32mm I need to pass a pipe of 42mm diameter! The joist is right next to a wall at the outer edge of the house - load on it will never be high. Pragmatically - would you go ahead and bore the hole? Yes. (noting a hole in the centre is better mid span, and a notch better near the ends) -- Cheers, John. /================================================== ===============\ | Internode Ltd - http://www.internode.co.uk | |-----------------------------------------------------------------| | John Rumm - john(at)internode(dot)co(dot)uk | \================================================= ================/ |
#7
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Hole in Joist
John Rumm wrote in
o.uk: On 26/06/2019 18:17, DerbyBorn wrote: I need to bore a hole in a joist to take a shower waste. Reading the regs tells me that in a 20cm Joist the max hole can be 32mm I need to pass a pipe of 42mm diameter! The joist is right next to a wall at the outer edge of the house - load on it will never be high. Pragmatically - would you go ahead and bore the hole? Yes. (noting a hole in the centre is better mid span, and a notch better near the ends) I now reckon I am okay up to 50mm on a 200mm deep joist: https://www.labc.co.uk/news/how-get-...-solid-timber- joists |
#8
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Hole in Joist
"DerbyBorn" wrote in message 2.222... I need to bore a hole in a joist to take a shower waste. Reading the regs tells me that in a 20cm Joist the max hole can be 32mm I need to pass a pipe of 42mm diameter! The joist is right next to a wall at the outer edge of the house - load on it will never be high. Pragmatically - would you go ahead and bore the hole? go on take a chance ...all the other joists and flooringwill stop anything bad happening....... |
#9
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Hole in Joist
On 26/06/2019 18:17, DerbyBorn wrote:
I need to bore a hole in a joist to take a shower waste. Reading the regs tells me that in a 20cm Joist the max hole can be 32mm I need to pass a pipe of 42mm diameter! The joist is right next to a wall at the outer edge of the house - load on it will never be high. Pragmatically - would you go ahead and bore the hole? yes. I might add another joist alongside -- It is hard to imagine a more stupid decision or more dangerous way of making decisions than by putting those decisions in the hands of people who pay no price for being wrong. Thomas Sowell |
#10
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Hole in Joist
On 26/06/2019 18:17, DerbyBorn wrote:
I need to bore a hole in a joist to take a shower waste. Reading the regs tells me that in a 20cm Joist the max hole can be 32mm That is probably a *suggestion* that means in the case of thick plunbers they will never cause the joist to collapse. I need to pass a pipe of 42mm diameter! The joist is right next to a wall at the outer edge of the house - load on it will never be high. Exactly. And yet the regs don't take that into account. Rules are for the guidance of wise men and the obedience of fools -- It is hard to imagine a more stupid decision or more dangerous way of making decisions than by putting those decisions in the hands of people who pay no price for being wrong. Thomas Sowell |
#11
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Hole in Joist
On 26/06/2019 19:05, Chris Hogg wrote:
On Wed, 26 Jun 2019 18:23:37 +0100, Andy Burns wrote: DerbyBorn wrote: the regs tells me that in a 20cm Joist the max hole can be 32mm I need to pass a pipe of 42mm diameter! Reinforce the joist by bolting metal plates to both sides? The any beam of that sort is in tension along its lower edge, compression along its upper edge, as it takes load. A metal plate along the lower edge should be sufficient, e.g. a long mending plate or flat strap, something like this https://tinyurl.com/y3wloogy But IANA structural engineer! TBH slap[ping somne falss fibre n each side woul probably do a huge amouint. I actually did this for a model plane wingh - calculated the increase in strength of a wing with a carbon fibre strip glued along the top and bottom of the main spar. MASSIVE increase in strength with just a tiny amount of carbon fibre. Wood is cheap. Its also a crap structural material. https://www.scottsofthrapston.co.uk/...-floor-joists/ Is where things are going as wood gets more expensive -- If you tell a lie big enough and keep repeating it, people will eventually come to believe it. The lie can be maintained only for such time as the State can shield the people from the political, economic and/or military consequences of the lie. It thus becomes vitally important for the State to use all of its powers to repress dissent, for the truth is the mortal enemy of the lie, and thus by extension, the truth is the greatest enemy of the State. Joseph Goebbels |
#12
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Hole in Joist
On 26/06/2019 19:47, DerbyBorn wrote:
John Rumm wrote in o.uk: On 26/06/2019 18:17, DerbyBorn wrote: I need to bore a hole in a joist to take a shower waste. Reading the regs tells me that in a 20cm Joist the max hole can be 32mm I need to pass a pipe of 42mm diameter! The joist is right next to a wall at the outer edge of the house - load on it will never be high. Pragmatically - would you go ahead and bore the hole? Yes. (noting a hole in the centre is better mid span, and a notch better near the ends) I now reckon I am okay up to 50mm on a 200mm deep joist: https://www.labc.co.uk/news/how-get-...-solid-timber- joists I was going to say what John said. But that link looks pretty good to me! |
#13
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Hole in Joist
I was just going to say something similar, even a second piece of timber
suitable attached across the weakened point might be enough. It very much depends on the place and design of the building I guess. Brian -- ----- -- This newsgroup posting comes to you directly from... The Sofa of Brian Gaff... Blind user, so no pictures please Note this Signature is meaningless.! "Andy Burns" wrote in message ... DerbyBorn wrote: the regs tells me that in a 20cm Joist the max hole can be 32mm I need to pass a pipe of 42mm diameter! Reinforce the joist by bolting metal plates to both sides? |
#14
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Hole in Joist
On Wednesday, 26 June 2019 18:17:47 UTC+1, DerbyBorn wrote:
I need to bore a hole in a joist to take a shower waste. Reading the regs tells me that in a 20cm Joist the max hole can be 32mm I need to pass a pipe of 42mm diameter! The joist is right next to a wall at the outer edge of the house - load on it will never be high. Pragmatically - would you go ahead and bore the hole? The regs on joist sizes have nothing to do with safety. They're more about meeting noise transmission targets. If OTOH it's an old house with bouncy floors I'd add noggings each side of a large hole. But 2" out of 8" isn't large. NT |
#15
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Hole in Joist
On Wednesday, 26 June 2019 18:17:47 UTC+1, DerbyBorn wrote:
I need to bore a hole in a joist to take a shower waste. Reading the regs tells me that in a 20cm Joist the max hole can be 32mm I need to pass a pipe of 42mm diameter! The joist is right next to a wall at the outer edge of the house - load on it will never be high. Pragmatically - would you go ahead and bore the hole? Glue and screw an extra bit of wood on to the joist spanning the hole. PVA would do the jpb Drill the hole through both joist and wood. |
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