Notching joists to run services

[chriselevate]

Just wondered what the advice was for running services such as hot/cold water pipes, waste pipes, heating pipes and cables through joists.

I’m having a new bathroom fitted and I don’t anyone weakening my joists to get it in.

 

[delmel]

Notching joists is not supposed to be done, but people do. The reasons are weakens the joist but also the pipes, cables or what ever are generally left unprotected and easily pierced. There was something called faceplate's that gave minimal protection. Just not good practise.

 

[jj4091]

http://www.diydoctor.org.uk/projects/Notching_joist.htm

 

[chriselevate]

Thanks guys, appreciate it.

 

[foxhole]

I drilled hole for cables at least 80mm from top or bottom of joists to avoid damage from fixings.
With careful planning my pipe work is all fed from above thru walls and waste runs thru wall or inline with joists.

 

[chriselevate]

So you wouldn’t say that a shower tray waste can be run through a joist? Avoid that if possible yeah?

 

[Keithmac]

Our waste runs parrallel to the joists. There'd be nothing left if you cut a 40mm hole through them?.

 

[chriselevate]

Yeah that’s what I thought. It needs to run parallel but the through one joist. Think of asking the joiner to put a trimmer at that point so it’s better than notching out 40mm like you said.

 

[chriselevate]

With 15mm mains water, hw pipes and 15mm ch pipes would you do anything to fix/clip they into the notched joists or anything to lag them?

It’s bit great hearing them expand and contract as ch comes on/off etc.

Thanks.

 

[AlanE]

Wrap felt type pipe insulation around each pipe at each joist cutout.

 

[chriselevate]

Thanks.

No need to lag the whole pipe? That’s optional I guess? I bought a load of felt insulation yesterday so I’m happy to use it if necessary.

 

[AlanE]

Thanks.

No need to lag the whole pipe? That’s optional I guess? I bought a load of felt insulation yesterday so I’m happy to use it if necessary.

Normally downstairs heatin pipes are lagged upstairs not as any heat loss is considered to add to the overal heating of room.

Lagging over the joist is simply to provide a means for pipe expansion without pipe actually rubbing on wooden joist. This use is not to provide insulation but noise free expansion

 

[chriselevate]

Perfect... that makes sense thanks.

What would you suggest for mains water and hot water that is run through first floor joists? The same? Just lag where they are contact with the joists? Or lag more of the pipes?

 

[endecotp]

You should lag everything - unless you are convinced that its heat loss is always useful.
Hot water pipes should always be lagged, no exceptions.
Cold water pipes should be planned so that the water is cool enough to drink; they should definitely be lagged if run next to CH or hot water pipes.
CH pipes should be lagged, except optionally where they only serve one room and they are under to floor of that room.

 

[chriselevate]

That makes sense. When you talk about cold water pipes... you mean they should be kept away from hot pipes or if they are near hot pipes they would be lagged with the felt lagging stuff?

Thanks for your help on this guys.