Subfloor pipework

[BurstPipe]

Good afternoon all,

I have commenced an extension to my house and as part of this includes the main bathroom.
The proposed floor construction make up is 150mm type 1, DPM, 150mm concrete, 150mm Insulation, and 70mm Screed.

I plan to have all the subfloor pipework popups in-situ prior to pouring the concrete slab.

However, I have a few questions which I would be grateful for some advice:

1. What level should I run the sub floor pipework at? Within the type1 layer for the WC, sink, shower & bath? Surrounding the pipework in pea gravel.

2. Should I install 110mm underground pop ups to all fixtures & common them below ground to a main 110mm line? I had then just planned to install adaptors within the installation layer for the sink, bath & shower popups proposed to use 50mm for each.

The common 110mm would just go through foundations blockwork walls before discharging into a new external inspection chamber.

I plan to install a vent pipe upstream of this manhole to ensure the drain is ventilated.

Thanks in advance,

 

[BurstPipe]

Downloaded sketchup & knocked the below up to try and explain better.

Proposing W/C directly into inspection chamber in 110mm. The sink, shower & bath increasing to 110mm at screed finished level and the communing the three up in 110mm under concrete slab and connecting into the Soil Vent Pipe before discharging into main drain heading towards inspection chamber.

Reading the regulations I am still unsure if I require additional venting of the combined branch or will lengths of pipework & the oversize pipe eliminate the need??

The bathroom is only 2.3mx3.1m.

Thanks in advance,

Cal

 

[oz-plumber]

Is your budget that tight that you can't afford 4 hours for a Plumber to come and do the drains?

As for venting - need to know whether the main drain outside is vented.
There is a distance you can run an unvented branch drain. It depends on length of drain, size of drain and amount of fixtures the drain is picking up.

I would hazard a guess that the whole bathroom doesn't need a vent at all, and all the drains could be combined.

But what would I know - only been Plumbing for 25 years.

 

[BurstPipe]

Is your budget that tight that you can't afford 4 hours for a Plumber to come and do the drains?

As for venting - need to know whether the main drain outside is vented.
There is a distance you can run an unvented branch drain. It depends on length of drain, size of drain and amount of fixtures the drain is picking up.

I would hazard a guess that the whole bathroom doesn't need a vent at all, and all the drains could be combined.

But what would I know - only been Plumbing for 25 years.

Hi Oz,

I had a plumber/GSR engineer round this week servicing my boiler & @ the same time did asked if he did underground slab pipework works. Unfortunate he said it was was typically left for the ground workers to do.

You local?!? I'm south of Glasgow. Happy to employ the services of a plumber to assist in giving me some guidance.

Cheers.

 

[brum]

That can be totally simplified if it was a new build there would be one four inch pipe leaving building only with everything else branched off it but don't forget access boss ...brum

 

[brum]

Having a better look at drawing 4inch pipe from basins etc needs,to terminate in IC to allow testing for building control..brum

 

[BurstPipe]

Cheers Brum. Have dropped you an email.