Bypassing Joist

[Gizzydash]

Hi all,

Looking for some suggestions about how I get 22mm copper pipes around/through a joist (97mm).

Notching on top isn't an option as notch would be too deep. I think I can go through middle via drilling holes but plumber is talking about not having enough space to get joins in and solder. Going under and up - plumber again saying he would need to go back to T, get straight section in, then down and back up other side of joist - then he was concerned about introducing an airlock.

Pipes come into the room from a T set back about 12 inches then there would be the joist where the 2 pipes come in and it Ts off again on the opposite side of where the joist should be.

Any thoughts on best approach would be appreciated.

 

[Mike2007]

If someone hasn't allowed for building services (plumbing + electrics) then they are to blame. Obviously a deeper joist or new direction for pipework would seem more feasible?

 

[Madrab]

What depth will be/is the joist? 22mm will happily sit within a notched standard depth joist. As long as the joist is at least 100mm deep then it shouldn't be an issue unless it's an engineered I joist or a webbed easijoist and then you just go through the middle of it.

 

[footprints]

What about a dwarf wall to support / reinforce the cut joist?

 

[Madrab]

Or just get the plumber to redo the tee's somewhere else, come through that wall and then bend out the way then make the branch

 

[Gizzydash]

Joist is 97mm, so notch would only be 12mm. I had thought about notching that much out of joist and 10mm out of underside of chipboard floor - 10mm channel where pipe would be sitting proud.

Anywhere along the length of the joist i'd still need to go under and back up, worried about airlocks with that. I had thought straight through middle of joist would be easiest but plumber not too keen on that/says it would be big job.

 

[JimCrow]

What depth will be/is the joist? 22mm will happily sit within a notched standard depth joist. As long as the joist is at least 100mm deep then it shouldn't be an issue unless it's an engineered I joist or a webbed easijoist and then you just go through the middle of it.

The minimum depth of joist for a notch for a 22mm pipe is 176mm.

 

[big-all]

What depth will be/is the joist? 22mm will happily sit within a notched standard depth joist. As long as the joist is at least 100mm deep then it shouldn't be an issue unless it's an engineered I joist or a webbed easijoist and then you just go through the middle of it.

its 1/8th for a notch so 97mm divx8=12mm
24mm is a hole centrally

 

[oldbutnotdead]

Bit of a design fail really.
Easiest is prop the joist you'll be notching- depending on clearance to subfloor could be as simple as a standard concrete block with a bit of 4 x 2 sitting on it (on some dpm of course).
Centre drilling is fine but a right pain for the plumber unless you're putting new joists in. And a warning- 4 x 2 joists even on a permitted 1800 span flex quite a lot, enough to give you trouble in 10 years or so.
Down then up is ok usually- air rises so as long as he uses swept bends it'd be fine.

 

[Madrab]

Yup Yup Yup, that'll teach me to pile in when I'm just through the door and not thinking right. 0.125 for the notch, 0.25 for the hole

Jeesh, peeps aren't slow on here today

 

[BlueLoo]

Perhaps.....

Notch the top of the beam for 15mm piping, and split the 22 into two 15's before and after (Top flat reducers).

 

[big-all]

Yup Yup Yup, that'll teach me to pile in when I'm just through the door and not thinking right. 0.125 for the notch, 0.25 for the hole

Jeesh, peeps aren't slow on here today

we have all done it
we know we will be corrected by someone before the ceiling collapses

 

[Gizzydash]

Thanks all - think the only real solution is two 24mm holes in the centre of the joist. Plumber not so keen to do that though, will need bit of convincing!

 

[DavidLewis]

This is a situation where plastic pipe would come into its own. A long length of it could be threaded through as many holes as necessary, to go all the way from where it starts to where it's needed with zero joins.

 

[Dereekoo]

If someone hasn't allowed for building services (plumbing + electrics) then they are to blame. Obviously a deeper joist or new direction for pipework would seem more feasible?

As stated a deeper joist or existing joist set 25mm deeper and then 25mm spacer piece on top with gap for pipes