Bath waste pipe run

[tukky142]

Hi,

I am about to embark on re-fitting my bathroom. I am going to move the bath around. I would like to know what is the best way to run the waste pipe from the bath. The bath will be in the corner of the room diagnollay oppoisite to where the waste stack is. Will it be ok to run the waste so it runs along the wall and then does a 90degree turn, along the other wall and into the waste stack? Should I attempt to run it under the floor boards which will mean choping out the joists??

Thanks in advance

Tuk

 

[chrishutt]

Best to run the waste above floor if you can. It usually depends on the levels possible given the height of the trap outlet. Various bath waste outlets and traps are available to maximise the height of trap outlet. A fall of about 25mm per metre run is considered right, but slightly more or less is acceptable.

 

[ChrisR]

It'll be too much to chop out of the joists. If you can keep an even downhill around 1 in 40 or more, all should be OK. I would try hard to include rodding point(s). How far is the total length, more than about 4m and you'd want to use 50mm instead of 40.

 

[tukky142]

The bath is going to be a shaower bath - I will tray and get the trap as high as possible - The problem I have is that my bathroom has a falt roof so headroom is at a minimum - I must keep bath at lowest setting possible.

The total run will be about 2.5 meters. I think will go straight through the wall at this point and then put a greater fall on the pipe into the stack outside.

Do you think 40mm will be ok from a bath?

 

[chrishutt]

You need to check out Building Regulations Document H1 on two-jags site. Tells you about falls, run lengths and stack connection positions.

 

[tukky142]

Very funny - Two jags!!

 

[chrishutt]

To be honest I think it might have been done before.